Adding upstream version 1.21.upstream/1.21 upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
author: Daniel Baumann <daniel.baumann@progress-linux.org> 2024-04-27 17:47:50 +0000
committer: Daniel Baumann <daniel.baumann@progress-linux.org> 2024-04-27 17:47:50 +0000
commit: bbe35a6e1b54ef5cd7c1c471886c30ba85c0804e (patch)
tree: 985a31e8c860c690d9f20e6621ce5fcc05ccd244 /m4
parent: Initial commit. (diff)
download: wget-bbe35a6e1b54ef5cd7c1c471886c30ba85c0804e.tar.xz
wget-bbe35a6e1b54ef5cd7c1c471886c30ba85c0804e.zip
264 files changed, 28691 insertions, 0 deletions
diff --git a/m4/00gnulib.m4 b/m4/00gnulib.m4
new file mode 100644
index 0000000..14628c3
--- /dev/null
+++ b/m4/00gnulib.m4
@@ -0,0 +1,85 @@
+# 00gnulib.m4 serial 8
+dnl Copyright (C) 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl This file must be named something that sorts before all other
+dnl gnulib-provided .m4 files.  It is needed until the clang fix has
+dnl been included in Autoconf.
+
+# The following definitions arrange to use a compiler option
+# -Werror=implicit-function-declaration in AC_CHECK_DECL, when the
+# compiler is clang.  Without it, clang implicitly declares "known"
+# library functions in C mode, but not in C++ mode, which would cause
+# Gnulib to omit a declaration and thus later produce an error in C++
+# mode.  As of clang 9.0, these "known" functions are identified through
+# LIBBUILTIN invocations in the LLVM source file
+# llvm/tools/clang/include/clang/Basic/Builtins.def.
+# It's not possible to AC_REQUIRE the extra tests from AC_CHECK_DECL,
+# because AC_CHECK_DECL, like other Autoconf built-ins, is not supposed
+# to AC_REQUIRE anything: some configure.ac files have their first
+# AC_CHECK_DECL executed conditionally.  Therefore append the extra tests
+# to AC_PROG_CC.
+AC_DEFUN([gl_COMPILER_CLANG],
+[
+dnl AC_REQUIRE([AC_PROG_CC])
+  AC_CACHE_CHECK([whether the compiler is clang],
+    [gl_cv_compiler_clang],
+    [dnl Use _AC_COMPILE_IFELSE instead of AC_EGREP_CPP, to avoid error
+     dnl "circular dependency of AC_LANG_COMPILER(C)" if AC_PROG_CC has
+     dnl not yet been invoked.
+     _AC_COMPILE_IFELSE(
+        [AC_LANG_PROGRAM([[
+           #ifdef __clang__
+           barfbarf
+           #endif
+           ]],[[]])
+        ],
+        [gl_cv_compiler_clang=no],
+        [gl_cv_compiler_clang=yes])
+    ])
+])
+AC_DEFUN([gl_COMPILER_PREPARE_CHECK_DECL],
+[
+dnl AC_REQUIRE([AC_PROG_CC])
+dnl AC_REQUIRE([gl_COMPILER_CLANG])
+  AC_CACHE_CHECK([for compiler option needed when checking for declarations],
+    [gl_cv_compiler_check_decl_option],
+    [if test $gl_cv_compiler_clang = yes; then
+       dnl Test whether the compiler supports the option
+       dnl '-Werror=implicit-function-declaration'.
+       save_ac_compile="$ac_compile"
+       ac_compile="$ac_compile -Werror=implicit-function-declaration"
+       dnl Use _AC_COMPILE_IFELSE instead of AC_COMPILE_IFELSE, to avoid a
+       dnl warning "AC_COMPILE_IFELSE was called before AC_USE_SYSTEM_EXTENSIONS".
+       _AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[]],[[]])],
+         [gl_cv_compiler_check_decl_option='-Werror=implicit-function-declaration'],
+         [gl_cv_compiler_check_decl_option=none])
+       ac_compile="$save_ac_compile"
+     else
+       gl_cv_compiler_check_decl_option=none
+     fi
+    ])
+  if test "x$gl_cv_compiler_check_decl_option" != xnone; then
+    ac_compile_for_check_decl="$ac_compile $gl_cv_compiler_check_decl_option"
+  else
+    ac_compile_for_check_decl="$ac_compile"
+  fi
+])
+dnl Redefine _AC_CHECK_DECL_BODY so that it references ac_compile_for_check_decl
+dnl instead of ac_compile.  If, for whatever reason, the override of AC_PROG_CC
+dnl in zzgnulib.m4 is inactive, use the original ac_compile.
+m4_define([_AC_CHECK_DECL_BODY],
+[  ac_save_ac_compile="$ac_compile"
+  if test -n "$ac_compile_for_check_decl"; then
+    ac_compile="$ac_compile_for_check_decl"
+  fi]
+m4_defn([_AC_CHECK_DECL_BODY])[  ac_compile="$ac_save_ac_compile"
+])
+
+# gl_00GNULIB
+# -----------
+# Witness macro that this file has been included.  Needed to force
+# Automake to include this file prior to all other gnulib .m4 files.
+AC_DEFUN([gl_00GNULIB])
diff --git a/m4/__inline.m4 b/m4/__inline.m4
new file mode 100644
index 0000000..520c8c4
--- /dev/null
+++ b/m4/__inline.m4
@@ -0,0 +1,22 @@
+# Test for __inline keyword
+dnl Copyright 2017-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl___INLINE],
+[
+  AC_CACHE_CHECK([whether the compiler supports the __inline keyword],
+    [gl_cv_c___inline],
+    [AC_COMPILE_IFELSE(
+       [AC_LANG_PROGRAM(
+         [[typedef int foo_t;
+           static __inline foo_t foo (void) { return 0; }]],
+         [[return foo ();]])],
+       [gl_cv_c___inline=yes],
+       [gl_cv_c___inline=no])])
+  if test $gl_cv_c___inline = yes; then
+    AC_DEFINE([HAVE___INLINE], [1],
+      [Define to 1 if the compiler supports the keyword '__inline'.])
+  fi
+])
diff --git a/m4/absolute-header.m4 b/m4/absolute-header.m4
new file mode 100644
index 0000000..c043233
--- /dev/null
+++ b/m4/absolute-header.m4
@@ -0,0 +1,100 @@
+# absolute-header.m4 serial 17
+dnl Copyright (C) 2006-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl From Derek Price.
+
+# gl_ABSOLUTE_HEADER(HEADER1 HEADER2 ...)
+# ---------------------------------------
+# Find the absolute name of a header file, testing first if the header exists.
+# If the header were sys/inttypes.h, this macro would define
+# ABSOLUTE_SYS_INTTYPES_H to the '""' quoted absolute name of sys/inttypes.h
+# in config.h
+# (e.g. '#define ABSOLUTE_SYS_INTTYPES_H "///usr/include/sys/inttypes.h"').
+# The three "///" are to pacify Sun C 5.8, which otherwise would say
+# "warning: #include of /usr/include/... may be non-portable".
+# Use '""', not '<>', so that the /// cannot be confused with a C99 comment.
+# Note: This macro assumes that the header file is not empty after
+# preprocessing, i.e. it does not only define preprocessor macros but also
+# provides some type/enum definitions or function/variable declarations.
+AC_DEFUN([gl_ABSOLUTE_HEADER],
+[AC_REQUIRE([AC_CANONICAL_HOST])
+AC_LANG_PREPROC_REQUIRE()dnl
+m4_foreach_w([gl_HEADER_NAME], [$1],
+  [AS_VAR_PUSHDEF([gl_absolute_header],
+                  [gl_cv_absolute_]m4_defn([gl_HEADER_NAME]))dnl
+  AC_CACHE_CHECK([absolute name of <]m4_defn([gl_HEADER_NAME])[>],
+    [gl_absolute_header],
+    [AS_VAR_PUSHDEF([ac_header_exists],
+                    [ac_cv_header_]m4_defn([gl_HEADER_NAME]))dnl
+    AC_CHECK_HEADERS_ONCE(m4_defn([gl_HEADER_NAME]))dnl
+    if test AS_VAR_GET([ac_header_exists]) = yes; then
+      gl_ABSOLUTE_HEADER_ONE(m4_defn([gl_HEADER_NAME]))
+    fi
+    AS_VAR_POPDEF([ac_header_exists])dnl
+    ])dnl
+  AC_DEFINE_UNQUOTED(AS_TR_CPP([ABSOLUTE_]m4_defn([gl_HEADER_NAME])),
+                     ["AS_VAR_GET([gl_absolute_header])"],
+                     [Define this to an absolute name of <]m4_defn([gl_HEADER_NAME])[>.])
+  AS_VAR_POPDEF([gl_absolute_header])dnl
+])dnl
+])# gl_ABSOLUTE_HEADER
+
+# gl_ABSOLUTE_HEADER_ONE(HEADER)
+# ------------------------------
+# Like gl_ABSOLUTE_HEADER, except that:
+#   - it assumes that the header exists,
+#   - it uses the current CPPFLAGS,
+#   - it does not cache the result,
+#   - it is silent.
+AC_DEFUN([gl_ABSOLUTE_HEADER_ONE],
+[
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  AC_LANG_CONFTEST([AC_LANG_SOURCE([[#include <]]m4_dquote([$1])[[>]])])
+  dnl AIX "xlc -E" and "cc -E" omit #line directives for header files
+  dnl that contain only a #include of other header files and no
+  dnl non-comment tokens of their own. This leads to a failure to
+  dnl detect the absolute name of <dirent.h>, <signal.h>, <poll.h>
+  dnl and others. The workaround is to force preservation of comments
+  dnl through option -C. This ensures all necessary #line directives
+  dnl are present. GCC supports option -C as well.
+  case "$host_os" in
+    aix*) gl_absname_cpp="$ac_cpp -C" ;;
+    *)    gl_absname_cpp="$ac_cpp" ;;
+  esac
+changequote(,)
+  case "$host_os" in
+    mingw*)
+      dnl For the sake of native Windows compilers (excluding gcc),
+      dnl treat backslash as a directory separator, like /.
+      dnl Actually, these compilers use a double-backslash as
+      dnl directory separator, inside the
+      dnl   # line "filename"
+      dnl directives.
+      gl_dirsep_regex='[/\\]'
+      ;;
+    *)
+      gl_dirsep_regex='\/'
+      ;;
+  esac
+  dnl A sed expression that turns a string into a basic regular
+  dnl expression, for use within "/.../".
+  gl_make_literal_regex_sed='s,[]$^\\.*/[],\\&,g'
+  gl_header_literal_regex=`echo '$1' \
+                           | sed -e "$gl_make_literal_regex_sed"`
+  gl_absolute_header_sed="/${gl_dirsep_regex}${gl_header_literal_regex}/"'{
+      s/.*"\(.*'"${gl_dirsep_regex}${gl_header_literal_regex}"'\)".*/\1/
+      s|^/[^/]|//&|
+      p
+      q
+    }'
+changequote([,])
+  dnl eval is necessary to expand gl_absname_cpp.
+  dnl Ultrix and Pyramid sh refuse to redirect output of eval,
+  dnl so use subshell.
+  AS_VAR_SET([gl_cv_absolute_]AS_TR_SH([[$1]]),
+[`(eval "$gl_absname_cpp conftest.$ac_ext") 2>&AS_MESSAGE_LOG_FD |
+  sed -n "$gl_absolute_header_sed"`])
+])
diff --git a/m4/access.m4 b/m4/access.m4
new file mode 100644
index 0000000..cfe799d
--- /dev/null
+++ b/m4/access.m4
@@ -0,0 +1,16 @@
+# access.m4 serial 1
+dnl Copyright (C) 2019-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_ACCESS],
+[
+  AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  dnl On native Windows, access (= _access) does not support the X_OK mode.
+  dnl It works by chance on some versions of mingw.
+  case "$host_os" in
+    mingw*) REPLACE_ACCESS=1 ;;
+  esac
+])
diff --git a/m4/af_alg.m4 b/m4/af_alg.m4
new file mode 100644
index 0000000..418d690
--- /dev/null
+++ b/m4/af_alg.m4
@@ -0,0 +1,56 @@
+# af_alg.m4 serial 4
+dnl Copyright 2018-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl From Matteo Croce.
+
+AC_DEFUN_ONCE([gl_AF_ALG],
+[
+  AC_REQUIRE([gl_HEADER_SYS_SOCKET])
+  AC_REQUIRE([AC_C_INLINE])
+
+  dnl Check whether linux/if_alg.h has needed features.
+  AC_CACHE_CHECK([whether linux/if_alg.h has struct sockaddr_alg.],
+    [gl_cv_header_linux_if_alg_salg],
+    [AC_COMPILE_IFELSE(
+       [AC_LANG_PROGRAM([[#include <sys/socket.h>
+                          #include <linux/if_alg.h>
+                          struct sockaddr_alg salg = {
+                            .salg_family = AF_ALG,
+                            .salg_type = "hash",
+                            .salg_name = "sha1",
+                          };]])],
+       [gl_cv_header_linux_if_alg_salg=yes],
+       [gl_cv_header_linux_if_alg_salg=no])])
+  if test "$gl_cv_header_linux_if_alg_salg" = yes; then
+    AC_DEFINE([HAVE_LINUX_IF_ALG_H], [1],
+      [Define to 1 if you have 'struct sockaddr_alg' defined.])
+  fi
+
+  dnl The default is to not use AF_ALG if available,
+  dnl as it's system dependent as to whether the kernel
+  dnl routines are faster than libcrypto for example.
+  use_af_alg=no
+  AC_ARG_WITH([linux-crypto],
+    [AS_HELP_STRING([[--with-linux-crypto]],
+       [use Linux kernel cryptographic API (if available)])],
+    [use_af_alg=$withval],
+    [use_af_alg=no])
+  dnl We cannot use it if it is not available.
+  if test "$gl_cv_header_linux_if_alg_salg" != yes; then
+    if test "$use_af_alg" != no; then
+      AC_MSG_WARN([Linux kernel cryptographic API not found])
+    fi
+    use_af_alg=no
+  fi
+
+  if test "$use_af_alg" != no; then
+    USE_AF_ALG=1
+  else
+    USE_AF_ALG=0
+  fi
+  AC_DEFINE_UNQUOTED([USE_LINUX_CRYPTO_API], [$USE_AF_ALG],
+    [Define to 1 if you want to use the Linux kernel cryptographic API.])
+])
diff --git a/m4/alloca.m4 b/m4/alloca.m4
new file mode 100644
index 0000000..e3c377c
--- /dev/null
+++ b/m4/alloca.m4
@@ -0,0 +1,108 @@
+# alloca.m4 serial 20
+dnl Copyright (C) 2002-2004, 2006-2007, 2009-2020 Free Software Foundation,
+dnl Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_ALLOCA],
+[
+  AC_REQUIRE([AC_FUNC_ALLOCA])
+  if test $ac_cv_func_alloca_works = no; then
+    gl_PREREQ_ALLOCA
+  fi
+
+  # Define an additional variable used in the Makefile substitution.
+  if test $ac_cv_working_alloca_h = yes; then
+    AC_CACHE_CHECK([for alloca as a compiler built-in], [gl_cv_rpl_alloca], [
+      AC_EGREP_CPP([Need own alloca], [
+#if defined __GNUC__ || defined _AIX || defined _MSC_VER
+        Need own alloca
+#endif
+        ], [gl_cv_rpl_alloca=yes], [gl_cv_rpl_alloca=no])
+    ])
+    if test $gl_cv_rpl_alloca = yes; then
+      dnl OK, alloca can be implemented through a compiler built-in.
+      AC_DEFINE([HAVE_ALLOCA], [1],
+        [Define to 1 if you have 'alloca' after including <alloca.h>,
+         a header that may be supplied by this distribution.])
+      ALLOCA_H=alloca.h
+    else
+      dnl alloca exists as a library function, i.e. it is slow and probably
+      dnl a memory leak. Don't define HAVE_ALLOCA in this case.
+      ALLOCA_H=
+    fi
+  else
+    ALLOCA_H=alloca.h
+  fi
+  AC_SUBST([ALLOCA_H])
+  AM_CONDITIONAL([GL_GENERATE_ALLOCA_H], [test -n "$ALLOCA_H"])
+
+  if test $ac_cv_working_alloca_h = yes; then
+    HAVE_ALLOCA_H=1
+  else
+    HAVE_ALLOCA_H=0
+  fi
+  AC_SUBST([HAVE_ALLOCA_H])
+])
+
+# Prerequisites of lib/alloca.c.
+# STACK_DIRECTION is already handled by AC_FUNC_ALLOCA.
+AC_DEFUN([gl_PREREQ_ALLOCA], [:])
+
+m4_version_prereq([2.70], [], [
+
+# This works around a bug in autoconf <= 2.68 and has simplifications
+# from 2.70.  See:
+# https://lists.gnu.org/r/bug-gnulib/2011-06/msg00277.html
+# https://git.savannah.gnu.org/cgit/autoconf.git/commit/?id=6cd9f12520b0d6f76d3230d7565feba1ecf29497
+# https://git.savannah.gnu.org/cgit/autoconf.git/commit/?id=15edf7fd8094fd14a89d9891dd72a9624762597a
+
+# _AC_LIBOBJ_ALLOCA
+# -----------------
+# Set up the LIBOBJ replacement of 'alloca'.  Well, not exactly
+# AC_LIBOBJ since we actually set the output variable 'ALLOCA'.
+# Nevertheless, for Automake, AC_LIBSOURCES it.
+m4_define([_AC_LIBOBJ_ALLOCA],
+[# The SVR3 libPW and SVR4 libucb both contain incompatible functions
+# that cause trouble.  Some versions do not even contain alloca or
+# contain a buggy version.  If you still want to use their alloca,
+# use ar to extract alloca.o from them instead of compiling alloca.c.
+AC_LIBSOURCES(alloca.c)
+AC_SUBST([ALLOCA], [\${LIBOBJDIR}alloca.$ac_objext])dnl
+AC_DEFINE(C_ALLOCA, 1, [Define to 1 if using 'alloca.c'.])
+
+AC_CACHE_CHECK([stack direction for C alloca],
+               [ac_cv_c_stack_direction],
+[AC_RUN_IFELSE([AC_LANG_SOURCE(
+[AC_INCLUDES_DEFAULT
+int
+find_stack_direction (int *addr, int depth)
+{
+  int dir, dummy = 0;
+  if (! addr)
+    addr = &dummy;
+  *addr = addr < &dummy ? 1 : addr == &dummy ? 0 : -1;
+  dir = depth ? find_stack_direction (addr, depth - 1) : 0;
+  return dir + dummy;
+}
+
+int
+main (int argc, char **argv)
+{
+  return find_stack_direction (0, argc + !argv + 20) < 0;
+}])],
+               [ac_cv_c_stack_direction=1],
+               [ac_cv_c_stack_direction=-1],
+               [ac_cv_c_stack_direction=0])])
+AH_VERBATIM([STACK_DIRECTION],
+[/* If using the C implementation of alloca, define if you know the
+   direction of stack growth for your system; otherwise it will be
+   automatically deduced at runtime.
+        STACK_DIRECTION > 0 => grows toward higher addresses
+        STACK_DIRECTION < 0 => grows toward lower addresses
+        STACK_DIRECTION = 0 => direction of growth unknown */
+#undef STACK_DIRECTION])dnl
+AC_DEFINE_UNQUOTED(STACK_DIRECTION, $ac_cv_c_stack_direction)
+])# _AC_LIBOBJ_ALLOCA
+])
diff --git a/m4/arpa_inet_h.m4 b/m4/arpa_inet_h.m4
new file mode 100644
index 0000000..b394494
--- /dev/null
+++ b/m4/arpa_inet_h.m4
@@ -0,0 +1,59 @@
+# arpa_inet_h.m4 serial 14
+dnl Copyright (C) 2006, 2008-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl Written by Simon Josefsson and Bruno Haible
+
+AC_DEFUN([gl_HEADER_ARPA_INET],
+[
+  dnl Use AC_REQUIRE here, so that the default behavior below is expanded
+  dnl once only, before all statements that occur in other macros.
+  AC_REQUIRE([gl_ARPA_INET_H_DEFAULTS])
+
+  AC_CHECK_HEADERS_ONCE([arpa/inet.h])
+  if test $ac_cv_header_arpa_inet_h = yes; then
+    HAVE_ARPA_INET_H=1
+  else
+    HAVE_ARPA_INET_H=0
+  fi
+  AC_SUBST([HAVE_ARPA_INET_H])
+  dnl <arpa/inet.h> is always overridden, because of GNULIB_POSIXCHECK.
+  gl_CHECK_NEXT_HEADERS([arpa/inet.h])
+
+  AC_REQUIRE([gl_FEATURES_H])
+
+  gl_PREREQ_SYS_H_WS2TCPIP
+
+  dnl Check for declarations of anything we want to poison if the
+  dnl corresponding gnulib module is not in use.
+  gl_WARN_ON_USE_PREPARE([[
+/* On some systems, this header is not self-consistent.  */
+#if !(defined __GLIBC__ || defined __UCLIBC__)
+# include <sys/socket.h>
+#endif
+#ifdef __TANDEM
+# include <netdb.h>
+#endif
+#include <arpa/inet.h>
+    ]], [inet_ntop inet_pton])
+])
+
+AC_DEFUN([gl_ARPA_INET_MODULE_INDICATOR],
+[
+  dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
+  AC_REQUIRE([gl_ARPA_INET_H_DEFAULTS])
+  gl_MODULE_INDICATOR_SET_VARIABLE([$1])
+])
+
+AC_DEFUN([gl_ARPA_INET_H_DEFAULTS],
+[
+  GNULIB_INET_NTOP=0;     AC_SUBST([GNULIB_INET_NTOP])
+  GNULIB_INET_PTON=0;     AC_SUBST([GNULIB_INET_PTON])
+  dnl Assume proper GNU behavior unless another module says otherwise.
+  HAVE_DECL_INET_NTOP=1;  AC_SUBST([HAVE_DECL_INET_NTOP])
+  HAVE_DECL_INET_PTON=1;  AC_SUBST([HAVE_DECL_INET_PTON])
+  REPLACE_INET_NTOP=0;    AC_SUBST([REPLACE_INET_NTOP])
+  REPLACE_INET_PTON=0;    AC_SUBST([REPLACE_INET_PTON])
+])
diff --git a/m4/asm-underscore.m4 b/m4/asm-underscore.m4
new file mode 100644
index 0000000..6446e71
--- /dev/null
+++ b/m4/asm-underscore.m4
@@ -0,0 +1,83 @@
+# asm-underscore.m4 serial 5
+dnl Copyright (C) 2010-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl From Bruno Haible. Based on as-underscore.m4 in GNU clisp.
+
+# gl_ASM_SYMBOL_PREFIX
+# Tests for the prefix of C symbols at the assembly language level and the
+# linker level. This prefix is either an underscore or empty. Defines the
+# C macro USER_LABEL_PREFIX to this prefix, and sets ASM_SYMBOL_PREFIX to
+# a stringified variant of this prefix.
+
+AC_DEFUN([gl_ASM_SYMBOL_PREFIX],
+[
+  AC_REQUIRE([AC_PROG_EGREP])
+  dnl We don't use GCC's __USER_LABEL_PREFIX__ here, because
+  dnl 1. It works only for GCC.
+  dnl 2. It is incorrectly defined on some platforms, in some GCC versions.
+  AC_REQUIRE([gl_C_ASM])
+  AC_CACHE_CHECK(
+    [whether C symbols are prefixed with underscore at the linker level],
+    [gl_cv_prog_as_underscore],
+    [cat > conftest.c <<EOF
+#ifdef __cplusplus
+extern "C" int foo (void);
+#endif
+int foo(void) { return 0; }
+EOF
+     # Look for the assembly language name in the .s file.
+     AC_TRY_COMMAND(${CC-cc} $CFLAGS $CPPFLAGS $gl_c_asm_opt conftest.c) >/dev/null 2>&1
+     if LC_ALL=C $EGREP '(^|[[^a-zA-Z0-9_]])_foo([[^a-zA-Z0-9_]]|$)' conftest.$gl_asmext >/dev/null; then
+       gl_cv_prog_as_underscore=yes
+     else
+       gl_cv_prog_as_underscore=no
+     fi
+     rm -f conftest*
+    ])
+  if test $gl_cv_prog_as_underscore = yes; then
+    USER_LABEL_PREFIX=_
+  else
+    USER_LABEL_PREFIX=
+  fi
+  AC_DEFINE_UNQUOTED([USER_LABEL_PREFIX], [$USER_LABEL_PREFIX],
+    [Define to the prefix of C symbols at the assembler and linker level,
+     either an underscore or empty.])
+  ASM_SYMBOL_PREFIX='"'${USER_LABEL_PREFIX}'"'
+  AC_SUBST([ASM_SYMBOL_PREFIX])
+])
+
+# gl_C_ASM
+# Determines how to produce an assembly language file from C source code.
+# Sets the variables:
+#   gl_asmext - the extension of assembly language output,
+#   gl_c_asm_opt - the C compiler option that produces assembly language output.
+
+AC_DEFUN([gl_C_ASM],
+[
+  AC_EGREP_CPP([MicrosoftCompiler],
+    [
+#ifdef _MSC_VER
+MicrosoftCompiler
+#endif
+    ],
+    [dnl Microsoft's 'cl' and 'clang-cl' produce an .asm file, whereas 'clang'
+     dnl produces a .s file. Need to distinguish 'clang' and 'clang-cl'.
+     rm -f conftest*
+     echo 'int dummy;' > conftest.c
+     AC_TRY_COMMAND(${CC-cc} $CFLAGS $CPPFLAGS -c conftest.c) >/dev/null 2>&1
+     if test -f conftest.o; then
+       gl_asmext='s'
+       gl_c_asm_opt='-S'
+     else
+       gl_asmext='asm'
+       gl_c_asm_opt='-c -Fa'
+     fi
+     rm -f conftest*
+    ],
+    [gl_asmext='s'
+     gl_c_asm_opt='-S'
+    ])
+])
diff --git a/m4/base32.m4 b/m4/base32.m4
new file mode 100644
index 0000000..2d07d44
--- /dev/null
+++ b/m4/base32.m4
@@ -0,0 +1,15 @@
+# base32.m4 serial 4
+dnl Copyright (C) 2004, 2006, 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_BASE32],
+[
+  gl_PREREQ_BASE32
+])
+
+# Prerequisites of lib/base32.c.
+AC_DEFUN([gl_PREREQ_BASE32], [
+  AC_REQUIRE([AC_C_RESTRICT])
+])
diff --git a/m4/btowc.m4 b/m4/btowc.m4
new file mode 100644
index 0000000..ec19ea0
--- /dev/null
+++ b/m4/btowc.m4
@@ -0,0 +1,105 @@
+# btowc.m4 serial 12
+dnl Copyright (C) 2008-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_BTOWC],
+[
+  AC_REQUIRE([gl_WCHAR_H_DEFAULTS])
+
+  dnl Check whether <wchar.h> is usable at all, first. Otherwise the test
+  dnl program below may lead to an endless loop. See
+  dnl <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=42440>.
+  AC_REQUIRE([gl_WCHAR_H_INLINE_OK])
+
+  AC_CHECK_FUNCS_ONCE([btowc])
+  if test $ac_cv_func_btowc = no; then
+    HAVE_BTOWC=0
+  else
+
+    AC_REQUIRE([AC_PROG_CC])
+    AC_REQUIRE([gt_LOCALE_FR])
+    AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+
+    dnl Cygwin 1.7.2 btowc('\0') is WEOF, not 0.
+    AC_CACHE_CHECK([whether btowc(0) is correct],
+      [gl_cv_func_btowc_nul],
+      [
+        AC_RUN_IFELSE(
+          [AC_LANG_SOURCE([[
+#include <wchar.h>
+int main ()
+{
+  if (btowc ('\0') != 0)
+    return 1;
+  return 0;
+}]])],
+          [gl_cv_func_btowc_nul=yes],
+          [gl_cv_func_btowc_nul=no],
+          [
+changequote(,)dnl
+           case "$host_os" in
+                      # Guess no on Cygwin.
+             cygwin*) gl_cv_func_btowc_nul="guessing no" ;;
+                      # Guess yes on native Windows.
+             mingw*)  gl_cv_func_btowc_nul="guessing yes" ;;
+                      # Guess yes otherwise.
+             *)       gl_cv_func_btowc_nul="guessing yes" ;;
+           esac
+changequote([,])dnl
+          ])
+      ])
+
+    dnl IRIX 6.5 btowc(EOF) is 0xFF, not WEOF.
+    AC_CACHE_CHECK([whether btowc(EOF) is correct],
+      [gl_cv_func_btowc_eof],
+      [
+        dnl Initial guess, used when cross-compiling or when no suitable locale
+        dnl is present.
+changequote(,)dnl
+        case "$host_os" in
+                  # Guess no on IRIX.
+          irix*)  gl_cv_func_btowc_eof="guessing no" ;;
+                  # Guess yes on native Windows.
+          mingw*) gl_cv_func_btowc_eof="guessing yes" ;;
+                  # Guess yes otherwise.
+          *)      gl_cv_func_btowc_eof="guessing yes" ;;
+        esac
+changequote([,])dnl
+        if test $LOCALE_FR != none; then
+          AC_RUN_IFELSE(
+            [AC_LANG_SOURCE([[
+#include <locale.h>
+#include <stdio.h>
+#include <wchar.h>
+int main ()
+{
+  if (setlocale (LC_ALL, "$LOCALE_FR") != NULL)
+    {
+      if (btowc (EOF) != WEOF)
+        return 1;
+    }
+  return 0;
+}]])],
+            [gl_cv_func_btowc_eof=yes],
+            [gl_cv_func_btowc_eof=no],
+            [:])
+        fi
+      ])
+
+    case "$gl_cv_func_btowc_nul" in
+      *yes) ;;
+      *) REPLACE_BTOWC=1 ;;
+    esac
+    case "$gl_cv_func_btowc_eof" in
+      *yes) ;;
+      *) REPLACE_BTOWC=1 ;;
+    esac
+  fi
+])
+
+# Prerequisites of lib/btowc.c.
+AC_DEFUN([gl_PREREQ_BTOWC], [
+  :
+])
diff --git a/m4/builtin-expect.m4 b/m4/builtin-expect.m4
new file mode 100644
index 0000000..a6e8895
--- /dev/null
+++ b/m4/builtin-expect.m4
@@ -0,0 +1,49 @@
+dnl Check for __builtin_expect.
+
+dnl Copyright 2016-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl Written by Paul Eggert.
+
+AC_DEFUN([gl___BUILTIN_EXPECT],
+[
+  AC_CACHE_CHECK([for __builtin_expect],
+    [gl_cv___builtin_expect],
+    [AC_LINK_IFELSE(
+       [AC_LANG_SOURCE([[
+         int
+         main (int argc, char **argv)
+         {
+           argc = __builtin_expect (argc, 100);
+           return argv[argc != 100][0];
+         }]])],
+       [gl_cv___builtin_expect=yes],
+       [AC_LINK_IFELSE(
+          [AC_LANG_SOURCE([[
+             #include <builtins.h>
+             int
+             main (int argc, char **argv)
+             {
+               argc = __builtin_expect (argc, 100);
+               return argv[argc != 100][0];
+             }]])],
+          [gl_cv___builtin_expect="in <builtins.h>"],
+          [gl_cv___builtin_expect=no])])])
+  if test "$gl_cv___builtin_expect" = yes; then
+    AC_DEFINE([HAVE___BUILTIN_EXPECT], [1])
+  elif test "$gl_cv___builtin_expect" = "in <builtins.h>"; then
+    AC_DEFINE([HAVE___BUILTIN_EXPECT], [2])
+  fi
+  AH_VERBATIM([HAVE___BUILTIN_EXPECT],
+    [/* Define to 1 if the compiler supports __builtin_expect,
+   and to 2 if <builtins.h> does.  */
+#undef HAVE___BUILTIN_EXPECT
+#ifndef HAVE___BUILTIN_EXPECT
+# define __builtin_expect(e, c) (e)
+#elif HAVE___BUILTIN_EXPECT == 2
+# include <builtins.h>
+#endif
+    ])
+])
diff --git a/m4/byteswap.m4 b/m4/byteswap.m4
new file mode 100644
index 0000000..0f43994
--- /dev/null
+++ b/m4/byteswap.m4
@@ -0,0 +1,19 @@
+# byteswap.m4 serial 4
+dnl Copyright (C) 2005, 2007, 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl Written by Oskar Liljeblad.
+
+AC_DEFUN([gl_BYTESWAP],
+[
+  dnl Prerequisites of lib/byteswap.in.h.
+  AC_CHECK_HEADERS([byteswap.h], [
+    BYTESWAP_H=''
+  ], [
+    BYTESWAP_H='byteswap.h'
+  ])
+  AC_SUBST([BYTESWAP_H])
+  AM_CONDITIONAL([GL_GENERATE_BYTESWAP_H], [test -n "$BYTESWAP_H"])
+])
diff --git a/m4/canonicalize.m4 b/m4/canonicalize.m4
new file mode 100644
index 0000000..404db4c
--- /dev/null
+++ b/m4/canonicalize.m4
@@ -0,0 +1,145 @@
+# canonicalize.m4 serial 35
+
+dnl Copyright (C) 2003-2007, 2009-2020 Free Software Foundation, Inc.
+
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+# Provides canonicalize_file_name and canonicalize_filename_mode, but does
+# not provide or fix realpath.
+AC_DEFUN([gl_FUNC_CANONICALIZE_FILENAME_MODE],
+[
+  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+  AC_REQUIRE([gl_FUNC_LSTAT_FOLLOWS_SLASHED_SYMLINK])
+  AC_CHECK_FUNCS_ONCE([canonicalize_file_name faccessat])
+  AC_REQUIRE([gl_DOUBLE_SLASH_ROOT])
+  AC_REQUIRE([gl_FUNC_REALPATH_WORKS])
+  if test $ac_cv_func_canonicalize_file_name = no; then
+    HAVE_CANONICALIZE_FILE_NAME=0
+  else
+    case "$gl_cv_func_realpath_works" in
+      *yes) ;;
+      *)    REPLACE_CANONICALIZE_FILE_NAME=1 ;;
+    esac
+  fi
+])
+
+# Provides canonicalize_file_name and realpath.
+AC_DEFUN([gl_CANONICALIZE_LGPL],
+[
+  AC_REQUIRE([gl_STDLIB_H_DEFAULTS])
+  AC_REQUIRE([gl_CANONICALIZE_LGPL_SEPARATE])
+  if test $ac_cv_func_canonicalize_file_name = no; then
+    HAVE_CANONICALIZE_FILE_NAME=0
+    if test $ac_cv_func_realpath = no; then
+      HAVE_REALPATH=0
+    else
+      case "$gl_cv_func_realpath_works" in
+        *yes) ;;
+        *)    REPLACE_REALPATH=1 ;;
+      esac
+    fi
+  else
+    case "$gl_cv_func_realpath_works" in
+      *yes)
+        ;;
+      *)
+        REPLACE_CANONICALIZE_FILE_NAME=1
+        REPLACE_REALPATH=1
+        ;;
+    esac
+  fi
+])
+
+# Like gl_CANONICALIZE_LGPL, except prepare for separate compilation
+# (no REPLACE_CANONICALIZE_FILE_NAME, no REPLACE_REALPATH, no AC_LIBOBJ).
+AC_DEFUN([gl_CANONICALIZE_LGPL_SEPARATE],
+[
+  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+  AC_REQUIRE([gl_FUNC_LSTAT_FOLLOWS_SLASHED_SYMLINK])
+  AC_CHECK_FUNCS_ONCE([canonicalize_file_name faccessat])
+
+  dnl On native Windows, we use _getcwd(), regardless whether getcwd() is
+  dnl available through the linker option '-loldnames'.
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  case "$host_os" in
+    mingw*) ;;
+    *)      AC_CHECK_FUNCS([getcwd]) ;;
+  esac
+
+  AC_REQUIRE([gl_DOUBLE_SLASH_ROOT])
+  AC_REQUIRE([gl_FUNC_REALPATH_WORKS])
+  AC_CHECK_HEADERS_ONCE([sys/param.h])
+])
+
+# Check whether realpath works.  Assume that if a platform has both
+# realpath and canonicalize_file_name, but the former is broken, then
+# so is the latter.
+AC_DEFUN([gl_FUNC_REALPATH_WORKS],
+[
+  AC_CHECK_FUNCS_ONCE([realpath])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_CACHE_CHECK([whether realpath works], [gl_cv_func_realpath_works], [
+    rm -rf conftest.a conftest.d
+    touch conftest.a
+    mkdir conftest.d
+    AC_RUN_IFELSE([
+      AC_LANG_PROGRAM([[
+        ]GL_NOCRASH[
+        #include <stdlib.h>
+        #include <string.h>
+      ]], [[
+        int result = 0;
+        {
+          char *name = realpath ("conftest.a", NULL);
+          if (!(name && *name == '/'))
+            result |= 1;
+          free (name);
+        }
+        {
+          char *name = realpath ("conftest.b/../conftest.a", NULL);
+          if (name != NULL)
+            result |= 2;
+          free (name);
+        }
+        {
+          char *name = realpath ("conftest.a/", NULL);
+          if (name != NULL)
+            result |= 4;
+          free (name);
+        }
+        {
+          char *name1 = realpath (".", NULL);
+          char *name2 = realpath ("conftest.d//./..", NULL);
+          if (! name1 || ! name2 || strcmp (name1, name2))
+            result |= 8;
+          free (name1);
+          free (name2);
+        }
+        return result;
+      ]])
+     ],
+     [gl_cv_func_realpath_works=yes],
+     [gl_cv_func_realpath_works=no],
+     [case "$host_os" in
+                       # Guess yes on glibc systems.
+        *-gnu* | gnu*) gl_cv_func_realpath_works="guessing yes" ;;
+                       # Guess yes on musl systems.
+        *-musl*)       gl_cv_func_realpath_works="guessing yes" ;;
+                       # Guess no on native Windows.
+        mingw*)        gl_cv_func_realpath_works="guessing no" ;;
+                       # If we don't know, obey --enable-cross-guesses.
+        *)             gl_cv_func_realpath_works="$gl_cross_guess_normal" ;;
+      esac
+     ])
+    rm -rf conftest.a conftest.d
+  ])
+  case "$gl_cv_func_realpath_works" in
+    *yes)
+      AC_DEFINE([FUNC_REALPATH_WORKS], [1], [Define to 1 if realpath()
+        can malloc memory, always gives an absolute path, and handles
+        trailing slash correctly.])
+      ;;
+  esac
+])
diff --git a/m4/chdir-long.m4 b/m4/chdir-long.m4
new file mode 100644
index 0000000..a6e67b5
--- /dev/null
+++ b/m4/chdir-long.m4
@@ -0,0 +1,30 @@
+#serial 17
+
+# Use Gnulib's robust chdir function.
+# It can handle arbitrarily long directory names, which means
+# that when it is given the name of an existing directory, it
+# never fails with ENAMETOOLONG.
+# Arrange to compile chdir-long.c only on systems that define PATH_MAX.
+
+dnl Copyright (C) 2004-2007, 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+# Written by Jim Meyering.
+
+AC_DEFUN([gl_FUNC_CHDIR_LONG],
+[
+  AC_REQUIRE([gl_PATHMAX_SNIPPET_PREREQ])
+  AC_CACHE_CHECK([whether this system supports file names of any length],
+    [gl_cv_have_unlimited_file_name_length],
+    [AC_EGREP_CPP([have_arbitrary_file_name_length_limit],
+                  gl_PATHMAX_SNIPPET[
+#ifdef PATH_MAX
+have_arbitrary_file_name_length_limit
+#endif],
+    [gl_cv_have_unlimited_file_name_length=no],
+    [gl_cv_have_unlimited_file_name_length=yes])])
+])
+
+AC_DEFUN([gl_PREREQ_CHDIR_LONG], [:])
diff --git a/m4/clock_time.m4 b/m4/clock_time.m4
new file mode 100644
index 0000000..f4f51fa
--- /dev/null
+++ b/m4/clock_time.m4
@@ -0,0 +1,31 @@
+# clock_time.m4 serial 10
+dnl Copyright (C) 2002-2006, 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+# Check for clock_gettime and clock_settime, and set LIB_CLOCK_GETTIME.
+# For a program named, say foo, you should add a line like the following
+# in the corresponding Makefile.am file:
+# foo_LDADD = $(LDADD) $(LIB_CLOCK_GETTIME)
+
+AC_DEFUN([gl_CLOCK_TIME],
+[
+  dnl Persuade glibc and Solaris <time.h> to declare these functions.
+  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+
+  # Solaris 2.5.1 needs -lposix4 to get the clock_gettime function.
+  # Solaris 7 prefers the library name -lrt to the obsolescent name -lposix4.
+
+  # Save and restore LIBS so e.g., -lrt, isn't added to it.  Otherwise, *all*
+  # programs in the package would end up linked with that potentially-shared
+  # library, inducing unnecessary run-time overhead.
+  LIB_CLOCK_GETTIME=
+  AC_SUBST([LIB_CLOCK_GETTIME])
+  gl_saved_libs=$LIBS
+    AC_SEARCH_LIBS([clock_gettime], [rt posix4],
+                   [test "$ac_cv_search_clock_gettime" = "none required" ||
+                    LIB_CLOCK_GETTIME=$ac_cv_search_clock_gettime])
+    AC_CHECK_FUNCS([clock_gettime clock_settime])
+  LIBS=$gl_saved_libs
+])
diff --git a/m4/close.m4 b/m4/close.m4
new file mode 100644
index 0000000..378ec4c
--- /dev/null
+++ b/m4/close.m4
@@ -0,0 +1,35 @@
+# close.m4 serial 9
+dnl Copyright (C) 2008-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_CLOSE],
+[
+  AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
+  m4_ifdef([gl_MSVC_INVAL], [
+    AC_REQUIRE([gl_MSVC_INVAL])
+    if test $HAVE_MSVC_INVALID_PARAMETER_HANDLER = 1; then
+      REPLACE_CLOSE=1
+    fi
+  ])
+  m4_ifdef([gl_PREREQ_SYS_H_WINSOCK2], [
+    gl_PREREQ_SYS_H_WINSOCK2
+    if test $UNISTD_H_HAVE_WINSOCK2_H = 1; then
+      dnl Even if the 'socket' module is not used here, another part of the
+      dnl application may use it and pass file descriptors that refer to
+      dnl sockets to the close() function. So enable the support for sockets.
+      REPLACE_CLOSE=1
+    fi
+  ])
+  dnl Replace close() for supporting the gnulib-defined fchdir() function,
+  dnl to keep fchdir's bookkeeping up-to-date.
+  m4_ifdef([gl_FUNC_FCHDIR], [
+    if test $REPLACE_CLOSE = 0; then
+      gl_TEST_FCHDIR
+      if test $HAVE_FCHDIR = 0; then
+        REPLACE_CLOSE=1
+      fi
+    fi
+  ])
+])
diff --git a/m4/closedir.m4 b/m4/closedir.m4
new file mode 100644
index 0000000..66f6d4e
--- /dev/null
+++ b/m4/closedir.m4
@@ -0,0 +1,31 @@
+# closedir.m4 serial 6
+dnl Copyright (C) 2011-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_CLOSEDIR],
+[
+  AC_REQUIRE([gl_DIRENT_H_DEFAULTS])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+
+  AC_CHECK_FUNCS([closedir])
+  if test $ac_cv_func_closedir = no; then
+    HAVE_CLOSEDIR=0
+  fi
+  dnl Replace closedir() for supporting the gnulib-defined fchdir() function,
+  dnl to keep fchdir's bookkeeping up-to-date.
+  m4_ifdef([gl_FUNC_FCHDIR], [
+    gl_TEST_FCHDIR
+    if test $HAVE_FCHDIR = 0; then
+      if test $HAVE_CLOSEDIR = 1; then
+        REPLACE_CLOSEDIR=1
+      fi
+    fi
+  ])
+  dnl Replace closedir() for supporting the gnulib-defined dirfd() function.
+  case $host_os,$HAVE_CLOSEDIR in
+    os2*,1)
+      REPLACE_CLOSEDIR=1;;
+  esac
+])
diff --git a/m4/codeset.m4 b/m4/codeset.m4
new file mode 100644
index 0000000..9b019cf
--- /dev/null
+++ b/m4/codeset.m4
@@ -0,0 +1,24 @@
+# codeset.m4 serial 5 (gettext-0.18.2)
+dnl Copyright (C) 2000-2002, 2006, 2008-2014, 2016, 2019-2020 Free Software
+dnl Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl From Bruno Haible.
+
+AC_DEFUN([AM_LANGINFO_CODESET],
+[
+  AC_CACHE_CHECK([for nl_langinfo and CODESET], [am_cv_langinfo_codeset],
+    [AC_LINK_IFELSE(
+       [AC_LANG_PROGRAM(
+          [[#include <langinfo.h>]],
+          [[char* cs = nl_langinfo(CODESET); return !cs;]])],
+       [am_cv_langinfo_codeset=yes],
+       [am_cv_langinfo_codeset=no])
+    ])
+  if test $am_cv_langinfo_codeset = yes; then
+    AC_DEFINE([HAVE_LANGINFO_CODESET], [1],
+      [Define if you have <langinfo.h> and nl_langinfo(CODESET).])
+  fi
+])
diff --git a/m4/ctype.m4 b/m4/ctype.m4
new file mode 100644
index 0000000..0b123d5
--- /dev/null
+++ b/m4/ctype.m4
@@ -0,0 +1,32 @@
+# ctype_h.m4 serial 6
+dnl Copyright (C) 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_CTYPE_H],
+[
+  AC_REQUIRE([gl_CTYPE_H_DEFAULTS])
+
+  dnl <ctype.h> is always overridden, because of GNULIB_POSIXCHECK.
+  gl_NEXT_HEADERS([ctype.h])
+
+  dnl Check for declarations of anything we want to poison if the
+  dnl corresponding gnulib module is not in use.
+  gl_WARN_ON_USE_PREPARE([[#include <ctype.h>
+    ]], [isblank])
+])
+
+AC_DEFUN([gl_CTYPE_MODULE_INDICATOR],
+[
+  dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
+  AC_REQUIRE([gl_CTYPE_H_DEFAULTS])
+  gl_MODULE_INDICATOR_SET_VARIABLE([$1])
+])
+
+AC_DEFUN([gl_CTYPE_H_DEFAULTS],
+[
+  GNULIB_ISBLANK=0; AC_SUBST([GNULIB_ISBLANK])
+  dnl Assume proper GNU behavior unless another module says otherwise.
+  HAVE_ISBLANK=1;   AC_SUBST([HAVE_ISBLANK])
+])
diff --git a/m4/d-ino.m4 b/m4/d-ino.m4
new file mode 100644
index 0000000..64ce9ce
--- /dev/null
+++ b/m4/d-ino.m4
@@ -0,0 +1,60 @@
+# serial 20
+
+dnl From Jim Meyering.
+dnl
+dnl Check whether struct dirent has a member named d_ino.
+dnl
+
+# Copyright (C) 1997, 1999-2001, 2003-2004, 2006-2007, 2009-2020 Free Software
+# Foundation, Inc.
+
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_CHECK_TYPE_STRUCT_DIRENT_D_INO],
+  [AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+   AC_CACHE_CHECK([for d_ino member in directory struct],
+                  [gl_cv_struct_dirent_d_ino],
+     [AC_RUN_IFELSE(
+        [AC_LANG_PROGRAM(
+           [[#include <sys/types.h>
+             #include <sys/stat.h>
+             #include <dirent.h>
+           ]],
+           [[DIR *dp = opendir (".");
+             struct dirent *e;
+             struct stat st;
+             if (! dp)
+               return 1;
+             e = readdir (dp);
+             if (! e)
+               { closedir (dp); return 2; }
+             if (lstat (e->d_name, &st) != 0)
+               { closedir (dp); return 3; }
+             if (e->d_ino != st.st_ino)
+               { closedir (dp); return 4; }
+             closedir (dp);
+             return 0;
+           ]])],
+           [gl_cv_struct_dirent_d_ino=yes],
+           [gl_cv_struct_dirent_d_ino=no],
+           [case "$host_os" in
+                            # Guess yes on glibc systems with Linux kernel.
+              linux*-gnu*)  gl_cv_struct_dirent_d_ino="guessing yes" ;;
+                            # Guess yes on musl systems with Linux kernel.
+              linux*-musl*) gl_cv_struct_dirent_d_ino="guessing yes" ;;
+                            # Guess no on native Windows.
+              mingw*)       gl_cv_struct_dirent_d_ino="guessing no" ;;
+                            # If we don't know, obey --enable-cross-guesses.
+              *)            gl_cv_struct_dirent_d_ino="$gl_cross_guess_normal" ;;
+            esac
+           ])])
+   case "$gl_cv_struct_dirent_d_ino" in
+     *yes)
+       AC_DEFINE([D_INO_IN_DIRENT], [1],
+         [Define if struct dirent has a member d_ino that actually works.])
+       ;;
+   esac
+  ]
+)
diff --git a/m4/dirent_h.m4 b/m4/dirent_h.m4
new file mode 100644
index 0000000..8bef6a0
--- /dev/null
+++ b/m4/dirent_h.m4
@@ -0,0 +1,64 @@
+# dirent_h.m4 serial 16
+dnl Copyright (C) 2008-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl Written by Bruno Haible.
+
+AC_DEFUN([gl_DIRENT_H],
+[
+  dnl Use AC_REQUIRE here, so that the default behavior below is expanded
+  dnl once only, before all statements that occur in other macros.
+  AC_REQUIRE([gl_DIRENT_H_DEFAULTS])
+
+  dnl <dirent.h> is always overridden, because of GNULIB_POSIXCHECK.
+  gl_CHECK_NEXT_HEADERS([dirent.h])
+  if test $ac_cv_header_dirent_h = yes; then
+    HAVE_DIRENT_H=1
+  else
+    HAVE_DIRENT_H=0
+  fi
+  AC_SUBST([HAVE_DIRENT_H])
+
+  dnl Check for declarations of anything we want to poison if the
+  dnl corresponding gnulib module is not in use.
+  gl_WARN_ON_USE_PREPARE([[#include <dirent.h>
+    ]], [alphasort closedir dirfd fdopendir opendir readdir rewinddir scandir])
+])
+
+AC_DEFUN([gl_DIRENT_MODULE_INDICATOR],
+[
+  dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
+  AC_REQUIRE([gl_DIRENT_H_DEFAULTS])
+  gl_MODULE_INDICATOR_SET_VARIABLE([$1])
+  dnl Define it also as a C macro, for the benefit of the unit tests.
+  gl_MODULE_INDICATOR_FOR_TESTS([$1])
+])
+
+AC_DEFUN([gl_DIRENT_H_DEFAULTS],
+[
+  AC_REQUIRE([gl_UNISTD_H_DEFAULTS]) dnl for REPLACE_FCHDIR
+  GNULIB_OPENDIR=0;     AC_SUBST([GNULIB_OPENDIR])
+  GNULIB_READDIR=0;     AC_SUBST([GNULIB_READDIR])
+  GNULIB_REWINDDIR=0;   AC_SUBST([GNULIB_REWINDDIR])
+  GNULIB_CLOSEDIR=0;    AC_SUBST([GNULIB_CLOSEDIR])
+  GNULIB_DIRFD=0;       AC_SUBST([GNULIB_DIRFD])
+  GNULIB_FDOPENDIR=0;   AC_SUBST([GNULIB_FDOPENDIR])
+  GNULIB_SCANDIR=0;     AC_SUBST([GNULIB_SCANDIR])
+  GNULIB_ALPHASORT=0;   AC_SUBST([GNULIB_ALPHASORT])
+  dnl Assume proper GNU behavior unless another module says otherwise.
+  HAVE_OPENDIR=1;       AC_SUBST([HAVE_OPENDIR])
+  HAVE_READDIR=1;       AC_SUBST([HAVE_READDIR])
+  HAVE_REWINDDIR=1;     AC_SUBST([HAVE_REWINDDIR])
+  HAVE_CLOSEDIR=1;      AC_SUBST([HAVE_CLOSEDIR])
+  HAVE_DECL_DIRFD=1;    AC_SUBST([HAVE_DECL_DIRFD])
+  HAVE_DECL_FDOPENDIR=1;AC_SUBST([HAVE_DECL_FDOPENDIR])
+  HAVE_FDOPENDIR=1;     AC_SUBST([HAVE_FDOPENDIR])
+  HAVE_SCANDIR=1;       AC_SUBST([HAVE_SCANDIR])
+  HAVE_ALPHASORT=1;     AC_SUBST([HAVE_ALPHASORT])
+  REPLACE_OPENDIR=0;    AC_SUBST([REPLACE_OPENDIR])
+  REPLACE_CLOSEDIR=0;   AC_SUBST([REPLACE_CLOSEDIR])
+  REPLACE_DIRFD=0;      AC_SUBST([REPLACE_DIRFD])
+  REPLACE_FDOPENDIR=0;  AC_SUBST([REPLACE_FDOPENDIR])
+])
diff --git a/m4/dirfd.m4 b/m4/dirfd.m4
new file mode 100644
index 0000000..d92445e
--- /dev/null
+++ b/m4/dirfd.m4
@@ -0,0 +1,86 @@
+# serial 26   -*- Autoconf -*-
+
+dnl Find out how to get the file descriptor associated with an open DIR*.
+
+# Copyright (C) 2001-2006, 2008-2020 Free Software Foundation, Inc.
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+dnl From Jim Meyering
+
+AC_DEFUN([gl_FUNC_DIRFD],
+[
+  AC_REQUIRE([gl_DIRENT_H_DEFAULTS])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+
+  dnl Persuade glibc <dirent.h> to declare dirfd().
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
+
+  AC_CHECK_FUNCS([dirfd])
+  AC_CHECK_DECLS([dirfd], , ,
+    [[#include <sys/types.h>
+      #include <dirent.h>]])
+  if test $ac_cv_have_decl_dirfd = no; then
+    HAVE_DECL_DIRFD=0
+  fi
+
+  AC_CACHE_CHECK([whether dirfd is a macro],
+    [gl_cv_func_dirfd_macro],
+    [AC_EGREP_CPP([dirent_header_defines_dirfd], [
+#include <sys/types.h>
+#include <dirent.h>
+#ifdef dirfd
+ dirent_header_defines_dirfd
+#endif],
+       [gl_cv_func_dirfd_macro=yes],
+       [gl_cv_func_dirfd_macro=no])])
+
+  # Use the replacement if we have no function or macro with that name,
+  # or if OS/2 kLIBC whose dirfd() does not work.
+  # Replace only if the system declares dirfd already.
+  case $ac_cv_func_dirfd,$gl_cv_func_dirfd_macro,$host_os,$ac_cv_have_decl_dirfd in
+    no,no,*,yes | *,*,os2*,yes)
+      REPLACE_DIRFD=1
+      AC_DEFINE([REPLACE_DIRFD], [1],
+        [Define to 1 if gnulib's dirfd() replacement is used.]);;
+  esac
+])
+
+dnl Prerequisites of lib/dirfd.c.
+AC_DEFUN([gl_PREREQ_DIRFD],
+[
+  AC_CACHE_CHECK([how to get the file descriptor associated with an open DIR*],
+                 [gl_cv_sys_dir_fd_member_name],
+    [
+      dirfd_save_CFLAGS=$CFLAGS
+      for ac_expr in d_fd dd_fd; do
+
+        CFLAGS="$CFLAGS -DDIR_FD_MEMBER_NAME=$ac_expr"
+        AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
+           #include <sys/types.h>
+           #include <dirent.h>]],
+          [[DIR *dir_p = opendir("."); (void) dir_p->DIR_FD_MEMBER_NAME;]])],
+          [dir_fd_found=yes]
+        )
+        CFLAGS=$dirfd_save_CFLAGS
+        test "$dir_fd_found" = yes && break
+      done
+      test "$dir_fd_found" = yes || ac_expr=no_such_member
+
+      gl_cv_sys_dir_fd_member_name=$ac_expr
+    ]
+  )
+  if test $gl_cv_sys_dir_fd_member_name != no_such_member; then
+    AC_DEFINE_UNQUOTED([DIR_FD_MEMBER_NAME],
+      [$gl_cv_sys_dir_fd_member_name],
+      [the name of the file descriptor member of DIR])
+  fi
+  AH_VERBATIM([DIR_TO_FD],
+              [#ifdef DIR_FD_MEMBER_NAME
+# define DIR_TO_FD(Dir_p) ((Dir_p)->DIR_FD_MEMBER_NAME)
+#else
+# define DIR_TO_FD(Dir_p) -1
+#endif
+])
+])
diff --git a/m4/double-slash-root.m4 b/m4/double-slash-root.m4
new file mode 100644
index 0000000..c463ac4
--- /dev/null
+++ b/m4/double-slash-root.m4
@@ -0,0 +1,38 @@
+# double-slash-root.m4 serial 4   -*- Autoconf -*-
+dnl Copyright (C) 2006, 2008-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_DOUBLE_SLASH_ROOT],
+[
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  AC_CACHE_CHECK([whether // is distinct from /], [gl_cv_double_slash_root],
+    [ if test x"$cross_compiling" = xyes ; then
+        # When cross-compiling, there is no way to tell whether // is special
+        # short of a list of hosts.  However, the only known hosts to date
+        # that have a distinct // are Apollo DomainOS (too old to port to),
+        # Cygwin, and z/OS.  If anyone knows of another system for which // has
+        # special semantics and is distinct from /, please report it to
+        # <bug-gnulib@gnu.org>.
+        case $host in
+          *-cygwin | i370-ibm-openedition)
+            gl_cv_double_slash_root=yes ;;
+          *)
+            # Be optimistic and assume that / and // are the same when we
+            # don't know.
+            gl_cv_double_slash_root='unknown, assuming no' ;;
+        esac
+      else
+        set x `ls -di / // 2>/dev/null`
+        if test "$[2]" = "$[4]" && wc //dev/null >/dev/null 2>&1; then
+          gl_cv_double_slash_root=no
+        else
+          gl_cv_double_slash_root=yes
+        fi
+      fi])
+  if test "$gl_cv_double_slash_root" = yes; then
+    AC_DEFINE([DOUBLE_SLASH_IS_DISTINCT_ROOT], [1],
+      [Define to 1 if // is a file system root distinct from /.])
+  fi
+])
diff --git a/m4/dup.m4 b/m4/dup.m4
new file mode 100644
index 0000000..892de99
--- /dev/null
+++ b/m4/dup.m4
@@ -0,0 +1,54 @@
+# dup.m4 serial 7
+dnl Copyright (C) 2011-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_DUP],
+[
+  AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  m4_ifdef([gl_MSVC_INVAL], [
+    AC_REQUIRE([gl_MSVC_INVAL])
+    if test $HAVE_MSVC_INVALID_PARAMETER_HANDLER = 1; then
+      REPLACE_DUP=1
+    fi
+  ])
+  dnl Replace dup() for supporting the gnulib-defined fchdir() function,
+  dnl to keep fchdir's bookkeeping up-to-date.
+  m4_ifdef([gl_FUNC_FCHDIR], [
+    gl_TEST_FCHDIR
+    if test $HAVE_FCHDIR = 0; then
+      REPLACE_DUP=1
+    fi
+  ])
+  AC_CACHE_CHECK([whether dup works], [gl_cv_func_dup_works],
+    [AC_RUN_IFELSE(
+      [AC_LANG_PROGRAM([[#include <unistd.h>
+                         #include <fcntl.h>
+                         #include <errno.h>
+                       ]GL_MDA_DEFINES],
+         [[/* On OS/2 kLIBC, dup does not work on a directory fd.  */
+           int fd = open (".", O_RDONLY);
+           return fd < 0 ? 1 : dup (fd) < 0 ? 2 : 0;
+         ]])
+      ],
+      [gl_cv_func_dup_works=yes],
+      [gl_cv_func_dup_works=no],
+      [case "$host_os" in
+                 # Guess no on native Windows.
+         mingw*) gl_cv_func_dup_works="guessing no" ;;
+         *)      gl_cv_func_dup_works="guessing yes" ;;
+       esac
+      ])
+    ])
+  case "$gl_cv_func_dup_works" in
+    *yes) ;;
+    *)
+      REPLACE_DUP=1
+      ;;
+  esac
+])
+
+# Prerequisites of lib/dup.c.
+AC_DEFUN([gl_PREREQ_DUP], [:])
diff --git a/m4/dup2.m4 b/m4/dup2.m4
new file mode 100644
index 0000000..a82798d
--- /dev/null
+++ b/m4/dup2.m4
@@ -0,0 +1,105 @@
+#serial 27
+dnl Copyright (C) 2002, 2005, 2007, 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_DUP2],
+[
+  AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  AC_CACHE_CHECK([whether dup2 works], [gl_cv_func_dup2_works],
+    [AC_RUN_IFELSE([
+       AC_LANG_PROGRAM(
+         [[#include <errno.h>
+           #include <fcntl.h>
+           #include <limits.h>
+           #include <sys/resource.h>
+           #include <unistd.h>
+           ]GL_MDA_DEFINES[
+           #ifndef RLIM_SAVED_CUR
+           # define RLIM_SAVED_CUR RLIM_INFINITY
+           #endif
+           #ifndef RLIM_SAVED_MAX
+           # define RLIM_SAVED_MAX RLIM_INFINITY
+           #endif
+         ]],
+         [[int result = 0;
+           int bad_fd = INT_MAX;
+           struct rlimit rlim;
+           if (getrlimit (RLIMIT_NOFILE, &rlim) == 0
+               && 0 <= rlim.rlim_cur && rlim.rlim_cur <= INT_MAX
+               && rlim.rlim_cur != RLIM_INFINITY
+               && rlim.rlim_cur != RLIM_SAVED_MAX
+               && rlim.rlim_cur != RLIM_SAVED_CUR)
+             bad_fd = rlim.rlim_cur;
+           #ifdef FD_CLOEXEC
+             if (fcntl (1, F_SETFD, FD_CLOEXEC) == -1)
+               result |= 1;
+           #endif
+           if (dup2 (1, 1) != 1)
+             result |= 2;
+           #ifdef FD_CLOEXEC
+             if (fcntl (1, F_GETFD) != FD_CLOEXEC)
+               result |= 4;
+           #endif
+           close (0);
+           if (dup2 (0, 0) != -1)
+             result |= 8;
+           /* Many gnulib modules require POSIX conformance of EBADF.  */
+           if (dup2 (2, bad_fd) == -1 && errno != EBADF)
+             result |= 16;
+           /* Flush out some cygwin core dumps.  */
+           if (dup2 (2, -1) != -1 || errno != EBADF)
+             result |= 32;
+           dup2 (2, 255);
+           dup2 (2, 256);
+           /* On OS/2 kLIBC, dup2() does not work on a directory fd.  */
+           {
+             int fd = open (".", O_RDONLY);
+             if (fd == -1)
+               result |= 64;
+             else if (dup2 (fd, fd + 1) == -1)
+               result |= 128;
+             close (fd);
+           }
+           return result;]])
+      ],
+      [gl_cv_func_dup2_works=yes], [gl_cv_func_dup2_works=no],
+      [case "$host_os" in
+         mingw*) # on this platform, dup2 always returns 0 for success
+           gl_cv_func_dup2_works="guessing no" ;;
+         cygwin*) # on cygwin 1.5.x, dup2(1,1) returns 0
+           gl_cv_func_dup2_works="guessing no" ;;
+         aix* | freebsd*)
+                 # on AIX 7.1 and FreeBSD 6.1, dup2 (1,toobig) gives EMFILE,
+                 # not EBADF.
+           gl_cv_func_dup2_works="guessing no" ;;
+         haiku*) # on Haiku alpha 2, dup2(1, 1) resets FD_CLOEXEC.
+           gl_cv_func_dup2_works="guessing no" ;;
+         *-android*) # implemented using dup3(), which fails if oldfd == newfd
+           gl_cv_func_dup2_works="guessing no" ;;
+         os2*) # on OS/2 kLIBC, dup2() does not work on a directory fd.
+           gl_cv_func_dup2_works="guessing no" ;;
+         *) gl_cv_func_dup2_works="guessing yes" ;;
+       esac])
+    ])
+  case "$gl_cv_func_dup2_works" in
+    *yes) ;;
+    *)
+      REPLACE_DUP2=1
+      AC_CHECK_FUNCS([setdtablesize])
+      ;;
+  esac
+  dnl Replace dup2() for supporting the gnulib-defined fchdir() function,
+  dnl to keep fchdir's bookkeeping up-to-date.
+  m4_ifdef([gl_FUNC_FCHDIR], [
+    gl_TEST_FCHDIR
+    if test $HAVE_FCHDIR = 0; then
+      REPLACE_DUP2=1
+    fi
+  ])
+])
+
+# Prerequisites of lib/dup2.c.
+AC_DEFUN([gl_PREREQ_DUP2], [])
diff --git a/m4/eaccess.m4 b/m4/eaccess.m4
new file mode 100644
index 0000000..7eea8e9
--- /dev/null
+++ b/m4/eaccess.m4
@@ -0,0 +1,12 @@
+# eaccess.m4 serial 2
+dnl Copyright (C) 2003, 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_EACCESS],
+[
+  AC_CHECK_FUNC([eaccess], ,
+    [AC_DEFINE([eaccess], [access],
+       [Define as 'access' if you don't have the eaccess() function.])])
+])
diff --git a/m4/eealloc.m4 b/m4/eealloc.m4
new file mode 100644
index 0000000..236f373
--- /dev/null
+++ b/m4/eealloc.m4
@@ -0,0 +1,31 @@
+# eealloc.m4 serial 3
+dnl Copyright (C) 2003, 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_EEALLOC],
+[
+  AC_REQUIRE([gl_EEMALLOC])
+  AC_REQUIRE([gl_EEREALLOC])
+])
+
+AC_DEFUN([gl_EEMALLOC],
+[
+  _AC_FUNC_MALLOC_IF(
+    [gl_cv_func_malloc_0_nonnull=1],
+    [gl_cv_func_malloc_0_nonnull=0])
+  AC_DEFINE_UNQUOTED([MALLOC_0_IS_NONNULL], [$gl_cv_func_malloc_0_nonnull],
+    [If malloc(0) is != NULL, define this to 1.  Otherwise define this
+     to 0.])
+])
+
+AC_DEFUN([gl_EEREALLOC],
+[
+  _AC_FUNC_REALLOC_IF(
+    [gl_cv_func_realloc_0_nonnull=1],
+    [gl_cv_func_realloc_0_nonnull=0])
+  AC_DEFINE_UNQUOTED([REALLOC_0_IS_NONNULL], [$gl_cv_func_realloc_0_nonnull],
+    [If realloc(NULL,0) is != NULL, define this to 1.  Otherwise define this
+     to 0.])
+])
diff --git a/m4/environ.m4 b/m4/environ.m4
new file mode 100644
index 0000000..bab85f1
--- /dev/null
+++ b/m4/environ.m4
@@ -0,0 +1,45 @@
+# environ.m4 serial 7
+dnl Copyright (C) 2001-2004, 2006-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN_ONCE([gl_ENVIRON],
+[
+  AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
+  dnl Persuade glibc <unistd.h> to declare environ.
+  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+
+  AC_CHECK_HEADERS_ONCE([unistd.h])
+  gt_CHECK_VAR_DECL(
+    [#if HAVE_UNISTD_H
+     #include <unistd.h>
+     #endif
+     /* mingw, BeOS, Haiku declare environ in <stdlib.h>, not in <unistd.h>.  */
+     #include <stdlib.h>
+    ],
+    [environ])
+  if test $gt_cv_var_environ_declaration != yes; then
+    HAVE_DECL_ENVIRON=0
+  fi
+])
+
+# Check if a variable is properly declared.
+# gt_CHECK_VAR_DECL(includes,variable)
+AC_DEFUN([gt_CHECK_VAR_DECL],
+[
+  define([gt_cv_var], [gt_cv_var_]$2[_declaration])
+  AC_CACHE_CHECK([if $2 is properly declared], [gt_cv_var],
+    [AC_COMPILE_IFELSE(
+       [AC_LANG_PROGRAM(
+          [[$1
+            extern struct { int foo; } $2;]],
+          [[$2.foo = 1;]])],
+       [gt_cv_var=no],
+       [gt_cv_var=yes])])
+  if test $gt_cv_var = yes; then
+    AC_DEFINE([HAVE_]m4_translit($2, [a-z], [A-Z])[_DECL], 1,
+              [Define if you have the declaration of $2.])
+  fi
+  undefine([gt_cv_var])
+])
diff --git a/m4/errno_h.m4 b/m4/errno_h.m4
new file mode 100644
index 0000000..dd4994f
--- /dev/null
+++ b/m4/errno_h.m4
@@ -0,0 +1,133 @@
+# errno_h.m4 serial 13
+dnl Copyright (C) 2004, 2006, 2008-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_PREREQ([2.61])
+
+AC_DEFUN_ONCE([gl_HEADER_ERRNO_H],
+[
+  AC_REQUIRE([AC_PROG_CC])
+  AC_CACHE_CHECK([for complete errno.h], [gl_cv_header_errno_h_complete], [
+    AC_EGREP_CPP([booboo],[
+#include <errno.h>
+#if !defined ETXTBSY
+booboo
+#endif
+#if !defined ENOMSG
+booboo
+#endif
+#if !defined EIDRM
+booboo
+#endif
+#if !defined ENOLINK
+booboo
+#endif
+#if !defined EPROTO
+booboo
+#endif
+#if !defined EMULTIHOP
+booboo
+#endif
+#if !defined EBADMSG
+booboo
+#endif
+#if !defined EOVERFLOW
+booboo
+#endif
+#if !defined ENOTSUP
+booboo
+#endif
+#if !defined ENETRESET
+booboo
+#endif
+#if !defined ECONNABORTED
+booboo
+#endif
+#if !defined ESTALE
+booboo
+#endif
+#if !defined EDQUOT
+booboo
+#endif
+#if !defined ECANCELED
+booboo
+#endif
+#if !defined EOWNERDEAD
+booboo
+#endif
+#if !defined ENOTRECOVERABLE
+booboo
+#endif
+#if !defined EILSEQ
+booboo
+#endif
+      ],
+      [gl_cv_header_errno_h_complete=no],
+      [gl_cv_header_errno_h_complete=yes])
+  ])
+  if test $gl_cv_header_errno_h_complete = yes; then
+    ERRNO_H=''
+  else
+    gl_NEXT_HEADERS([errno.h])
+    ERRNO_H='errno.h'
+  fi
+  AC_SUBST([ERRNO_H])
+  AM_CONDITIONAL([GL_GENERATE_ERRNO_H], [test -n "$ERRNO_H"])
+  gl_REPLACE_ERRNO_VALUE([EMULTIHOP])
+  gl_REPLACE_ERRNO_VALUE([ENOLINK])
+  gl_REPLACE_ERRNO_VALUE([EOVERFLOW])
+])
+
+# Assuming $1 = EOVERFLOW.
+# The EOVERFLOW errno value ought to be defined in <errno.h>, according to
+# POSIX.  But some systems (like OpenBSD 4.0 or AIX 3) don't define it, and
+# some systems (like OSF/1) define it when _XOPEN_SOURCE_EXTENDED is defined.
+# Check for the value of EOVERFLOW.
+# Set the variables EOVERFLOW_HIDDEN and EOVERFLOW_VALUE.
+AC_DEFUN([gl_REPLACE_ERRNO_VALUE],
+[
+  if test -n "$ERRNO_H"; then
+    AC_CACHE_CHECK([for ]$1[ value], [gl_cv_header_errno_h_]$1, [
+      AC_EGREP_CPP([yes],[
+#include <errno.h>
+#ifdef ]$1[
+yes
+#endif
+      ],
+      [gl_cv_header_errno_h_]$1[=yes],
+      [gl_cv_header_errno_h_]$1[=no])
+      if test $gl_cv_header_errno_h_]$1[ = no; then
+        AC_EGREP_CPP([yes],[
+#define _XOPEN_SOURCE_EXTENDED 1
+#include <errno.h>
+#ifdef ]$1[
+yes
+#endif
+          ], [gl_cv_header_errno_h_]$1[=hidden])
+        if test $gl_cv_header_errno_h_]$1[ = hidden; then
+          dnl The macro exists but is hidden.
+          dnl Define it to the same value.
+          AC_COMPUTE_INT([gl_cv_header_errno_h_]$1, $1, [
+#define _XOPEN_SOURCE_EXTENDED 1
+#include <errno.h>
+/* The following two lines are a workaround against an autoconf-2.52 bug.  */
+#include <stdio.h>
+#include <stdlib.h>
+])
+        fi
+      fi
+    ])
+    case $gl_cv_header_errno_h_]$1[ in
+      yes | no)
+        ]$1[_HIDDEN=0; ]$1[_VALUE=
+        ;;
+      *)
+        ]$1[_HIDDEN=1; ]$1[_VALUE="$gl_cv_header_errno_h_]$1["
+        ;;
+    esac
+    AC_SUBST($1[_HIDDEN])
+    AC_SUBST($1[_VALUE])
+  fi
+])
diff --git a/m4/error.m4 b/m4/error.m4
new file mode 100644
index 0000000..60c229d
--- /dev/null
+++ b/m4/error.m4
@@ -0,0 +1,27 @@
+#serial 14
+
+# Copyright (C) 1996-1998, 2001-2004, 2009-2020 Free Software Foundation, Inc.
+#
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_ERROR],
+[
+  dnl We don't use AC_FUNC_ERROR_AT_LINE any more, because it is no longer
+  dnl maintained in Autoconf and because it invokes AC_LIBOBJ.
+  AC_CACHE_CHECK([for error_at_line], [ac_cv_lib_error_at_line],
+    [AC_LINK_IFELSE(
+       [AC_LANG_PROGRAM(
+          [[#include <error.h>]],
+          [[error_at_line (0, 0, "", 0, "an error occurred");]])],
+       [ac_cv_lib_error_at_line=yes],
+       [ac_cv_lib_error_at_line=no])])
+])
+
+# Prerequisites of lib/error.c.
+AC_DEFUN([gl_PREREQ_ERROR],
+[
+  AC_REQUIRE([AC_FUNC_STRERROR_R])
+  :
+])
diff --git a/m4/exponentd.m4 b/m4/exponentd.m4
new file mode 100644
index 0000000..cca8797
--- /dev/null
+++ b/m4/exponentd.m4
@@ -0,0 +1,116 @@
+# exponentd.m4 serial 3
+dnl Copyright (C) 2007-2008, 2010-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+AC_DEFUN([gl_DOUBLE_EXPONENT_LOCATION],
+[
+  AC_CACHE_CHECK([where to find the exponent in a 'double'],
+    [gl_cv_cc_double_expbit0],
+    [
+      AC_RUN_IFELSE(
+        [AC_LANG_SOURCE([[
+#include <float.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <string.h>
+#define NWORDS \
+  ((sizeof (double) + sizeof (unsigned int) - 1) / sizeof (unsigned int))
+typedef union { double value; unsigned int word[NWORDS]; } memory_double;
+static unsigned int ored_words[NWORDS];
+static unsigned int anded_words[NWORDS];
+static void add_to_ored_words (double x)
+{
+  memory_double m;
+  size_t i;
+  /* Clear it first, in case sizeof (double) < sizeof (memory_double).  */
+  memset (&m, 0, sizeof (memory_double));
+  m.value = x;
+  for (i = 0; i < NWORDS; i++)
+    {
+      ored_words[i] |= m.word[i];
+      anded_words[i] &= m.word[i];
+    }
+}
+int main ()
+{
+  size_t j;
+  FILE *fp = fopen ("conftest.out", "w");
+  if (fp == NULL)
+    return 1;
+  for (j = 0; j < NWORDS; j++)
+    anded_words[j] = ~ (unsigned int) 0;
+  add_to_ored_words (0.25);
+  add_to_ored_words (0.5);
+  add_to_ored_words (1.0);
+  add_to_ored_words (2.0);
+  add_to_ored_words (4.0);
+  /* Remove bits that are common (e.g. if representation of the first mantissa
+     bit is explicit).  */
+  for (j = 0; j < NWORDS; j++)
+    ored_words[j] &= ~anded_words[j];
+  /* Now find the nonzero word.  */
+  for (j = 0; j < NWORDS; j++)
+    if (ored_words[j] != 0)
+      break;
+  if (j < NWORDS)
+    {
+      size_t i;
+      for (i = j + 1; i < NWORDS; i++)
+        if (ored_words[i] != 0)
+          {
+            fprintf (fp, "unknown");
+            return (fclose (fp) != 0);
+          }
+      for (i = 0; ; i++)
+        if ((ored_words[j] >> i) & 1)
+          {
+            fprintf (fp, "word %d bit %d", (int) j, (int) i);
+            return (fclose (fp) != 0);
+          }
+    }
+  fprintf (fp, "unknown");
+  return (fclose (fp) != 0);
+}
+        ]])],
+        [gl_cv_cc_double_expbit0=`cat conftest.out`],
+        [gl_cv_cc_double_expbit0="unknown"],
+        [
+          dnl On ARM, there are two 'double' floating-point formats, used by
+          dnl different sets of instructions: The older FPA instructions assume
+          dnl that they are stored in big-endian word order, while the words
+          dnl (like integer types) are stored in little-endian byte order.
+          dnl The newer VFP instructions assume little-endian order
+          dnl consistently.
+          AC_EGREP_CPP([mixed_endianness], [
+#if defined arm || defined __arm || defined __arm__
+  mixed_endianness
+#endif
+            ],
+            [gl_cv_cc_double_expbit0="unknown"],
+            [
+              pushdef([AC_MSG_CHECKING],[:])dnl
+              pushdef([AC_MSG_RESULT],[:])dnl
+              pushdef([AC_MSG_RESULT_UNQUOTED],[:])dnl
+              AC_C_BIGENDIAN(
+                [gl_cv_cc_double_expbit0="word 0 bit 20"],
+                [gl_cv_cc_double_expbit0="word 1 bit 20"],
+                [gl_cv_cc_double_expbit0="unknown"])
+              popdef([AC_MSG_RESULT_UNQUOTED])dnl
+              popdef([AC_MSG_RESULT])dnl
+              popdef([AC_MSG_CHECKING])dnl
+            ])
+        ])
+      rm -f conftest.out
+    ])
+  case "$gl_cv_cc_double_expbit0" in
+    word*bit*)
+      word=`echo "$gl_cv_cc_double_expbit0" | sed -e 's/word //' -e 's/ bit.*//'`
+      bit=`echo "$gl_cv_cc_double_expbit0" | sed -e 's/word.*bit //'`
+      AC_DEFINE_UNQUOTED([DBL_EXPBIT0_WORD], [$word],
+        [Define as the word index where to find the exponent of 'double'.])
+      AC_DEFINE_UNQUOTED([DBL_EXPBIT0_BIT], [$bit],
+        [Define as the bit index in the word where to find bit 0 of the exponent of 'double'.])
+      ;;
+  esac
+])
diff --git a/m4/extensions.m4 b/m4/extensions.m4
new file mode 100644
index 0000000..44be1d1
--- /dev/null
+++ b/m4/extensions.m4
@@ -0,0 +1,215 @@
+# serial 21  -*- Autoconf -*-
+# Enable extensions on systems that normally disable them.
+
+# Copyright (C) 2003, 2006-2020 Free Software Foundation, Inc.
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+dnl Define to empty for the benefit of Autoconf 2.69 and earlier, so that
+dnl AC_USE_SYSTEM_EXTENSIONS (below) can be used unchanged from Autoconf 2.70+.
+m4_ifndef([AC_CHECK_INCLUDES_DEFAULT],
+  [AC_DEFUN([AC_CHECK_INCLUDES_DEFAULT], [])])
+
+# This definition of AC_USE_SYSTEM_EXTENSIONS is stolen from git
+# Autoconf.  Perhaps we can remove this once we can assume Autoconf
+# is recent-enough everywhere, but since Autoconf mutates rapidly
+# enough in this area it's likely we'll need to redefine
+# AC_USE_SYSTEM_EXTENSIONS for quite some time.
+
+# If autoconf reports a warning
+#     warning: AC_COMPILE_IFELSE was called before AC_USE_SYSTEM_EXTENSIONS
+# or  warning: AC_RUN_IFELSE was called before AC_USE_SYSTEM_EXTENSIONS
+# the fix is
+#   1) to ensure that AC_USE_SYSTEM_EXTENSIONS is never directly invoked
+#      but always AC_REQUIREd,
+#   2) to ensure that for each occurrence of
+#        AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
+#      or
+#        AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+#      the corresponding gnulib module description has 'extensions' among
+#      its dependencies. This will ensure that the gl_USE_SYSTEM_EXTENSIONS
+#      invocation occurs in gl_EARLY, not in gl_INIT.
+
+m4_version_prereq([2.70.1], [], [
+
+# AC_USE_SYSTEM_EXTENSIONS
+# ------------------------
+# Enable extensions on systems that normally disable them,
+# typically due to standards-conformance issues.
+# We unconditionally define as many of the known feature-enabling
+# as possible, reserving conditional behavior for macros that are
+# known to cause problems on some platforms (such as __EXTENSIONS__).
+AC_DEFUN_ONCE([AC_USE_SYSTEM_EXTENSIONS],
+[AC_BEFORE([$0], [AC_PREPROC_IFELSE])dnl
+AC_BEFORE([$0], [AC_COMPILE_IFELSE])dnl
+AC_BEFORE([$0], [AC_LINK_IFELSE])dnl
+AC_BEFORE([$0], [AC_RUN_IFELSE])dnl
+AC_BEFORE([$0], [AC_CHECK_INCLUDES_DEFAULT])dnl
+dnl #undef in AH_VERBATIM gets replaced with #define by AC_DEFINE.
+dnl Use a different key than __EXTENSIONS__, as that name broke existing
+dnl configure.ac when using autoheader 2.62.
+dnl The macros below are in alphabetical order ignoring leading _ or __
+dnl prefixes.
+AH_VERBATIM([USE_SYSTEM_EXTENSIONS],
+[/* Enable extensions on AIX 3, Interix.  */
+#ifndef _ALL_SOURCE
+# undef _ALL_SOURCE
+#endif
+/* Enable general extensions on macOS.  */
+#ifndef _DARWIN_C_SOURCE
+# undef _DARWIN_C_SOURCE
+#endif
+/* Enable general extensions on Solaris.  */
+#ifndef __EXTENSIONS__
+# undef __EXTENSIONS__
+#endif
+/* Enable GNU extensions on systems that have them.  */
+#ifndef _GNU_SOURCE
+# undef _GNU_SOURCE
+#endif
+/* Enable X/Open compliant socket functions that do not require linking
+   with -lxnet on HP-UX 11.11.  */
+#ifndef _HPUX_ALT_XOPEN_SOCKET_API
+# undef _HPUX_ALT_XOPEN_SOCKET_API
+#endif
+/* Identify the host operating system as Minix.
+   This macro does not affect the system headers' behavior.
+   A future release of Autoconf may stop defining this macro.  */
+#ifndef _MINIX
+# undef _MINIX
+#endif
+/* Enable general extensions on NetBSD.
+   Enable NetBSD compatibility extensions on Minix.  */
+#ifndef _NETBSD_SOURCE
+# undef _NETBSD_SOURCE
+#endif
+/* Enable OpenBSD compatibility extensions on NetBSD.
+   Oddly enough, this does nothing on OpenBSD.  */
+#ifndef _OPENBSD_SOURCE
+# undef _OPENBSD_SOURCE
+#endif
+/* Define to 1 if needed for POSIX-compatible behavior.  */
+#ifndef _POSIX_SOURCE
+# undef _POSIX_SOURCE
+#endif
+/* Define to 2 if needed for POSIX-compatible behavior.  */
+#ifndef _POSIX_1_SOURCE
+# undef _POSIX_1_SOURCE
+#endif
+/* Enable POSIX-compatible threading on Solaris.  */
+#ifndef _POSIX_PTHREAD_SEMANTICS
+# undef _POSIX_PTHREAD_SEMANTICS
+#endif
+/* Enable extensions specified by ISO/IEC TS 18661-5:2014.  */
+#ifndef __STDC_WANT_IEC_60559_ATTRIBS_EXT__
+# undef __STDC_WANT_IEC_60559_ATTRIBS_EXT__
+#endif
+/* Enable extensions specified by ISO/IEC TS 18661-1:2014.  */
+#ifndef __STDC_WANT_IEC_60559_BFP_EXT__
+# undef __STDC_WANT_IEC_60559_BFP_EXT__
+#endif
+/* Enable extensions specified by ISO/IEC TS 18661-2:2015.  */
+#ifndef __STDC_WANT_IEC_60559_DFP_EXT__
+# undef __STDC_WANT_IEC_60559_DFP_EXT__
+#endif
+/* Enable extensions specified by ISO/IEC TS 18661-4:2015.  */
+#ifndef __STDC_WANT_IEC_60559_FUNCS_EXT__
+# undef __STDC_WANT_IEC_60559_FUNCS_EXT__
+#endif
+/* Enable extensions specified by ISO/IEC TS 18661-3:2015.  */
+#ifndef __STDC_WANT_IEC_60559_TYPES_EXT__
+# undef __STDC_WANT_IEC_60559_TYPES_EXT__
+#endif
+/* Enable extensions specified by ISO/IEC TR 24731-2:2010.  */
+#ifndef __STDC_WANT_LIB_EXT2__
+# undef __STDC_WANT_LIB_EXT2__
+#endif
+/* Enable extensions specified by ISO/IEC 24747:2009.  */
+#ifndef __STDC_WANT_MATH_SPEC_FUNCS__
+# undef __STDC_WANT_MATH_SPEC_FUNCS__
+#endif
+/* Enable extensions on HP NonStop.  */
+#ifndef _TANDEM_SOURCE
+# undef _TANDEM_SOURCE
+#endif
+/* Enable X/Open extensions.  Define to 500 only if necessary
+   to make mbstate_t available.  */
+#ifndef _XOPEN_SOURCE
+# undef _XOPEN_SOURCE
+#endif
+])dnl
+
+  AC_REQUIRE([AC_CHECK_INCLUDES_DEFAULT])dnl
+  _AC_CHECK_HEADER_ONCE([wchar.h])
+  _AC_CHECK_HEADER_ONCE([minix/config.h])
+
+dnl Defining __EXTENSIONS__ may break the system headers on some systems.
+dnl (FIXME: Which ones?)
+  AC_CACHE_CHECK([whether it is safe to define __EXTENSIONS__],
+    [ac_cv_safe_to_define___extensions__],
+    [AC_COMPILE_IFELSE(
+       [AC_LANG_PROGRAM([[
+#         define __EXTENSIONS__ 1
+          ]AC_INCLUDES_DEFAULT])],
+       [ac_cv_safe_to_define___extensions__=yes],
+       [ac_cv_safe_to_define___extensions__=no])])
+
+dnl HP-UX 11.11 defines mbstate_t only if _XOPEN_SOURCE is defined to
+dnl 500, regardless of whether compiling with -Ae or -D_HPUX_SOURCE=1.
+dnl But defining _XOPEN_SOURCE may turn *off* extensions on platforms
+dnl not covered by turn-on-extensions macros (notably Dragonfly, Free,
+dnl and OpenBSD, which don't have any equivalent of _NETBSD_SOURCE) so
+dnl it should only be defined when necessary.
+  AC_CACHE_CHECK([whether _XOPEN_SOURCE should be defined],
+    [ac_cv_should_define__xopen_source],
+    [ac_cv_should_define__xopen_source=no
+    AS_IF([test $ac_cv_header_wchar_h = yes],
+      [AC_COMPILE_IFELSE(
+        [AC_LANG_PROGRAM([[
+          #include <wchar.h>
+          mbstate_t x;]])],
+        [],
+        [AC_COMPILE_IFELSE(
+          [AC_LANG_PROGRAM([[
+            #define _XOPEN_SOURCE 500
+            #include <wchar.h>
+            mbstate_t x;]])],
+          [ac_cv_should_define__xopen_source=yes])])])])
+
+  AC_DEFINE([_ALL_SOURCE])
+  AC_DEFINE([_DARWIN_C_SOURCE])
+  AC_DEFINE([_GNU_SOURCE])
+  AC_DEFINE([_HPUX_ALT_XOPEN_SOCKET_API])
+  AC_DEFINE([_NETBSD_SOURCE])
+  AC_DEFINE([_OPENBSD_SOURCE])
+  AC_DEFINE([_POSIX_PTHREAD_SEMANTICS])
+  AC_DEFINE([__STDC_WANT_IEC_60559_ATTRIBS_EXT__])
+  AC_DEFINE([__STDC_WANT_IEC_60559_BFP_EXT__])
+  AC_DEFINE([__STDC_WANT_IEC_60559_DFP_EXT__])
+  AC_DEFINE([__STDC_WANT_IEC_60559_FUNCS_EXT__])
+  AC_DEFINE([__STDC_WANT_IEC_60559_TYPES_EXT__])
+  AC_DEFINE([__STDC_WANT_LIB_EXT2__])
+  AC_DEFINE([__STDC_WANT_MATH_SPEC_FUNCS__])
+  AC_DEFINE([_TANDEM_SOURCE])
+  AS_IF([test $ac_cv_header_minix_config_h = yes],
+    [MINIX=yes
+    AC_DEFINE([_MINIX])
+    AC_DEFINE([_POSIX_SOURCE])
+    AC_DEFINE([_POSIX_1_SOURCE], [2])],
+    [MINIX=])
+  AS_IF([test $ac_cv_safe_to_define___extensions__ = yes],
+    [AC_DEFINE([__EXTENSIONS__])])
+  AS_IF([test $ac_cv_should_define__xopen_source = yes],
+    [AC_DEFINE([_XOPEN_SOURCE], [500])])
+])# AC_USE_SYSTEM_EXTENSIONS
+])
+
+# gl_USE_SYSTEM_EXTENSIONS
+# ------------------------
+# Enable extensions on systems that normally disable them,
+# typically due to standards-conformance issues.
+AC_DEFUN_ONCE([gl_USE_SYSTEM_EXTENSIONS],
+[
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
+])
diff --git a/m4/extern-inline.m4 b/m4/extern-inline.m4
new file mode 100644
index 0000000..7f1bb39
--- /dev/null
+++ b/m4/extern-inline.m4
@@ -0,0 +1,99 @@
+dnl 'extern inline' a la ISO C99.
+
+dnl Copyright 2012-2014 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_EXTERN_INLINE],
+[
+  AH_VERBATIM([extern_inline],
+[/* Please see the Gnulib manual for how to use these macros.
+
+   Suppress extern inline with HP-UX cc, as it appears to be broken; see
+   <http://lists.gnu.org/archive/html/bug-texinfo/2013-02/msg00030.html>.
+
+   Suppress extern inline with Sun C in standards-conformance mode, as it
+   mishandles inline functions that call each other.  E.g., for 'inline void f
+   (void) { } inline void g (void) { f (); }', c99 incorrectly complains
+   'reference to static identifier "f" in extern inline function'.
+   This bug was observed with Sun C 5.12 SunOS_i386 2011/11/16.
+
+   Suppress extern inline (with or without __attribute__ ((__gnu_inline__)))
+   on configurations that mistakenly use 'static inline' to implement
+   functions or macros in standard C headers like <ctype.h>.  For example,
+   if isdigit is mistakenly implemented via a static inline function,
+   a program containing an extern inline function that calls isdigit
+   may not work since the C standard prohibits extern inline functions
+   from calling static functions.  This bug is known to occur on:
+
+     OS X 10.8 and earlier; see:
+     http://lists.gnu.org/archive/html/bug-gnulib/2012-12/msg00023.html
+
+     DragonFly; see
+     http://muscles.dragonflybsd.org/bulk/bleeding-edge-potential/latest-per-pkg/ah-tty-0.3.12.log
+
+     FreeBSD; see:
+     http://lists.gnu.org/archive/html/bug-gnulib/2014-07/msg00104.html
+
+   OS X 10.9 has a macro __header_inline indicating the bug is fixed for C and
+   for clang but remains for g++; see <http://trac.macports.org/ticket/41033>.
+   Assume DragonFly and FreeBSD will be similar.  */
+#if (((defined __APPLE__ && defined __MACH__) \
+      || defined __DragonFly__ || defined __FreeBSD__) \
+     && (defined __header_inline \
+         ? (defined __cplusplus && defined __GNUC_STDC_INLINE__ \
+            && ! defined __clang__) \
+         : ((! defined _DONT_USE_CTYPE_INLINE_ \
+             && (defined __GNUC__ || defined __cplusplus)) \
+            || (defined _FORTIFY_SOURCE && 0 < _FORTIFY_SOURCE \
+                && defined __GNUC__ && ! defined __cplusplus))))
+# define _GL_EXTERN_INLINE_STDHEADER_BUG
+#endif
+#if ((__GNUC__ \
+      ? defined __GNUC_STDC_INLINE__ && __GNUC_STDC_INLINE__ \
+      : (199901L <= __STDC_VERSION__ \
+         && !defined __HP_cc \
+         && !(defined __SUNPRO_C && __STDC__))) \
+     && !defined _GL_EXTERN_INLINE_STDHEADER_BUG)
+# define _GL_INLINE inline
+# define _GL_EXTERN_INLINE extern inline
+# define _GL_EXTERN_INLINE_IN_USE
+#elif (2 < __GNUC__ + (7 <= __GNUC_MINOR__) && !defined __STRICT_ANSI__ \
+       && !defined _GL_EXTERN_INLINE_STDHEADER_BUG)
+# if defined __GNUC_GNU_INLINE__ && __GNUC_GNU_INLINE__
+   /* __gnu_inline__ suppresses a GCC 4.2 diagnostic.  */
+#  define _GL_INLINE extern inline __attribute__ ((__gnu_inline__))
+# else
+#  define _GL_INLINE extern inline
+# endif
+# define _GL_EXTERN_INLINE extern
+# define _GL_EXTERN_INLINE_IN_USE
+#else
+# define _GL_INLINE static _GL_UNUSED
+# define _GL_EXTERN_INLINE static _GL_UNUSED
+#endif
+
+#if 4 < __GNUC__ + (6 <= __GNUC_MINOR__)
+# if defined __GNUC_STDC_INLINE__ && __GNUC_STDC_INLINE__
+#  define _GL_INLINE_HEADER_CONST_PRAGMA
+# else
+#  define _GL_INLINE_HEADER_CONST_PRAGMA \
+     _Pragma ("GCC diagnostic ignored \"-Wsuggest-attribute=const\"")
+# endif
+  /* Suppress GCC's bogus "no previous prototype for 'FOO'"
+     and "no previous declaration for 'FOO'"  diagnostics,
+     when FOO is an inline function in the header; see
+     <http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54113>.  */
+# define _GL_INLINE_HEADER_BEGIN \
+    _Pragma ("GCC diagnostic push") \
+    _Pragma ("GCC diagnostic ignored \"-Wmissing-prototypes\"") \
+    _Pragma ("GCC diagnostic ignored \"-Wmissing-declarations\"") \
+    _GL_INLINE_HEADER_CONST_PRAGMA
+# define _GL_INLINE_HEADER_END \
+    _Pragma ("GCC diagnostic pop")
+#else
+# define _GL_INLINE_HEADER_BEGIN
+# define _GL_INLINE_HEADER_END
+#endif])
+])
diff --git a/m4/fatal-signal.m4 b/m4/fatal-signal.m4
new file mode 100644
index 0000000..838b291
--- /dev/null
+++ b/m4/fatal-signal.m4
@@ -0,0 +1,12 @@
+# fatal-signal.m4 serial 9
+dnl Copyright (C) 2003-2004, 2006, 2008-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FATAL_SIGNAL],
+[
+  AC_REQUIRE([gt_TYPE_SIG_ATOMIC_T])
+  AC_CHECK_HEADERS_ONCE([unistd.h])
+  gl_PREREQ_SIG_HANDLER_H
+])
diff --git a/m4/fchdir.m4 b/m4/fchdir.m4
new file mode 100644
index 0000000..8e894e0
--- /dev/null
+++ b/m4/fchdir.m4
@@ -0,0 +1,68 @@
+# fchdir.m4 serial 26
+dnl Copyright (C) 2006-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_FCHDIR],
+[
+  AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
+  AC_REQUIRE([gl_DIRENT_H_DEFAULTS])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+
+  AC_CHECK_DECLS_ONCE([fchdir])
+  if test $ac_cv_have_decl_fchdir = no; then
+    HAVE_DECL_FCHDIR=0
+  fi
+
+  AC_REQUIRE([gl_TEST_FCHDIR])
+  if test $HAVE_FCHDIR = 0; then
+    AC_LIBOBJ([fchdir])
+    gl_PREREQ_FCHDIR
+    AC_DEFINE([REPLACE_FCHDIR], [1],
+      [Define to 1 if gnulib's fchdir() replacement is used.])
+    dnl We must also replace anything that can manipulate a directory fd,
+    dnl to keep our bookkeeping up-to-date.  We don't have to replace
+    dnl fstatat, since no platform has fstatat but lacks fchdir.
+    AC_CACHE_CHECK([whether open can visit directories],
+      [gl_cv_func_open_directory_works],
+      [AC_RUN_IFELSE(
+         [AC_LANG_PROGRAM(
+            [[#include <fcntl.h>
+            ]GL_MDA_DEFINES],
+            [[return open(".", O_RDONLY) < 0;]])],
+         [gl_cv_func_open_directory_works=yes],
+         [gl_cv_func_open_directory_works=no],
+         [case "$host_os" in
+                             # Guess yes on Linux systems.
+            linux-* | linux) gl_cv_func_open_directory_works="guessing yes" ;;
+                             # Guess yes on glibc systems.
+            *-gnu* | gnu*)   gl_cv_func_open_directory_works="guessing yes" ;;
+                             # Guess no on native Windows.
+            mingw*)          gl_cv_func_open_directory_works="guessing no" ;;
+                             # If we don't know, obey --enable-cross-guesses.
+            *)               gl_cv_func_open_directory_works="$gl_cross_guess_normal" ;;
+          esac
+         ])])
+    case "$gl_cv_func_open_directory_works" in
+      *yes) ;;
+      *)
+        AC_DEFINE([REPLACE_OPEN_DIRECTORY], [1], [Define to 1 if open() should
+work around the inability to open a directory.])
+        ;;
+    esac
+  fi
+])
+
+# Determine whether to use the overrides in lib/fchdir.c.
+AC_DEFUN([gl_TEST_FCHDIR],
+[
+  AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
+  AC_CHECK_FUNCS_ONCE([fchdir])
+  if test $ac_cv_func_fchdir = no; then
+    HAVE_FCHDIR=0
+  fi
+])
+
+# Prerequisites of lib/fchdir.c.
+AC_DEFUN([gl_PREREQ_FCHDIR], [:])
diff --git a/m4/fcntl-o.m4 b/m4/fcntl-o.m4
new file mode 100644
index 0000000..3ef061d
--- /dev/null
+++ b/m4/fcntl-o.m4
@@ -0,0 +1,140 @@
+# fcntl-o.m4 serial 7
+dnl Copyright (C) 2006, 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl Written by Paul Eggert.
+
+AC_PREREQ([2.60])
+
+# Test whether the flags O_NOATIME and O_NOFOLLOW actually work.
+# Define HAVE_WORKING_O_NOATIME to 1 if O_NOATIME works, or to 0 otherwise.
+# Define HAVE_WORKING_O_NOFOLLOW to 1 if O_NOFOLLOW works, or to 0 otherwise.
+AC_DEFUN([gl_FCNTL_O_FLAGS],
+[
+  dnl Persuade glibc <fcntl.h> to define O_NOATIME and O_NOFOLLOW.
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
+
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_CHECK_HEADERS_ONCE([unistd.h])
+  AC_CHECK_FUNCS_ONCE([symlink])
+  AC_CACHE_CHECK([for working fcntl.h], [gl_cv_header_working_fcntl_h],
+    [AC_RUN_IFELSE(
+       [AC_LANG_PROGRAM(
+          [[#include <sys/types.h>
+           #include <sys/stat.h>
+           #if HAVE_UNISTD_H
+           # include <unistd.h>
+           #else /* on Windows with MSVC */
+           # include <io.h>
+           # include <stdlib.h>
+           # defined sleep(n) _sleep ((n) * 1000)
+           #endif
+           #include <fcntl.h>
+           ]GL_MDA_DEFINES[
+           #ifndef O_NOATIME
+            #define O_NOATIME 0
+           #endif
+           #ifndef O_NOFOLLOW
+            #define O_NOFOLLOW 0
+           #endif
+           static int const constants[] =
+            {
+              O_CREAT, O_EXCL, O_NOCTTY, O_TRUNC, O_APPEND,
+              O_NONBLOCK, O_SYNC, O_ACCMODE, O_RDONLY, O_RDWR, O_WRONLY
+            };
+          ]],
+          [[
+            int result = !constants;
+            #if HAVE_SYMLINK
+            {
+              static char const sym[] = "conftest.sym";
+              if (symlink ("/dev/null", sym) != 0)
+                result |= 2;
+              else
+                {
+                  int fd = open (sym, O_WRONLY | O_NOFOLLOW | O_CREAT, 0);
+                  if (fd >= 0)
+                    {
+                      close (fd);
+                      result |= 4;
+                    }
+                }
+              if (unlink (sym) != 0 || symlink (".", sym) != 0)
+                result |= 2;
+              else
+                {
+                  int fd = open (sym, O_RDONLY | O_NOFOLLOW);
+                  if (fd >= 0)
+                    {
+                      close (fd);
+                      result |= 4;
+                    }
+                }
+              unlink (sym);
+            }
+            #endif
+            {
+              static char const file[] = "confdefs.h";
+              int fd = open (file, O_RDONLY | O_NOATIME);
+              if (fd < 0)
+                result |= 8;
+              else
+                {
+                  struct stat st0;
+                  if (fstat (fd, &st0) != 0)
+                    result |= 16;
+                  else
+                    {
+                      char c;
+                      sleep (1);
+                      if (read (fd, &c, 1) != 1)
+                        result |= 24;
+                      else
+                        {
+                          if (close (fd) != 0)
+                            result |= 32;
+                          else
+                            {
+                              struct stat st1;
+                              if (stat (file, &st1) != 0)
+                                result |= 40;
+                              else
+                                if (st0.st_atime != st1.st_atime)
+                                  result |= 64;
+                            }
+                        }
+                    }
+                }
+            }
+            return result;]])],
+       [gl_cv_header_working_fcntl_h=yes],
+       [case $? in #(
+        4) gl_cv_header_working_fcntl_h='no (bad O_NOFOLLOW)';; #(
+        64) gl_cv_header_working_fcntl_h='no (bad O_NOATIME)';; #(
+        68) gl_cv_header_working_fcntl_h='no (bad O_NOATIME, O_NOFOLLOW)';; #(
+         *) gl_cv_header_working_fcntl_h='no';;
+        esac],
+       [case "$host_os" in
+                  # Guess 'no' on native Windows.
+          mingw*) gl_cv_header_working_fcntl_h='no' ;;
+          *)      gl_cv_header_working_fcntl_h=cross-compiling ;;
+        esac
+       ])
+    ])
+
+  case $gl_cv_header_working_fcntl_h in #(
+  *O_NOATIME* | no | cross-compiling) ac_val=0;; #(
+  *) ac_val=1;;
+  esac
+  AC_DEFINE_UNQUOTED([HAVE_WORKING_O_NOATIME], [$ac_val],
+    [Define to 1 if O_NOATIME works.])
+
+  case $gl_cv_header_working_fcntl_h in #(
+  *O_NOFOLLOW* | no | cross-compiling) ac_val=0;; #(
+  *) ac_val=1;;
+  esac
+  AC_DEFINE_UNQUOTED([HAVE_WORKING_O_NOFOLLOW], [$ac_val],
+    [Define to 1 if O_NOFOLLOW works.])
+])
diff --git a/m4/fcntl.m4 b/m4/fcntl.m4
new file mode 100644
index 0000000..547ff40
--- /dev/null
+++ b/m4/fcntl.m4
@@ -0,0 +1,151 @@
+# fcntl.m4 serial 11
+dnl Copyright (C) 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+# For now, this module ensures that fcntl()
+# - supports F_DUPFD correctly
+# - supports or emulates F_DUPFD_CLOEXEC
+# - supports F_GETFD
+# Still to be ported to mingw:
+# - F_SETFD
+# - F_GETFL, F_SETFL
+# - F_GETOWN, F_SETOWN
+# - F_GETLK, F_SETLK, F_SETLKW
+AC_DEFUN([gl_FUNC_FCNTL],
+[
+  dnl Persuade glibc to expose F_DUPFD_CLOEXEC.
+  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+  AC_REQUIRE([gl_FCNTL_H_DEFAULTS])
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  AC_CHECK_FUNCS_ONCE([fcntl])
+  if test $ac_cv_func_fcntl = no; then
+    gl_REPLACE_FCNTL
+  else
+    dnl cygwin 1.5.x F_DUPFD has wrong errno, and allows negative target
+    dnl haiku alpha 2 F_DUPFD has wrong errno
+    AC_CACHE_CHECK([whether fcntl handles F_DUPFD correctly],
+      [gl_cv_func_fcntl_f_dupfd_works],
+      [AC_RUN_IFELSE(
+         [AC_LANG_PROGRAM(
+            [[#include <errno.h>
+              #include <fcntl.h>
+              #include <limits.h>
+              #include <sys/resource.h>
+              #include <unistd.h>
+              ]GL_MDA_DEFINES[
+              #ifndef RLIM_SAVED_CUR
+              # define RLIM_SAVED_CUR RLIM_INFINITY
+              #endif
+              #ifndef RLIM_SAVED_MAX
+              # define RLIM_SAVED_MAX RLIM_INFINITY
+              #endif
+            ]],
+            [[int result = 0;
+              int bad_fd = INT_MAX;
+              struct rlimit rlim;
+              if (getrlimit (RLIMIT_NOFILE, &rlim) == 0
+                  && 0 <= rlim.rlim_cur && rlim.rlim_cur <= INT_MAX
+                  && rlim.rlim_cur != RLIM_INFINITY
+                  && rlim.rlim_cur != RLIM_SAVED_MAX
+                  && rlim.rlim_cur != RLIM_SAVED_CUR)
+                bad_fd = rlim.rlim_cur;
+              if (fcntl (0, F_DUPFD, -1) != -1) result |= 1;
+              if (errno != EINVAL) result |= 2;
+              if (fcntl (0, F_DUPFD, bad_fd) != -1) result |= 4;
+              if (errno != EINVAL) result |= 8;
+              /* On OS/2 kLIBC, F_DUPFD does not work on a directory fd */
+              {
+                int fd;
+                fd = open (".", O_RDONLY);
+                if (fd == -1)
+                  result |= 16;
+                else if (fcntl (fd, F_DUPFD, STDERR_FILENO + 1) == -1)
+                  result |= 32;
+
+                close (fd);
+              }
+              return result;]])],
+         [gl_cv_func_fcntl_f_dupfd_works=yes],
+         [gl_cv_func_fcntl_f_dupfd_works=no],
+         [case $host_os in
+            aix* | cygwin* | haiku*)
+               gl_cv_func_fcntl_f_dupfd_works="guessing no" ;;
+            *) gl_cv_func_fcntl_f_dupfd_works="guessing yes" ;;
+          esac])])
+    case $gl_cv_func_fcntl_f_dupfd_works in
+      *yes) ;;
+      *) gl_REPLACE_FCNTL
+        AC_DEFINE([FCNTL_DUPFD_BUGGY], [1], [Define this to 1 if F_DUPFD
+          behavior does not match POSIX]) ;;
+    esac
+
+    dnl Many systems lack F_DUPFD_CLOEXEC.
+    dnl NetBSD 9.0 declares F_DUPFD_CLOEXEC but it works only like F_DUPFD.
+    AC_CACHE_CHECK([whether fcntl understands F_DUPFD_CLOEXEC],
+      [gl_cv_func_fcntl_f_dupfd_cloexec],
+      [AC_RUN_IFELSE(
+         [AC_LANG_SOURCE(
+            [[#include <fcntl.h>
+              #include <unistd.h>
+              int main (int argc, char *argv[])
+              {
+                if (argc == 1)
+                  /* parent process */
+                  {
+                    if (fcntl (1, F_DUPFD_CLOEXEC, 10) < 0)
+                      return 1;
+                    return execl ("./conftest", "./conftest", "child", NULL);
+                  }
+                else
+                  /* child process */
+                  return (fcntl (10, F_GETFL) < 0 ? 0 : 42);
+              }
+            ]])
+         ],
+         [AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
+#ifdef __linux__
+/* The Linux kernel only added F_DUPFD_CLOEXEC in 2.6.24, so we always replace
+   it to support the semantics on older kernels that failed with EINVAL.  */
+choke me
+#endif
+           ]])],
+           [gl_cv_func_fcntl_f_dupfd_cloexec=yes],
+           [gl_cv_func_fcntl_f_dupfd_cloexec="needs runtime check"])
+         ],
+         [gl_cv_func_fcntl_f_dupfd_cloexec=no],
+         [case "$host_os" in
+                     # Guess no on NetBSD.
+            netbsd*) gl_cv_func_fcntl_f_dupfd_cloexec="guessing no" ;;
+            *)       gl_cv_func_fcntl_f_dupfd_cloexec="$gl_cross_guess_normal" ;;
+          esac
+         ])
+      ])
+    case "$gl_cv_func_fcntl_f_dupfd_cloexec" in
+      *yes) ;;
+      *)    gl_REPLACE_FCNTL
+            dnl No witness macro needed for this bug.
+            ;;
+    esac
+  fi
+  dnl Replace fcntl() for supporting the gnulib-defined fchdir() function,
+  dnl to keep fchdir's bookkeeping up-to-date.
+  m4_ifdef([gl_FUNC_FCHDIR], [
+    gl_TEST_FCHDIR
+    if test $HAVE_FCHDIR = 0; then
+      gl_REPLACE_FCNTL
+    fi
+  ])
+])
+
+AC_DEFUN([gl_REPLACE_FCNTL],
+[
+  AC_REQUIRE([gl_FCNTL_H_DEFAULTS])
+  AC_CHECK_FUNCS_ONCE([fcntl])
+  if test $ac_cv_func_fcntl = no; then
+    HAVE_FCNTL=0
+  else
+    REPLACE_FCNTL=1
+  fi
+])
diff --git a/m4/fcntl_h.m4 b/m4/fcntl_h.m4
new file mode 100644
index 0000000..c475357
--- /dev/null
+++ b/m4/fcntl_h.m4
@@ -0,0 +1,55 @@
+# serial 17
+# Configure fcntl.h.
+dnl Copyright (C) 2006-2007, 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl Written by Paul Eggert.
+
+AC_DEFUN([gl_FCNTL_H],
+[
+  AC_REQUIRE([gl_FCNTL_H_DEFAULTS])
+  AC_REQUIRE([gl_FCNTL_O_FLAGS])
+  gl_NEXT_HEADERS([fcntl.h])
+
+  dnl Ensure the type pid_t gets defined.
+  AC_REQUIRE([AC_TYPE_PID_T])
+
+  dnl Ensure the type mode_t gets defined.
+  AC_REQUIRE([AC_TYPE_MODE_T])
+
+  dnl Check for declarations of anything we want to poison if the
+  dnl corresponding gnulib module is not in use, if it is not common
+  dnl enough to be declared everywhere.
+  gl_WARN_ON_USE_PREPARE([[#include <fcntl.h>
+    ]], [fcntl openat])
+])
+
+AC_DEFUN([gl_FCNTL_MODULE_INDICATOR],
+[
+  dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
+  AC_REQUIRE([gl_FCNTL_H_DEFAULTS])
+  gl_MODULE_INDICATOR_SET_VARIABLE([$1])
+  dnl Define it also as a C macro, for the benefit of the unit tests.
+  gl_MODULE_INDICATOR_FOR_TESTS([$1])
+])
+
+AC_DEFUN([gl_FCNTL_H_DEFAULTS],
+[
+  GNULIB_CREAT=0;        AC_SUBST([GNULIB_CREAT])
+  GNULIB_FCNTL=0;        AC_SUBST([GNULIB_FCNTL])
+  GNULIB_NONBLOCKING=0;  AC_SUBST([GNULIB_NONBLOCKING])
+  GNULIB_OPEN=0;         AC_SUBST([GNULIB_OPEN])
+  GNULIB_OPENAT=0;       AC_SUBST([GNULIB_OPENAT])
+  dnl Support Microsoft deprecated alias function names by default.
+  GNULIB_MDA_CREAT=1;    AC_SUBST([GNULIB_MDA_CREAT])
+  GNULIB_MDA_OPEN=1;     AC_SUBST([GNULIB_MDA_OPEN])
+  dnl Assume proper GNU behavior unless another module says otherwise.
+  HAVE_FCNTL=1;          AC_SUBST([HAVE_FCNTL])
+  HAVE_OPENAT=1;         AC_SUBST([HAVE_OPENAT])
+  REPLACE_CREAT=0;       AC_SUBST([REPLACE_CREAT])
+  REPLACE_FCNTL=0;       AC_SUBST([REPLACE_FCNTL])
+  REPLACE_OPEN=0;        AC_SUBST([REPLACE_OPEN])
+  REPLACE_OPENAT=0;      AC_SUBST([REPLACE_OPENAT])
+])
diff --git a/m4/fdopendir.m4 b/m4/fdopendir.m4
new file mode 100644
index 0000000..9937a74
--- /dev/null
+++ b/m4/fdopendir.m4
@@ -0,0 +1,67 @@
+# serial 14
+# See if we need to provide fdopendir.
+
+dnl Copyright (C) 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+# Written by Eric Blake.
+
+AC_DEFUN([gl_FUNC_FDOPENDIR],
+[
+  AC_REQUIRE([gl_DIRENT_H_DEFAULTS])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+
+  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+
+  dnl FreeBSD 7.3 has the function, but failed to declare it.
+  AC_CHECK_DECLS([fdopendir], [], [HAVE_DECL_FDOPENDIR=0], [[
+#include <dirent.h>
+    ]])
+  AC_CHECK_FUNCS_ONCE([fdopendir])
+  if test $ac_cv_func_fdopendir = no; then
+    HAVE_FDOPENDIR=0
+  else
+    AC_CACHE_CHECK([whether fdopendir works],
+      [gl_cv_func_fdopendir_works],
+      [AC_RUN_IFELSE(
+         [AC_LANG_PROGRAM([[
+#include <dirent.h>
+#include <fcntl.h>
+#include <unistd.h>
+]GL_MDA_DEFINES[
+#if !HAVE_DECL_FDOPENDIR
+extern
+# ifdef __cplusplus
+"C"
+# endif
+DIR *fdopendir (int);
+#endif
+]],
+            [[int result = 0;
+              int fd = open ("conftest.c", O_RDONLY);
+              if (fd < 0) result |= 1;
+              if (fdopendir (fd)) result |= 2;
+              if (close (fd)) result |= 4;
+              return result;
+            ]])],
+         [gl_cv_func_fdopendir_works=yes],
+         [gl_cv_func_fdopendir_works=no],
+         [case "$host_os" in
+                     # Guess yes on glibc systems.
+            *-gnu*)  gl_cv_func_fdopendir_works="guessing yes" ;;
+                     # Guess yes on musl systems.
+            *-musl*) gl_cv_func_fdopendir_works="guessing yes" ;;
+                     # If we don't know, obey --enable-cross-guesses.
+            *)       gl_cv_func_fdopendir_works="$gl_cross_guess_normal" ;;
+          esac
+         ])])
+    case "$gl_cv_func_fdopendir_works" in
+      *yes) ;;
+      *)
+        REPLACE_FDOPENDIR=1
+        ;;
+    esac
+  fi
+])
diff --git a/m4/fflush.m4 b/m4/fflush.m4
new file mode 100644
index 0000000..8f63c25
--- /dev/null
+++ b/m4/fflush.m4
@@ -0,0 +1,100 @@
+# fflush.m4 serial 18
+
+# Copyright (C) 2007-2020 Free Software Foundation, Inc.
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+dnl From Eric Blake
+
+dnl Find out how to obey POSIX semantics of fflush(stdin) discarding
+dnl unread input on seekable streams, rather than C99 undefined semantics.
+
+AC_DEFUN([gl_FUNC_FFLUSH],
+[
+  AC_REQUIRE([gl_STDIO_H_DEFAULTS])
+  gl_FUNC_FFLUSH_STDIN
+  case "$gl_cv_func_fflush_stdin" in
+    *yes) ;;
+    *) REPLACE_FFLUSH=1 ;;
+  esac
+])
+
+dnl Determine whether fflush works on input streams.
+dnl Sets gl_cv_func_fflush_stdin.
+
+AC_DEFUN([gl_FUNC_FFLUSH_STDIN],
+[
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_CHECK_HEADERS_ONCE([unistd.h])
+  AC_CACHE_CHECK([whether fflush works on input streams],
+    [gl_cv_func_fflush_stdin],
+    [echo hello world > conftest.txt
+     AC_RUN_IFELSE([AC_LANG_PROGRAM(
+       [[
+#include <stdio.h>
+#if HAVE_UNISTD_H
+# include <unistd.h>
+#else /* on Windows with MSVC */
+# include <io.h>
+#endif
+       ]GL_MDA_DEFINES],
+       [[FILE *f = fopen ("conftest.txt", "r");
+         char buffer[10];
+         int fd;
+         int c;
+         if (f == NULL)
+           return 1;
+         fd = fileno (f);
+         if (fd < 0 || fread (buffer, 1, 5, f) != 5)
+           { fclose (f); return 2; }
+         /* For deterministic results, ensure f read a bigger buffer.  */
+         if (lseek (fd, 0, SEEK_CUR) == 5)
+           { fclose (f); return 3; }
+         /* POSIX requires fflush-fseek to set file offset of fd.  This fails
+            on BSD systems and on mingw.  */
+         if (fflush (f) != 0 || fseek (f, 0, SEEK_CUR) != 0)
+           { fclose (f); return 4; }
+         if (lseek (fd, 0, SEEK_CUR) != 5)
+           { fclose (f); return 5; }
+         /* Verify behaviour of fflush after ungetc. See
+            <https://www.opengroup.org/austin/aardvark/latest/xshbug3.txt>  */
+         /* Verify behaviour of fflush after a backup ungetc.  This fails on
+            mingw.  */
+         c = fgetc (f);
+         ungetc (c, f);
+         fflush (f);
+         if (fgetc (f) != c)
+           { fclose (f); return 6; }
+         /* Verify behaviour of fflush after a non-backup ungetc.  This fails
+            on glibc 2.8 and on BSD systems.  */
+         c = fgetc (f);
+         ungetc ('@', f);
+         fflush (f);
+         if (fgetc (f) != c)
+           { fclose (f); return 7; }
+         fclose (f);
+         return 0;
+       ]])],
+       [gl_cv_func_fflush_stdin=yes],
+       [gl_cv_func_fflush_stdin=no],
+       [case "$host_os" in
+                  # Guess no on native Windows.
+          mingw*) gl_cv_func_fflush_stdin="guessing no" ;;
+          *)      gl_cv_func_fflush_stdin=cross ;;
+        esac
+       ])
+     rm conftest.txt
+    ])
+  case "$gl_cv_func_fflush_stdin" in
+    *yes) gl_func_fflush_stdin=1 ;;
+    *no)  gl_func_fflush_stdin=0 ;;
+    *)    gl_func_fflush_stdin='(-1)' ;;
+  esac
+  AC_DEFINE_UNQUOTED([FUNC_FFLUSH_STDIN], [$gl_func_fflush_stdin],
+    [Define to 1 if fflush is known to work on stdin as per POSIX.1-2008,
+     0 if fflush is known to not work, -1 if unknown.])
+])
+
+# Prerequisites of lib/fflush.c.
+AC_DEFUN([gl_PREREQ_FFLUSH], [:])
diff --git a/m4/filenamecat.m4 b/m4/filenamecat.m4
new file mode 100644
index 0000000..7eff5b9
--- /dev/null
+++ b/m4/filenamecat.m4
@@ -0,0 +1,16 @@
+# filenamecat.m4 serial 11
+dnl Copyright (C) 2002-2006, 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FILE_NAME_CONCAT],
+[
+  AC_REQUIRE([gl_FILE_NAME_CONCAT_LGPL])
+])
+
+AC_DEFUN([gl_FILE_NAME_CONCAT_LGPL],
+[
+  dnl Prerequisites of lib/filenamecat-lgpl.c.
+  AC_CHECK_FUNCS_ONCE([mempcpy])
+])
diff --git a/m4/findprog-in.m4 b/m4/findprog-in.m4
new file mode 100644
index 0000000..54ea10e
--- /dev/null
+++ b/m4/findprog-in.m4
@@ -0,0 +1,11 @@
+# findprog-in.m4 serial 1
+dnl Copyright (C) 2003, 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FINDPROG_IN],
+[
+  dnl Prerequisites of lib/findprog-in.c.
+  AC_REQUIRE([gl_FUNC_EACCESS])
+])
diff --git a/m4/flexmember.m4 b/m4/flexmember.m4
new file mode 100644
index 0000000..90f3ddd
--- /dev/null
+++ b/m4/flexmember.m4
@@ -0,0 +1,44 @@
+# serial 5
+# Check for flexible array member support.
+
+# Copyright (C) 2006, 2009-2020 Free Software Foundation, Inc.
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+# Written by Paul Eggert.
+
+AC_DEFUN([AC_C_FLEXIBLE_ARRAY_MEMBER],
+[
+  AC_CACHE_CHECK([for flexible array member],
+    ac_cv_c_flexmember,
+    [AC_COMPILE_IFELSE(
+       [AC_LANG_PROGRAM(
+          [[#include <stdlib.h>
+            #include <stdio.h>
+            #include <stddef.h>
+            struct m { struct m *next, **list; char name[]; };
+            struct s { struct s *p; struct m *m; int n; double d[]; };]],
+          [[int m = getchar ();
+            size_t nbytes = offsetof (struct s, d) + m * sizeof (double);
+            nbytes += sizeof (struct s) - 1;
+            nbytes -= nbytes % sizeof (struct s);
+            struct s *p = malloc (nbytes);
+            p->p = p;
+            p->m = NULL;
+            p->d[0] = 0.0;
+            return p->d != (double *) NULL;]])],
+       [ac_cv_c_flexmember=yes],
+       [ac_cv_c_flexmember=no])])
+  if test $ac_cv_c_flexmember = yes; then
+    AC_DEFINE([FLEXIBLE_ARRAY_MEMBER], [],
+      [Define to nothing if C supports flexible array members, and to
+       1 if it does not.  That way, with a declaration like 'struct s
+       { int n; short d@<:@FLEXIBLE_ARRAY_MEMBER@:>@; };', the struct hack
+       can be used with pre-C99 compilers.
+       Use 'FLEXSIZEOF (struct s, d, N * sizeof (short))' to calculate
+       the size in bytes of such a struct containing an N-element array.])
+  else
+    AC_DEFINE([FLEXIBLE_ARRAY_MEMBER], [1])
+  fi
+])
diff --git a/m4/float_h.m4 b/m4/float_h.m4
new file mode 100644
index 0000000..3ef0bb7
--- /dev/null
+++ b/m4/float_h.m4
@@ -0,0 +1,108 @@
+# float_h.m4 serial 12
+dnl Copyright (C) 2007, 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FLOAT_H],
+[
+  AC_REQUIRE([AC_PROG_CC])
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  FLOAT_H=
+  REPLACE_FLOAT_LDBL=0
+  case "$host_os" in
+    aix* | beos* | openbsd* | mirbsd* | irix*)
+      FLOAT_H=float.h
+      ;;
+    freebsd* | dragonfly*)
+      case "$host_cpu" in
+changequote(,)dnl
+        i[34567]86 )
+changequote([,])dnl
+          FLOAT_H=float.h
+          ;;
+        x86_64 )
+          # On x86_64 systems, the C compiler may still be generating
+          # 32-bit code.
+          AC_COMPILE_IFELSE(
+            [AC_LANG_SOURCE(
+               [[#if defined __LP64__ || defined __x86_64__ || defined __amd64__
+                  int ok;
+                 #else
+                  error fail
+                 #endif
+               ]])],
+            [],
+            [FLOAT_H=float.h])
+          ;;
+      esac
+      ;;
+    linux*)
+      case "$host_cpu" in
+        powerpc*)
+          FLOAT_H=float.h
+          ;;
+      esac
+      ;;
+  esac
+  case "$host_os" in
+    aix* | freebsd* | dragonfly* | linux*)
+      if test -n "$FLOAT_H"; then
+        REPLACE_FLOAT_LDBL=1
+      fi
+      ;;
+  esac
+
+  dnl Test against glibc-2.7 Linux/SPARC64 bug.
+  REPLACE_ITOLD=0
+  AC_CACHE_CHECK([whether conversion from 'int' to 'long double' works],
+    [gl_cv_func_itold_works],
+    [
+      AC_RUN_IFELSE(
+        [AC_LANG_SOURCE([[
+int i = -1;
+volatile long double ld;
+int main ()
+{
+  ld += i * 1.0L;
+  if (ld > 0)
+    return 1;
+  return 0;
+}]])],
+        [gl_cv_func_itold_works=yes],
+        [gl_cv_func_itold_works=no],
+        [case "$host" in
+           sparc*-*-linux*)
+             AC_COMPILE_IFELSE(
+               [AC_LANG_SOURCE(
+                 [[#if defined __LP64__ || defined __arch64__
+                    int ok;
+                   #else
+                    error fail
+                   #endif
+                 ]])],
+               [gl_cv_func_itold_works="guessing no"],
+               [gl_cv_func_itold_works="guessing yes"])
+             ;;
+                   # Guess yes on native Windows.
+           mingw*) gl_cv_func_itold_works="guessing yes" ;;
+           *)      gl_cv_func_itold_works="guessing yes" ;;
+         esac
+        ])
+    ])
+  case "$gl_cv_func_itold_works" in
+    *no)
+      REPLACE_ITOLD=1
+      dnl We add the workaround to <float.h> but also to <math.h>,
+      dnl to increase the chances that the fix function gets pulled in.
+      FLOAT_H=float.h
+      ;;
+  esac
+
+  if test -n "$FLOAT_H"; then
+    gl_NEXT_HEADERS([float.h])
+  fi
+  AC_SUBST([FLOAT_H])
+  AM_CONDITIONAL([GL_GENERATE_FLOAT_H], [test -n "$FLOAT_H"])
+  AC_SUBST([REPLACE_ITOLD])
+])
diff --git a/m4/flock.m4 b/m4/flock.m4
new file mode 100644
index 0000000..bb48733
--- /dev/null
+++ b/m4/flock.m4
@@ -0,0 +1,24 @@
+# flock.m4 serial 3
+dnl Copyright (C) 2008-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_FLOCK],
+[
+  AC_REQUIRE([gl_HEADER_SYS_FILE_H_DEFAULTS])
+  AC_CHECK_FUNCS_ONCE([flock])
+  if test $ac_cv_func_flock = no; then
+    HAVE_FLOCK=0
+  fi
+])
+
+dnl Prerequisites of lib/flock.c.
+AC_DEFUN([gl_PREREQ_FLOCK],
+[
+  AC_CHECK_FUNCS_ONCE([fcntl])
+  AC_CHECK_HEADERS_ONCE([unistd.h])
+
+  dnl Do we have a POSIX fcntl lock implementation?
+  AC_CHECK_MEMBERS([struct flock.l_type],[],[],[[#include <fcntl.h>]])
+])
diff --git a/m4/fnmatch.m4 b/m4/fnmatch.m4
new file mode 100644
index 0000000..2f8e4a8
--- /dev/null
+++ b/m4/fnmatch.m4
@@ -0,0 +1,153 @@
+# Check for fnmatch - serial 15.  -*- coding: utf-8 -*-
+
+# Copyright (C) 2000-2007, 2009-2020 Free Software Foundation, Inc.
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+# Autoconf defines AC_FUNC_FNMATCH, but that is obsolescent.
+# New applications should use the macros below instead.
+
+# Request a POSIX compliant fnmatch function.
+AC_DEFUN([gl_FUNC_FNMATCH_POSIX],
+[
+  m4_divert_text([DEFAULTS], [gl_fnmatch_required=POSIX])
+
+  AC_REQUIRE([gl_FNMATCH_H])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  gl_fnmatch_required_lowercase=`
+    echo $gl_fnmatch_required | LC_ALL=C tr '[[A-Z]]' '[[a-z]]'
+  `
+  AC_CHECK_FUNCS_ONCE([fnmatch])
+  if test $ac_cv_func_fnmatch = no; then
+    HAVE_FNMATCH=0
+  else
+    gl_fnmatch_cache_var="gl_cv_func_fnmatch_${gl_fnmatch_required_lowercase}"
+    AC_CACHE_CHECK([for working $gl_fnmatch_required fnmatch],
+      [$gl_fnmatch_cache_var],
+      [dnl Some versions of Solaris, SCO, and the GNU C Library
+       dnl have a broken or incompatible fnmatch.
+       dnl So we run a test program.  If we are cross-compiling, take no chance.
+       dnl Thanks to John Oleynick, François Pinard, and Paul Eggert for this
+       dnl test.
+       if test $gl_fnmatch_required = GNU; then
+         gl_fnmatch_gnu_start=
+         gl_fnmatch_gnu_end=
+       else
+         gl_fnmatch_gnu_start='#if 0'
+         gl_fnmatch_gnu_end='#endif'
+       fi
+       AC_RUN_IFELSE(
+         [AC_LANG_PROGRAM(
+            [[#include <fnmatch.h>
+              static int
+              y (char const *pattern, char const *string, int flags)
+              {
+                return fnmatch (pattern, string, flags) == 0;
+              }
+              static int
+              n (char const *pattern, char const *string, int flags)
+              {
+                return fnmatch (pattern, string, flags) == FNM_NOMATCH;
+              }
+            ]],
+            [[char const *Apat = 'A' < '\\\\' ? "[A-\\\\\\\\]" : "[\\\\\\\\-A]";
+              char const *apat = 'a' < '\\\\' ? "[a-\\\\\\\\]" : "[\\\\\\\\-a]";
+              static char const A_1[] = { 'A' - 1, 0 };
+              static char const A01[] = { 'A' + 1, 0 };
+              static char const a_1[] = { 'a' - 1, 0 };
+              static char const a01[] = { 'a' + 1, 0 };
+              static char const bs_1[] = { '\\\\' - 1, 0 };
+              static char const bs01[] = { '\\\\' + 1, 0 };
+              int result = 0;
+              if (!n ("a*", "", 0))
+                return 1;
+              if (!y ("a*", "abc", 0))
+                return 1;
+              if (!y ("[/b", "[/b", 0)) /*"]]"*/ /* glibc Bugzilla bug 12378 */
+                return 1;
+              if (!n ("d*/*1", "d/s/1", FNM_PATHNAME))
+                return 2;
+              if (!y ("a\\\\bc", "abc", 0))
+                return 3;
+              if (!n ("a\\\\bc", "abc", FNM_NOESCAPE))
+                return 3;
+              if (!y ("*x", ".x", 0))
+                return 4;
+              if (!n ("*x", ".x", FNM_PERIOD))
+                return 4;
+              if (!y (Apat, "\\\\", 0))
+                return 5;
+              if (!y (Apat, "A", 0))
+                return 5;
+              if (!y (apat, "\\\\", 0))
+                return 5;
+              if (!y (apat, "a", 0))
+                return 5;
+              if (!(n (Apat, A_1, 0) == ('A' < '\\\\')))
+                return 5;
+              if (!(n (apat, a_1, 0) == ('a' < '\\\\')))
+                return 5;
+              if (!(y (Apat, A01, 0) == ('A' < '\\\\')))
+                return 5;
+              if (!(y (apat, a01, 0) == ('a' < '\\\\')))
+                return 5;
+              if (!(y (Apat, bs_1, 0) == ('A' < '\\\\')))
+                return 5;
+              if (!(y (apat, bs_1, 0) == ('a' < '\\\\')))
+                return 5;
+              if (!(n (Apat, bs01, 0) == ('A' < '\\\\')))
+                return 5;
+              if (!(n (apat, bs01, 0) == ('a' < '\\\\')))
+                return 5;
+              $gl_fnmatch_gnu_start
+              if (!y ("xxXX", "xXxX", FNM_CASEFOLD))
+                result |= 8;
+              if (!y ("a++(x|yy)b", "a+xyyyyxb", FNM_EXTMATCH))
+                result |= 16;
+              if (!n ("d*/*1", "d/s/1", FNM_FILE_NAME))
+                result |= 32;
+              if (!y ("*", "x", FNM_FILE_NAME | FNM_LEADING_DIR))
+                result |= 64;
+              if (!y ("x*", "x/y/z", FNM_FILE_NAME | FNM_LEADING_DIR))
+                result |= 64;
+              if (!y ("*c*", "c/x", FNM_FILE_NAME | FNM_LEADING_DIR))
+                result |= 64;
+              $gl_fnmatch_gnu_end
+              return result;
+            ]])],
+         [eval "$gl_fnmatch_cache_var=yes"],
+         [eval "$gl_fnmatch_cache_var=no"],
+         [case "$host_os" in
+                     # Guess yes on musl systems.
+            *-musl*) eval "$gl_fnmatch_cache_var=\"guessing yes\"" ;;
+                     # Guess no otherwise, even on glibc systems.
+            *)       eval "$gl_fnmatch_cache_var=\"guessing no\"" ;;
+          esac
+         ])
+      ])
+    eval "gl_fnmatch_result=\"\$$gl_fnmatch_cache_var\""
+    case "$gl_fnmatch_result" in
+      *yes) ;;
+      *) REPLACE_FNMATCH=1 ;;
+    esac
+  fi
+  if test $HAVE_FNMATCH = 0 || test $REPLACE_FNMATCH = 1; then
+    gl_REPLACE_FNMATCH_H
+  fi
+])
+
+# Request a POSIX compliant fnmatch function with GNU extensions.
+AC_DEFUN([gl_FUNC_FNMATCH_GNU],
+[
+  m4_divert_text([INIT_PREPARE], [gl_fnmatch_required=GNU])
+
+  AC_REQUIRE([gl_FUNC_FNMATCH_POSIX])
+])
+
+AC_DEFUN([gl_PREREQ_FNMATCH],
+[
+  dnl Prerequisites of lib/fnmatch.c.
+  AC_REQUIRE([AC_TYPE_MBSTATE_T])
+  AC_CHECK_FUNCS_ONCE([mbsrtowcs])
+])
diff --git a/m4/fnmatch_h.m4 b/m4/fnmatch_h.m4
new file mode 100644
index 0000000..a21ec2c
--- /dev/null
+++ b/m4/fnmatch_h.m4
@@ -0,0 +1,75 @@
+# fnmatch_h.m4 serial 4
+dnl Copyright (C) 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl From Bruno Haible.
+
+AC_DEFUN_ONCE([gl_FNMATCH_H],
+[
+  AC_REQUIRE([gl_FNMATCH_H_DEFAULTS])
+  m4_ifdef([gl_ANSI_CXX], [AC_REQUIRE([gl_ANSI_CXX])])
+  AC_CHECK_HEADERS_ONCE([fnmatch.h])
+  gl_CHECK_NEXT_HEADERS([fnmatch.h])
+
+  dnl Persuade glibc <fnmatch.h> to declare FNM_CASEFOLD etc.
+  dnl This is only needed if gl_fnmatch_required = GNU. It would be possible
+  dnl to avoid this dependency for gl_FUNC_FNMATCH_POSIX by putting
+  dnl gl_FUNC_FNMATCH_GNU into a separate .m4 file.
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
+
+  if test $ac_cv_header_fnmatch_h = yes; then
+    HAVE_FNMATCH_H=1
+  else
+    HAVE_FNMATCH_H=0
+  fi
+  AC_SUBST([HAVE_FNMATCH_H])
+
+  m4_ifdef([gl_POSIXCHECK],
+    [FNMATCH_H=fnmatch.h],
+    [FNMATCH_H=''
+     if m4_ifdef([gl_ANSI_CXX], [test "$CXX" != no], [false]); then
+       dnl Override <fnmatch.h> always, to support the C++ GNULIB_NAMESPACE.
+       FNMATCH_H=fnmatch.h
+     else
+       if test $ac_cv_header_fnmatch_h != yes; then
+         dnl Provide a substitute <fnmatch.h> file.
+         FNMATCH_H=fnmatch.h
+       fi
+     fi
+    ])
+  AC_SUBST([FNMATCH_H])
+  AM_CONDITIONAL([GL_GENERATE_FNMATCH_H], [test -n "$FNMATCH_H"])
+
+  dnl Check for declarations of anything we want to poison if the
+  dnl corresponding gnulib module is not in use.
+  gl_WARN_ON_USE_PREPARE([[#include <fnmatch.h>
+    ]],
+    [fnmatch])
+])
+
+dnl Unconditionally enables the replacement of <fnmatch.h>.
+AC_DEFUN([gl_REPLACE_FNMATCH_H],
+[
+  AC_REQUIRE([gl_FNMATCH_H_DEFAULTS])
+  FNMATCH_H='fnmatch.h'
+  AM_CONDITIONAL([GL_GENERATE_FNMATCH_H], [test -n "$FNMATCH_H"])
+])
+
+AC_DEFUN([gl_FNMATCH_MODULE_INDICATOR],
+[
+  dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
+  AC_REQUIRE([gl_FNMATCH_H_DEFAULTS])
+  gl_MODULE_INDICATOR_SET_VARIABLE([$1])
+  dnl Define it also as a C macro, for the benefit of the unit tests.
+  gl_MODULE_INDICATOR_FOR_TESTS([$1])
+])
+
+AC_DEFUN([gl_FNMATCH_H_DEFAULTS],
+[
+  GNULIB_FNMATCH=0;          AC_SUBST([GNULIB_FNMATCH])
+  dnl Assume POSIX behavior unless another module says otherwise.
+  HAVE_FNMATCH=1;            AC_SUBST([HAVE_FNMATCH])
+  REPLACE_FNMATCH=0;         AC_SUBST([REPLACE_FNMATCH])
+])
diff --git a/m4/fopen.m4 b/m4/fopen.m4
new file mode 100644
index 0000000..a5d687a
--- /dev/null
+++ b/m4/fopen.m4
@@ -0,0 +1,148 @@
+# fopen.m4 serial 12
+dnl Copyright (C) 2007-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_FOPEN],
+[
+  AC_REQUIRE([gl_STDIO_H_DEFAULTS])
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  case "$host_os" in
+    mingw* | pw*)
+      dnl Replace fopen, for handling of "/dev/null".
+      REPLACE_FOPEN=1
+      dnl fopen on mingw also has the trailing slash bug.
+      gl_cv_func_fopen_slash="guessing no"
+      ;;
+    *)
+      dnl fopen("foo/", "w") should not create a file when the file name has a
+      dnl trailing slash.
+      AC_CACHE_CHECK([whether fopen recognizes a trailing slash],
+        [gl_cv_func_fopen_slash],
+        [
+          AC_RUN_IFELSE(
+            [AC_LANG_SOURCE([[
+#include <stddef.h>
+#include <stdio.h>
+int main ()
+{
+  FILE *fp = fopen ("conftest.sl/", "w");
+  int result = (fp != NULL);
+  if (fp != NULL)
+    fclose (fp);
+  return result;
+}]])],
+            [gl_cv_func_fopen_slash=yes],
+            [gl_cv_func_fopen_slash=no],
+            [
+changequote(,)dnl
+             case "$host_os" in
+               aix* | hpux* | solaris2.[0-9] | solaris2.[0-9].*)
+                 gl_cv_func_fopen_slash="guessing no" ;;
+               *)
+                 gl_cv_func_fopen_slash="guessing yes" ;;
+             esac
+changequote([,])dnl
+            ])
+          rm -f conftest.sl
+        ])
+      ;;
+  esac
+  case "$gl_cv_func_fopen_slash" in
+    *no)
+      AC_DEFINE([FOPEN_TRAILING_SLASH_BUG], [1],
+        [Define to 1 if fopen() fails to recognize a trailing slash.])
+      REPLACE_FOPEN=1
+      ;;
+  esac
+])
+
+AC_DEFUN([gl_FUNC_FOPEN_GNU],
+[
+  AC_REQUIRE([gl_FUNC_FOPEN])
+  AC_CACHE_CHECK([whether fopen supports the mode character 'x'],
+    [gl_cv_func_fopen_mode_x],
+    [rm -f conftest.x
+     AC_RUN_IFELSE(
+       [AC_LANG_SOURCE([[
+#include <stdio.h>
+#include <errno.h>
+int main ()
+{
+  FILE *fp;
+  fp = fopen ("conftest.x", "w");
+  fclose (fp);
+  fp = fopen ("conftest.x", "wx");
+  if (fp != NULL)
+    /* 'x' ignored */
+    return 1;
+  else if (errno == EEXIST)
+    return 0;
+  else
+    /* 'x' rejected */
+    return 2;
+}]])],
+       [gl_cv_func_fopen_mode_x=yes],
+       [gl_cv_func_fopen_mode_x=no],
+       [case "$host_os" in
+          # Guess yes on glibc and musl systems.
+          linux*-gnu* | gnu* | kfreebsd*-gnu | *-musl*)
+            gl_cv_func_fopen_mode_x="guessing yes" ;;
+          # If we don't know, obey --enable-cross-guesses.
+          *)
+            gl_cv_func_fopen_mode_x="$gl_cross_guess_normal" ;;
+        esac
+       ])
+     rm -f conftest.x
+    ])
+  AC_CACHE_CHECK([whether fopen supports the mode character 'e'],
+    [gl_cv_func_fopen_mode_e],
+    [echo foo > conftest.x
+     AC_RUN_IFELSE(
+       [AC_LANG_SOURCE([[
+#include <stdio.h>
+#include <errno.h>
+#include <fcntl.h>
+]GL_MDA_DEFINES[
+int main ()
+{
+  FILE *fp = fopen ("conftest.x", "re");
+  if (fp != NULL)
+    {
+      if (fcntl (fileno (fp), F_GETFD) & FD_CLOEXEC)
+        return 0;
+      else
+        /* 'e' ignored */
+        return 1;
+    }
+  else
+    /* 'e' rejected */
+    return 2;
+}]])],
+       [gl_cv_func_fopen_mode_e=yes],
+       [gl_cv_func_fopen_mode_e=no],
+       [case "$host_os" in
+          # Guess yes on glibc and musl systems.
+          linux*-gnu* | gnu* | kfreebsd*-gnu | *-musl*)
+            gl_cv_func_fopen_mode_e="guessing yes" ;;
+          # Guess no on native Windows.
+          mingw*)
+            gl_cv_func_fopen_mode_e="guessing no" ;;
+          # If we don't know, obey --enable-cross-guesses.
+          *)
+            gl_cv_func_fopen_mode_e="$gl_cross_guess_normal" ;;
+        esac
+       ])
+     rm -f conftest.x
+    ])
+  case "$gl_cv_func_fopen_mode_x" in
+    *no) REPLACE_FOPEN=1 ;;
+  esac
+  case "$gl_cv_func_fopen_mode_e" in
+    *no) REPLACE_FOPEN=1 ;;
+  esac
+])
+
+# Prerequisites of lib/fopen.c.
+AC_DEFUN([gl_PREREQ_FOPEN], [:])
diff --git a/m4/fpurge.m4 b/m4/fpurge.m4
new file mode 100644
index 0000000..9a486e0
--- /dev/null
+++ b/m4/fpurge.m4
@@ -0,0 +1,73 @@
+# fpurge.m4 serial 12
+dnl Copyright (C) 2007, 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_FPURGE],
+[
+  AC_REQUIRE([gl_STDIO_H_DEFAULTS])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_CHECK_HEADERS_ONCE([stdio_ext.h])
+  AC_CHECK_FUNCS_ONCE([fpurge])
+  AC_CHECK_FUNCS_ONCE([__fpurge])
+  AC_CHECK_DECLS([fpurge], , , [[#include <stdio.h>]])
+  if test "x$ac_cv_func_fpurge" = xyes; then
+    HAVE_FPURGE=1
+    # Detect BSD bug.  Only cygwin 1.7 and musl are known to be immune.
+    AC_CACHE_CHECK([whether fpurge works], [gl_cv_func_fpurge_works],
+      [AC_RUN_IFELSE(
+         [AC_LANG_PROGRAM(
+            [[#include <stdio.h>
+]],
+            [[FILE *f = fopen ("conftest.txt", "w+");
+              if (!f)
+                return 1;
+              if (fputc ('a', f) != 'a')
+                { fclose (f); return 2; }
+              rewind (f);
+              if (fgetc (f) != 'a')
+                { fclose (f); return 3; }
+              if (fgetc (f) != EOF)
+                { fclose (f); return 4; }
+              if (fpurge (f) != 0)
+                { fclose (f); return 5; }
+              if (putc ('b', f) != 'b')
+                { fclose (f); return 6; }
+              if (fclose (f) != 0)
+                return 7;
+              if ((f = fopen ("conftest.txt", "r")) == NULL)
+                return 8;
+              if (fgetc (f) != 'a')
+                { fclose (f); return 9; }
+              if (fgetc (f) != 'b')
+                { fclose (f); return 10; }
+              if (fgetc (f) != EOF)
+                { fclose (f); return 11; }
+              if (fclose (f) != 0)
+                return 12;
+              if (remove ("conftest.txt") != 0)
+                return 13;
+              return 0;
+            ]])],
+         [gl_cv_func_fpurge_works=yes],
+         [gl_cv_func_fpurge_works=no],
+         [case "$host_os" in
+                     # Guess yes on musl systems.
+            *-musl*) gl_cv_func_fpurge_works="guessing yes" ;;
+                     # Otherwise obey --enable-cross-guesses.
+            *)       gl_cv_func_fpurge_works="$gl_cross_guess_normal" ;;
+          esac
+         ])
+      ])
+    case "$gl_cv_func_fpurge_works" in
+      *yes) ;;
+      *) REPLACE_FPURGE=1 ;;
+    esac
+  else
+    HAVE_FPURGE=0
+  fi
+  if test "x$ac_cv_have_decl_fpurge" = xno; then
+    HAVE_DECL_FPURGE=0
+  fi
+])
diff --git a/m4/freading.m4 b/m4/freading.m4
new file mode 100644
index 0000000..6eb25ab
--- /dev/null
+++ b/m4/freading.m4
@@ -0,0 +1,11 @@
+# freading.m4 serial 2
+dnl Copyright (C) 2007, 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_FREADING],
+[
+  AC_CHECK_HEADERS_ONCE([stdio_ext.h])
+  AC_CHECK_FUNCS_ONCE([__freading])
+])
diff --git a/m4/free.m4 b/m4/free.m4
new file mode 100644
index 0000000..bf9fc31
--- /dev/null
+++ b/m4/free.m4
@@ -0,0 +1,49 @@
+# free.m4 serial 5
+# Copyright (C) 2003-2005, 2009-2020 Free Software Foundation, Inc.
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+# Written by Paul Eggert and Bruno Haible.
+
+AC_DEFUN([gl_FUNC_FREE],
+[
+  AC_REQUIRE([gl_STDLIB_H_DEFAULTS])
+
+  dnl In the next release of POSIX, free must preserve errno.
+  dnl https://www.austingroupbugs.net/view.php?id=385
+  dnl https://sourceware.org/bugzilla/show_bug.cgi?id=17924
+  dnl So far, we know of three platforms that do this:
+  dnl * glibc >= 2.33, thanks to the fix for this bug:
+  dnl   <https://sourceware.org/bugzilla/show_bug.cgi?id=17924>
+  dnl * OpenBSD >= 4.5, thanks to this commit:
+  dnl   <https://cvsweb.openbsd.org/cgi-bin/cvsweb/src/lib/libc/stdlib/malloc.c.diff?r1=1.100&r2=1.101&f=h>
+  dnl * Solaris, because its malloc() implementation is based on brk(),
+  dnl   not mmap(); hence its free() implementation makes no system calls.
+  dnl For other platforms, you can only be sure if they state it in their
+  dnl documentation, or by code inspection of the free() implementation in libc.
+  AC_CACHE_CHECK([whether free is known to preserve errno],
+    [gl_cv_func_free_preserves_errno],
+    [AC_COMPILE_IFELSE(
+       [AC_LANG_PROGRAM(
+          [[#include <stdlib.h>
+          ]],
+          [[#if 2 < __GLIBC__ + (33 <= __GLIBC_MINOR__)
+            #elif defined __OpenBSD__
+            #elif defined __sun
+            #else
+              #error "'free' is not known to preserve errno"
+            #endif
+          ]])],
+       [gl_cv_func_free_preserves_errno=yes],
+       [gl_cv_func_free_preserves_errno=no])
+    ])
+
+  case $gl_cv_func_free_preserves_errno in
+   *yes) ;;
+   *) REPLACE_FREE=1 ;;
+  esac
+])
+
+# Prerequisites of lib/free.c.
+AC_DEFUN([gl_PREREQ_FREE], [:])
diff --git a/m4/fseek.m4 b/m4/fseek.m4
new file mode 100644
index 0000000..e36508c
--- /dev/null
+++ b/m4/fseek.m4
@@ -0,0 +1,15 @@
+# fseek.m4 serial 4
+dnl Copyright (C) 2007, 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_FSEEK],
+[
+  AC_REQUIRE([gl_STDIO_H_DEFAULTS])
+  AC_REQUIRE([gl_FUNC_FSEEKO])
+  dnl When fseeko needs fixes, fseek needs them too.
+  if test $HAVE_FSEEKO = 0 || test $REPLACE_FSEEKO = 1; then
+    REPLACE_FSEEK=1
+  fi
+])
diff --git a/m4/fseeko.m4 b/m4/fseeko.m4
new file mode 100644
index 0000000..a64e640
--- /dev/null
+++ b/m4/fseeko.m4
@@ -0,0 +1,77 @@
+# fseeko.m4 serial 20
+dnl Copyright (C) 2007-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_FSEEKO],
+[
+  AC_REQUIRE([gl_STDIO_H_DEFAULTS])
+  AC_REQUIRE([gl_STDIN_LARGE_OFFSET])
+  AC_REQUIRE([gl_SYS_TYPES_H])
+  AC_REQUIRE([AC_PROG_CC])
+
+  dnl Persuade glibc <stdio.h> to declare fseeko().
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
+
+  AC_CACHE_CHECK([for fseeko], [gl_cv_func_fseeko],
+    [
+      AC_LINK_IFELSE([AC_LANG_PROGRAM([[#include <stdio.h>
+]], [[fseeko (stdin, 0, 0);]])],
+        [gl_cv_func_fseeko=yes], [gl_cv_func_fseeko=no])
+    ])
+
+  AC_CHECK_DECLS_ONCE([fseeko])
+  if test $ac_cv_have_decl_fseeko = no; then
+    HAVE_DECL_FSEEKO=0
+  fi
+
+  if test $gl_cv_func_fseeko = no; then
+    HAVE_FSEEKO=0
+  else
+    if test $WINDOWS_64_BIT_OFF_T = 1; then
+      REPLACE_FSEEKO=1
+    fi
+    if test $gl_cv_var_stdin_large_offset = no; then
+      REPLACE_FSEEKO=1
+    fi
+    m4_ifdef([gl_FUNC_FFLUSH_STDIN], [
+      gl_FUNC_FFLUSH_STDIN
+      case "$gl_cv_func_fflush_stdin" in
+        *yes) ;;
+        *) REPLACE_FSEEKO=1 ;;
+      esac
+    ])
+  fi
+])
+
+dnl Code shared by fseeko and ftello.  Determine if large files are supported,
+dnl but stdin does not start as a large file by default.
+AC_DEFUN([gl_STDIN_LARGE_OFFSET],
+  [
+    AC_CACHE_CHECK([whether stdin defaults to large file offsets],
+      [gl_cv_var_stdin_large_offset],
+      [AC_LINK_IFELSE([AC_LANG_PROGRAM([[#include <stdio.h>]],
+[[#if defined __SL64 && defined __SCLE /* cygwin */
+  /* Cygwin 1.5.24 and earlier fail to put stdin in 64-bit mode, making
+     fseeko/ftello needlessly fail.  This bug was fixed in 1.5.25, and
+     it is easier to do a version check than building a runtime test.  */
+# include <cygwin/version.h>
+# if CYGWIN_VERSION_DLL_COMBINED < CYGWIN_VERSION_DLL_MAKE_COMBINED (1005, 25)
+  choke me
+# endif
+#endif]])],
+        [gl_cv_var_stdin_large_offset=yes],
+        [gl_cv_var_stdin_large_offset=no])])
+])
+
+# Prerequisites of lib/fseeko.c.
+AC_DEFUN([gl_PREREQ_FSEEKO],
+[
+  dnl Native Windows has the function _fseeki64. mingw hides it in some
+  dnl circumstances, but mingw64 makes it usable again.
+  AC_CHECK_FUNCS([_fseeki64])
+  if test $ac_cv_func__fseeki64 = yes; then
+    AC_CHECK_DECLS([_fseeki64])
+  fi
+])
diff --git a/m4/fstat.m4 b/m4/fstat.m4
new file mode 100644
index 0000000..bd8cb79
--- /dev/null
+++ b/m4/fstat.m4
@@ -0,0 +1,40 @@
+# fstat.m4 serial 7
+dnl Copyright (C) 2011-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_FSTAT],
+[
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  AC_REQUIRE([gl_SYS_STAT_H_DEFAULTS])
+
+  case "$host_os" in
+    mingw* | solaris*)
+      dnl On MinGW, the original stat() returns st_atime, st_mtime,
+      dnl st_ctime values that are affected by the time zone.
+      dnl Solaris stat can return a negative tv_nsec.
+      REPLACE_FSTAT=1
+      ;;
+  esac
+
+  dnl Replace fstat() for supporting the gnulib-defined open() on directories.
+  m4_ifdef([gl_FUNC_FCHDIR], [
+    gl_TEST_FCHDIR
+    if test $HAVE_FCHDIR = 0; then
+      case "$gl_cv_func_open_directory_works" in
+        *yes) ;;
+        *)
+          REPLACE_FSTAT=1
+          ;;
+      esac
+    fi
+  ])
+])
+
+# Prerequisites of lib/fstat.c and lib/stat-w32.c.
+AC_DEFUN([gl_PREREQ_FSTAT], [
+  AC_REQUIRE([gl_HEADER_SYS_STAT_H])
+  AC_REQUIRE([gl_PREREQ_STAT_W32])
+  :
+])
diff --git a/m4/fstatat.m4 b/m4/fstatat.m4
new file mode 100644
index 0000000..19583ed
--- /dev/null
+++ b/m4/fstatat.m4
@@ -0,0 +1,65 @@
+# fstatat.m4 serial 4
+dnl Copyright (C) 2004-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+# Written by Jim Meyering.
+
+# If we have the fstatat function, and it has the bug (in AIX 7.1)
+# that it does not fill in st_size correctly, use the replacement function.
+AC_DEFUN([gl_FUNC_FSTATAT],
+[
+  AC_REQUIRE([gl_SYS_STAT_H_DEFAULTS])
+  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+  AC_REQUIRE([gl_FUNC_LSTAT_FOLLOWS_SLASHED_SYMLINK])
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  AC_CHECK_FUNCS_ONCE([fstatat])
+
+  if test $ac_cv_func_fstatat = no; then
+    HAVE_FSTATAT=0
+  else
+    dnl Test for an AIX 7.1 bug; see
+    dnl <https://lists.gnu.org/r/bug-tar/2011-09/msg00015.html>.
+    AC_CACHE_CHECK([whether fstatat (..., 0) works],
+      [gl_cv_func_fstatat_zero_flag],
+      [AC_RUN_IFELSE(
+         [AC_LANG_SOURCE(
+            [[
+              #include <fcntl.h>
+              #include <sys/stat.h>
+              int
+              main (void)
+              {
+                struct stat a;
+                return fstatat (AT_FDCWD, ".", &a, 0) != 0;
+              }
+            ]])],
+         [gl_cv_func_fstatat_zero_flag=yes],
+         [gl_cv_func_fstatat_zero_flag=no],
+         [case "$host_os" in
+            aix*) gl_cv_func_fstatat_zero_flag="guessing no";;
+            *)    gl_cv_func_fstatat_zero_flag="guessing yes";;
+          esac
+         ])
+      ])
+
+    case $gl_cv_func_fstatat_zero_flag+$gl_cv_func_lstat_dereferences_slashed_symlink in
+    *yes+*yes) ;;
+    *) REPLACE_FSTATAT=1 ;;
+    esac
+
+    case $host_os in
+      solaris*)
+        REPLACE_FSTATAT=1 ;;
+    esac
+
+    case $REPLACE_FSTATAT,$gl_cv_func_fstatat_zero_flag in
+      1,*yes)
+         AC_DEFINE([HAVE_WORKING_FSTATAT_ZERO_FLAG], [1],
+           [Define to 1 if fstatat (..., 0) works.
+            For example, it does not work in AIX 7.1.])
+         ;;
+    esac
+  fi
+])
diff --git a/m4/ftell.m4 b/m4/ftell.m4
new file mode 100644
index 0000000..22055d4
--- /dev/null
+++ b/m4/ftell.m4
@@ -0,0 +1,15 @@
+# ftell.m4 serial 3
+dnl Copyright (C) 2007, 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_FTELL],
+[
+  AC_REQUIRE([gl_STDIO_H_DEFAULTS])
+  AC_REQUIRE([gl_FUNC_FTELLO])
+  dnl When ftello needs fixes, ftell needs them too.
+  if test $HAVE_FTELLO = 0 || test $REPLACE_FTELLO = 1; then
+    REPLACE_FTELL=1
+  fi
+])
diff --git a/m4/ftello.m4 b/m4/ftello.m4
new file mode 100644
index 0000000..4c629c0
--- /dev/null
+++ b/m4/ftello.m4
@@ -0,0 +1,142 @@
+# ftello.m4 serial 13
+dnl Copyright (C) 2007-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_FTELLO],
+[
+  AC_REQUIRE([gl_STDIO_H_DEFAULTS])
+  AC_REQUIRE([AC_PROG_CC])
+  AC_REQUIRE([gl_STDIN_LARGE_OFFSET])
+  AC_REQUIRE([gl_SYS_TYPES_H])
+
+  dnl Persuade glibc <stdio.h> to declare ftello().
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
+
+  AC_CHECK_DECLS_ONCE([ftello])
+  if test $ac_cv_have_decl_ftello = no; then
+    HAVE_DECL_FTELLO=0
+  fi
+
+  AC_CACHE_CHECK([for ftello], [gl_cv_func_ftello],
+    [
+      AC_LINK_IFELSE(
+        [AC_LANG_PROGRAM(
+           [[#include <stdio.h>]],
+           [[ftello (stdin);]])],
+        [gl_cv_func_ftello=yes],
+        [gl_cv_func_ftello=no])
+    ])
+  if test $gl_cv_func_ftello = no; then
+    HAVE_FTELLO=0
+  else
+    if test $WINDOWS_64_BIT_OFF_T = 1; then
+      REPLACE_FTELLO=1
+    fi
+    if test $gl_cv_var_stdin_large_offset = no; then
+      REPLACE_FTELLO=1
+    fi
+    if test $REPLACE_FTELLO = 0; then
+      dnl Detect bug on Solaris.
+      dnl ftell and ftello produce incorrect results after putc that followed a
+      dnl getc call that reached EOF on Solaris. This is because the _IOREAD
+      dnl flag does not get cleared in this case, even though _IOWRT gets set,
+      dnl and ftell and ftello look whether the _IOREAD flag is set.
+      AC_REQUIRE([AC_CANONICAL_HOST])
+      AC_CACHE_CHECK([whether ftello works],
+        [gl_cv_func_ftello_works],
+        [
+          dnl Initial guess, used when cross-compiling or when /dev/tty cannot
+          dnl be opened.
+changequote(,)dnl
+          case "$host_os" in
+                      # Guess no on Solaris.
+            solaris*) gl_cv_func_ftello_works="guessing no" ;;
+                      # Guess yes on native Windows.
+            mingw*)   gl_cv_func_ftello_works="guessing yes" ;;
+                      # Guess yes otherwise.
+            *)        gl_cv_func_ftello_works="guessing yes" ;;
+          esac
+changequote([,])dnl
+          AC_RUN_IFELSE(
+            [AC_LANG_SOURCE([[
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#define TESTFILE "conftest.tmp"
+int
+main (void)
+{
+  FILE *fp;
+
+  /* Create a file with some contents.  */
+  fp = fopen (TESTFILE, "w");
+  if (fp == NULL)
+    return 70;
+  if (fwrite ("foogarsh", 1, 8, fp) < 8)
+    { fclose (fp); return 71; }
+  if (fclose (fp))
+    return 72;
+
+  /* The file's contents is now "foogarsh".  */
+
+  /* Try writing after reading to EOF.  */
+  fp = fopen (TESTFILE, "r+");
+  if (fp == NULL)
+    return 73;
+  if (fseek (fp, -1, SEEK_END))
+    { fclose (fp); return 74; }
+  if (!(getc (fp) == 'h'))
+    { fclose (fp); return 1; }
+  if (!(getc (fp) == EOF))
+    { fclose (fp); return 2; }
+  if (!(ftell (fp) == 8))
+    { fclose (fp); return 3; }
+  if (!(ftell (fp) == 8))
+    { fclose (fp); return 4; }
+  if (!(putc ('!', fp) == '!'))
+    { fclose (fp); return 5; }
+  if (!(ftell (fp) == 9))
+    { fclose (fp); return 6; }
+  if (!(fclose (fp) == 0))
+    return 7;
+  fp = fopen (TESTFILE, "r");
+  if (fp == NULL)
+    return 75;
+  {
+    char buf[10];
+    if (!(fread (buf, 1, 10, fp) == 9))
+      { fclose (fp); return 10; }
+    if (!(memcmp (buf, "foogarsh!", 9) == 0))
+      { fclose (fp); return 11; }
+  }
+  if (!(fclose (fp) == 0))
+    return 12;
+
+  /* The file's contents is now "foogarsh!".  */
+
+  return 0;
+}]])],
+            [gl_cv_func_ftello_works=yes],
+            [gl_cv_func_ftello_works=no], [:])
+        ])
+      case "$gl_cv_func_ftello_works" in
+        *yes) ;;
+        *)
+          REPLACE_FTELLO=1
+          AC_DEFINE([FTELLO_BROKEN_AFTER_SWITCHING_FROM_READ_TO_WRITE], [1],
+            [Define to 1 if the system's ftello function has the Solaris bug.])
+          ;;
+      esac
+    fi
+  fi
+])
+
+# Prerequisites of lib/ftello.c.
+AC_DEFUN([gl_PREREQ_FTELLO],
+[
+  dnl Native Windows has the function _ftelli64. mingw hides it, but mingw64
+  dnl makes it usable again.
+  AC_CHECK_FUNCS([_ftelli64])
+])
diff --git a/m4/futimens.m4 b/m4/futimens.m4
new file mode 100644
index 0000000..145b8ff
--- /dev/null
+++ b/m4/futimens.m4
@@ -0,0 +1,66 @@
+# serial 9
+# See if we need to provide futimens replacement.
+
+dnl Copyright (C) 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+# Written by Eric Blake.
+
+AC_DEFUN([gl_FUNC_FUTIMENS],
+[
+  AC_REQUIRE([gl_SYS_STAT_H_DEFAULTS])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+  AC_CHECK_FUNCS_ONCE([futimens])
+  if test $ac_cv_func_futimens = no; then
+    HAVE_FUTIMENS=0
+  else
+    AC_CACHE_CHECK([whether futimens works],
+      [gl_cv_func_futimens_works],
+      [AC_RUN_IFELSE([AC_LANG_PROGRAM([[
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <errno.h>
+]GL_MDA_DEFINES],
+     [[struct timespec ts[2];
+      int fd = creat ("conftest.file", 0600);
+      struct stat st;
+      if (fd < 0) return 1;
+      ts[0].tv_sec = 1;
+      ts[0].tv_nsec = UTIME_OMIT;
+      ts[1].tv_sec = 1;
+      ts[1].tv_nsec = UTIME_NOW;
+      errno = 0;
+      if (futimens (AT_FDCWD, NULL) == 0) return 2;
+      if (errno != EBADF) return 3;
+      if (futimens (fd, ts)) return 4;
+      sleep (1);
+      ts[0].tv_nsec = UTIME_NOW;
+      ts[1].tv_nsec = UTIME_OMIT;
+      if (futimens (fd, ts)) return 5;
+      if (fstat (fd, &st)) return 6;
+      if (st.st_ctime < st.st_atime) return 7;
+      ]])],
+         [gl_cv_func_futimens_works=yes],
+         [gl_cv_func_futimens_works=no],
+         [case "$host_os" in
+                           # Guess no on glibc systems.
+            *-gnu* | gnu*) gl_cv_func_futimens_works="guessing no" ;;
+                           # Guess no on musl systems.
+            *-musl*)       gl_cv_func_futimens_works="guessing no" ;;
+                           # Guess yes otherwise.
+            *)             gl_cv_func_futimens_works="guessing yes" ;;
+          esac
+         ])
+      rm -f conftest.file])
+    case "$gl_cv_func_futimens_works" in
+      *yes) ;;
+      *)
+        REPLACE_FUTIMENS=1
+        ;;
+    esac
+  fi
+])
diff --git a/m4/getaddrinfo.m4 b/m4/getaddrinfo.m4
new file mode 100644
index 0000000..b932f73
--- /dev/null
+++ b/m4/getaddrinfo.m4
@@ -0,0 +1,238 @@
+# getaddrinfo.m4 serial 33
+dnl Copyright (C) 2004-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_GETADDRINFO],
+[
+  AC_REQUIRE([gl_HEADER_SYS_SOCKET])dnl for HAVE_SYS_SOCKET_H, HAVE_WINSOCK2_H
+  AC_REQUIRE([gl_HEADER_NETDB])dnl for HAVE_NETDB_H
+  GETADDRINFO_LIB=
+  gai_saved_LIBS="$LIBS"
+
+  dnl Where is getaddrinfo()?
+  dnl - On Solaris, it is in libsocket.
+  dnl - On Haiku, it is in libnetwork.
+  dnl - On BeOS, it is in libnet.
+  dnl - On native Windows, it is in ws2_32.dll.
+  dnl - Otherwise it is in libc.
+  AC_SEARCH_LIBS([getaddrinfo], [socket network net],
+    [if test "$ac_cv_search_getaddrinfo" != "none required"; then
+       GETADDRINFO_LIB="$ac_cv_search_getaddrinfo"
+     fi])
+  LIBS="$gai_saved_LIBS $GETADDRINFO_LIB"
+
+  HAVE_GETADDRINFO=1
+  AC_CACHE_CHECK([for getaddrinfo], [gl_cv_func_getaddrinfo], [
+    AC_LINK_IFELSE([AC_LANG_PROGRAM([[
+#include <sys/types.h>
+#ifdef HAVE_SYS_SOCKET_H
+#include <sys/socket.h>
+#endif
+#ifdef HAVE_NETDB_H
+#include <netdb.h>
+#endif
+#include <stddef.h>
+]], [[getaddrinfo("", "", NULL, NULL);]])],
+      [gl_cv_func_getaddrinfo=yes],
+      [gl_cv_func_getaddrinfo=no])])
+  if test $gl_cv_func_getaddrinfo = no; then
+    AC_CACHE_CHECK([for getaddrinfo in ws2tcpip.h and -lws2_32],
+                   gl_cv_w32_getaddrinfo, [
+      gl_cv_w32_getaddrinfo=no
+      am_save_LIBS="$LIBS"
+      LIBS="$LIBS -lws2_32"
+      AC_LINK_IFELSE([AC_LANG_PROGRAM([[
+#ifdef HAVE_WS2TCPIP_H
+#include <ws2tcpip.h>
+#endif
+#include <stddef.h>
+]], [[getaddrinfo(NULL, NULL, NULL, NULL);]])], [gl_cv_w32_getaddrinfo=yes])
+      LIBS="$am_save_LIBS"
+    ])
+    if test "$gl_cv_w32_getaddrinfo" = "yes"; then
+      GETADDRINFO_LIB="-lws2_32"
+      LIBS="$gai_saved_LIBS $GETADDRINFO_LIB"
+      dnl Check for correct signature, in particular for a cdecl-compatible
+      dnl calling convention.
+      AC_CACHE_CHECK([for getaddrinfo with POSIX signature],
+        [gl_cv_func_getaddrinfo_posix_signature],
+        [AC_COMPILE_IFELSE([AC_LANG_SOURCE([[
+#include <sys/types.h>
+#ifdef HAVE_SYS_SOCKET_H
+#include <sys/socket.h>
+#endif
+#ifdef HAVE_NETDB_H
+#include <netdb.h>
+#endif
+#ifdef HAVE_WS2TCPIP_H
+#include <ws2tcpip.h>
+#endif
+#include <stddef.h>
+extern
+#ifdef __cplusplus
+"C"
+#endif
+int getaddrinfo (const char *, const char *, const struct addrinfo *, struct addrinfo **);
+]])],
+           [gl_cv_func_getaddrinfo_posix_signature=yes],
+           [gl_cv_func_getaddrinfo_posix_signature=no])
+        ])
+      if test $gl_cv_func_getaddrinfo_posix_signature = no; then
+        REPLACE_GETADDRINFO=1
+      fi
+    else
+      HAVE_GETADDRINFO=0
+    fi
+  fi
+  AC_DEFINE_UNQUOTED([HAVE_GETADDRINFO], [$HAVE_GETADDRINFO],
+    [Define to 1 if getaddrinfo exists, or to 0 otherwise.])
+
+  # We can't use AC_REPLACE_FUNCS here because gai_strerror may be an
+  # inline function declared in ws2tcpip.h, so we need to get that
+  # header included somehow.
+  AC_CHECK_DECLS([gai_strerror], [], [], [[
+#include <sys/types.h>
+#ifdef HAVE_SYS_SOCKET_H
+#include <sys/socket.h>
+#endif
+#ifdef HAVE_NETDB_H
+#include <netdb.h>
+#endif
+#ifdef HAVE_WS2TCPIP_H
+#include <ws2tcpip.h>
+#endif
+#include <stddef.h>
+]])
+  if test $ac_cv_have_decl_gai_strerror = yes; then
+    AC_CHECK_DECLS([gai_strerrorA], [], [], [[
+#include <sys/types.h>
+#ifdef HAVE_SYS_SOCKET_H
+#include <sys/socket.h>
+#endif
+#ifdef HAVE_NETDB_H
+#include <netdb.h>
+#endif
+#ifdef HAVE_WS2TCPIP_H
+#include <ws2tcpip.h>
+#endif
+#include <stddef.h>
+]])
+    dnl check for correct signature
+    AC_CACHE_CHECK([for gai_strerror with POSIX signature],
+     [gl_cv_func_gai_strerror_posix_signature], [
+      AC_COMPILE_IFELSE([AC_LANG_SOURCE([[
+#include <sys/types.h>
+#ifdef HAVE_SYS_SOCKET_H
+#include <sys/socket.h>
+#endif
+#ifdef HAVE_NETDB_H
+#include <netdb.h>
+#endif
+#ifdef HAVE_WS2TCPIP_H
+#include <ws2tcpip.h>
+#endif
+#include <stddef.h>
+extern
+#ifdef __cplusplus
+"C"
+#endif
+const char *gai_strerror(int);]])],
+        [gl_cv_func_gai_strerror_posix_signature=yes],
+        [gl_cv_func_gai_strerror_posix_signature=no])])
+    if test $gl_cv_func_gai_strerror_posix_signature = no; then
+      REPLACE_GAI_STRERROR=1
+    fi
+  fi
+
+  LIBS="$gai_saved_LIBS"
+
+  gl_PREREQ_GETADDRINFO
+
+  AC_SUBST([GETADDRINFO_LIB])
+])
+
+# Prerequisites of lib/netdb.in.h and lib/getaddrinfo.c.
+AC_DEFUN([gl_PREREQ_GETADDRINFO], [
+  AC_REQUIRE([gl_NETDB_H_DEFAULTS])
+  AC_REQUIRE([gl_HEADER_SYS_SOCKET])dnl for HAVE_SYS_SOCKET_H, HAVE_WINSOCK2_H
+  AC_REQUIRE([gl_HOSTENT]) dnl for HOSTENT_LIB
+  AC_REQUIRE([gl_SERVENT]) dnl for SERVENT_LIB
+  AC_REQUIRE([gl_FUNC_INET_NTOP]) dnl for INET_NTOP_LIB
+  AC_REQUIRE([AC_C_RESTRICT])
+  AC_REQUIRE([gl_SOCKET_FAMILIES])
+  AC_REQUIRE([gl_HEADER_SYS_SOCKET])
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
+
+  dnl Including sys/socket.h is wrong for Windows, but Windows does not
+  dnl have sa_len so the result is correct anyway.
+  AC_CHECK_MEMBERS([struct sockaddr.sa_len], , , [
+#include <sys/types.h>
+#include <sys/socket.h>
+])
+
+  AC_CHECK_HEADERS_ONCE([netinet/in.h])
+
+  AC_CHECK_DECLS([getaddrinfo, freeaddrinfo, getnameinfo],,,[[
+  /* sys/types.h is not needed according to POSIX, but the
+     sys/socket.h in i386-unknown-freebsd4.10 and
+     powerpc-apple-darwin5.5 required it. */
+#include <sys/types.h>
+#ifdef HAVE_SYS_SOCKET_H
+#include <sys/socket.h>
+#endif
+#ifdef HAVE_NETDB_H
+#include <netdb.h>
+#endif
+#ifdef HAVE_WS2TCPIP_H
+#include <ws2tcpip.h>
+#endif
+]])
+  if test $ac_cv_have_decl_getaddrinfo = no; then
+    HAVE_DECL_GETADDRINFO=0
+  fi
+  if test $ac_cv_have_decl_freeaddrinfo = no; then
+    HAVE_DECL_FREEADDRINFO=0
+  fi
+  if test $ac_cv_have_decl_gai_strerror = no; then
+    HAVE_DECL_GAI_STRERROR=0
+  fi
+  if test $ac_cv_have_decl_getnameinfo = no; then
+    HAVE_DECL_GETNAMEINFO=0
+  fi
+
+  AC_CHECK_TYPES([struct addrinfo],,,[
+#include <sys/types.h>
+#ifdef HAVE_SYS_SOCKET_H
+#include <sys/socket.h>
+#endif
+#ifdef HAVE_NETDB_H
+#include <netdb.h>
+#endif
+#ifdef HAVE_WS2TCPIP_H
+#include <ws2tcpip.h>
+#endif
+])
+  if test $ac_cv_type_struct_addrinfo = no; then
+    HAVE_STRUCT_ADDRINFO=0
+  fi
+
+  dnl Append $HOSTENT_LIB to GETADDRINFO_LIB, avoiding gratuitous duplicates.
+  case " $GETADDRINFO_LIB " in
+    *" $HOSTENT_LIB "*) ;;
+    *) GETADDRINFO_LIB="$GETADDRINFO_LIB $HOSTENT_LIB" ;;
+  esac
+
+  dnl Append $SERVENT_LIB to GETADDRINFO_LIB, avoiding gratuitous duplicates.
+  case " $GETADDRINFO_LIB " in
+    *" $SERVENT_LIB "*) ;;
+    *) GETADDRINFO_LIB="$GETADDRINFO_LIB $SERVENT_LIB" ;;
+  esac
+
+  dnl Append $INET_NTOP_LIB to GETADDRINFO_LIB, avoiding gratuitous duplicates.
+  case " $GETADDRINFO_LIB " in
+    *" $INET_NTOP_LIB "*) ;;
+    *) GETADDRINFO_LIB="$GETADDRINFO_LIB $INET_NTOP_LIB" ;;
+  esac
+])
diff --git a/m4/getcwd-abort-bug.m4 b/m4/getcwd-abort-bug.m4
new file mode 100644
index 0000000..b5cf86e
--- /dev/null
+++ b/m4/getcwd-abort-bug.m4
@@ -0,0 +1,159 @@
+# serial 15
+# Determine whether getcwd aborts when the length of the working directory
+# name is unusually large.  Any length between 4k and 16k trigger the bug
+# when using glibc-2.4.90-9 or older.
+
+# Copyright (C) 2006, 2009-2020 Free Software Foundation, Inc.
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+# From Jim Meyering
+
+# gl_FUNC_GETCWD_ABORT_BUG([ACTION-IF-BUGGY[, ACTION-IF-WORKS]])
+AC_DEFUN([gl_FUNC_GETCWD_ABORT_BUG],
+[
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_CHECK_DECLS_ONCE([getcwd])
+  AC_CHECK_HEADERS_ONCE([unistd.h])
+  AC_REQUIRE([gl_PATHMAX_SNIPPET_PREREQ])
+
+  gl_CHECK_FUNC_GETPAGESIZE
+  if test $gl_cv_func_getpagesize = yes; then
+    AC_DEFINE_UNQUOTED([HAVE_GETPAGESIZE], [1],
+      [Define to 1 if the system has the 'getpagesize' function.])
+  fi
+
+  AC_CACHE_CHECK([whether getcwd succeeds when 4k < cwd_length < 16k],
+    [gl_cv_func_getcwd_succeeds_beyond_4k],
+    [# Remove any remnants of a previous test.
+     rm -rf confdir-14B---
+     # Arrange for deletion of the temporary directory this test creates.
+     ac_clean_files="$ac_clean_files confdir-14B---"
+     dnl Please keep this in sync with tests/test-getcwd.c.
+     AC_RUN_IFELSE(
+       [AC_LANG_SOURCE(
+          [[
+#include <errno.h>
+#include <stdlib.h>
+#if HAVE_UNISTD_H
+# include <unistd.h>
+#else /* on Windows with MSVC */
+# include <direct.h>
+#endif
+#include <string.h>
+#include <sys/stat.h>
+
+]gl_PATHMAX_SNIPPET[
+]GL_MDA_DEFINES[
+
+#ifndef S_IRWXU
+# define S_IRWXU 0700
+#endif
+
+/* FIXME: skip the run-test altogether on systems without getpagesize.  */
+#if ! HAVE_GETPAGESIZE
+# define getpagesize() 0
+#endif
+
+/* This size is chosen to be larger than PATH_MAX (4k), yet smaller than
+   the 16kB pagesize on ia64 linux.  Those conditions make the code below
+   trigger a bug in glibc's getcwd implementation before 2.4.90-10.  */
+#define TARGET_LEN (5 * 1024)
+
+int
+main ()
+{
+  char *cwd;
+  size_t initial_cwd_len;
+  int fail = 0;
+
+  /* The bug is triggered when PATH_MAX < getpagesize (), so skip
+     this relatively expensive and invasive test if that's not true.  */
+#ifdef PATH_MAX
+  int bug_possible = PATH_MAX < getpagesize ();
+#else
+  int bug_possible = 0;
+#endif
+  if (! bug_possible)
+    return 0;
+
+  cwd = getcwd (NULL, 0);
+  if (cwd == NULL)
+    return 2;
+
+  initial_cwd_len = strlen (cwd);
+  free (cwd);
+
+  if (1)
+    {
+      static char const dir_name[] = "confdir-14B---";
+      size_t desired_depth = ((TARGET_LEN - 1 - initial_cwd_len)
+                              / sizeof dir_name);
+      size_t d;
+      for (d = 0; d < desired_depth; d++)
+        {
+          if (mkdir (dir_name, S_IRWXU) < 0 || chdir (dir_name) < 0)
+            {
+              if (! (errno == ERANGE || errno == ENAMETOOLONG
+                     || errno == ENOENT))
+                fail = 3; /* Unable to construct deep hierarchy.  */
+              break;
+            }
+        }
+
+      /* If libc has the bug in question, this invocation of getcwd
+         results in a failed assertion.  */
+      cwd = getcwd (NULL, 0);
+      if (cwd == NULL)
+        fail = 4; /* getcwd didn't assert, but it failed for a long name
+                     where the answer could have been learned.  */
+      free (cwd);
+
+      /* Call rmdir first, in case the above chdir failed.  */
+      rmdir (dir_name);
+      while (0 < d--)
+        {
+          if (chdir ("..") < 0)
+            {
+              fail = 5;
+              break;
+            }
+          rmdir (dir_name);
+        }
+    }
+
+  return fail;
+}
+          ]])],
+       [gl_cv_func_getcwd_succeeds_beyond_4k=yes],
+       [dnl An abort will provoke an exit code of something like 134 (128 + 6).
+        dnl An exit code of 4 can also occur (in OpenBSD 6.7, NetBSD 5.1 for
+        dnl example): getcwd (NULL, 0) fails rather than returning a string
+        dnl longer than PATH_MAX.  This may be POSIX compliant (in some
+        dnl interpretations of POSIX).  But gnulib's getcwd module wants to
+        dnl provide a non-NULL value in this case.
+        ret=$?
+        if test $ret -ge 128 || test $ret = 4; then
+          gl_cv_func_getcwd_succeeds_beyond_4k=no
+        else
+          gl_cv_func_getcwd_succeeds_beyond_4k=yes
+        fi
+       ],
+       [case "$host_os" in
+                   # Guess yes on musl systems.
+          *-musl*) gl_cv_func_getcwd_succeeds_beyond_4k="guessing yes" ;;
+                   # Guess no otherwise, even on glibc systems.
+          *)       gl_cv_func_getcwd_succeeds_beyond_4k="guessing no"
+        esac
+       ])
+    ])
+  case "$gl_cv_func_getcwd_succeeds_beyond_4k" in
+    *no)
+      $1
+      ;;
+    *)
+      $2
+      ;;
+  esac
+])
diff --git a/m4/getcwd-path-max.m4 b/m4/getcwd-path-max.m4
new file mode 100644
index 0000000..859c7de
--- /dev/null
+++ b/m4/getcwd-path-max.m4
@@ -0,0 +1,236 @@
+# serial 25
+# Check for several getcwd bugs with long file names.
+# If so, arrange to compile the wrapper function.
+
+# This is necessary for at least GNU libc on linux-2.4.19 and 2.4.20.
+# I've heard that this is due to a Linux kernel bug, and that it has
+# been fixed between 2.4.21-pre3 and 2.4.21-pre4.
+
+# Copyright (C) 2003-2007, 2009-2020 Free Software Foundation, Inc.
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+# From Jim Meyering
+
+AC_DEFUN([gl_FUNC_GETCWD_PATH_MAX],
+[
+  AC_CHECK_DECLS_ONCE([getcwd])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+  AC_CHECK_HEADERS_ONCE([unistd.h])
+  AC_REQUIRE([gl_PATHMAX_SNIPPET_PREREQ])
+  AC_CACHE_CHECK([whether getcwd handles long file names properly],
+    [gl_cv_func_getcwd_path_max],
+    [# Arrange for deletion of the temporary directory this test creates.
+     ac_clean_files="$ac_clean_files confdir3"
+     dnl Please keep this in sync with tests/test-getcwd.c.
+     AC_RUN_IFELSE(
+       [AC_LANG_SOURCE(
+          [[
+#include <errno.h>
+#include <stdlib.h>
+#if HAVE_UNISTD_H
+# include <unistd.h>
+#else
+# include <direct.h>
+#endif
+#include <string.h>
+#include <limits.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <fcntl.h>
+
+]gl_PATHMAX_SNIPPET[
+
+#ifndef AT_FDCWD
+# define AT_FDCWD 0
+#endif
+#ifdef ENAMETOOLONG
+# define is_ENAMETOOLONG(x) ((x) == ENAMETOOLONG)
+#else
+# define is_ENAMETOOLONG(x) 0
+#endif
+
+/* Use the getcwd function, not any macro.  */
+#undef getcwd
+
+]GL_MDA_DEFINES[
+
+#ifndef S_IRWXU
+# define S_IRWXU 0700
+#endif
+
+/* The length of this name must be 8.  */
+#define DIR_NAME "confdir3"
+#define DIR_NAME_LEN 8
+#define DIR_NAME_SIZE (DIR_NAME_LEN + 1)
+
+/* The length of "../".  */
+#define DOTDOTSLASH_LEN 3
+
+/* Leftover bytes in the buffer, to work around library or OS bugs.  */
+#define BUF_SLOP 20
+
+int
+main ()
+{
+#ifndef PATH_MAX
+  /* The Hurd doesn't define this, so getcwd can't exhibit the bug --
+     at least not on a local file system.  And if we were to start worrying
+     about remote file systems, we'd have to enable the wrapper function
+     all of the time, just to be safe.  That's not worth the cost.  */
+  exit (0);
+#elif ((INT_MAX / (DIR_NAME_SIZE / DOTDOTSLASH_LEN + 1) \
+        - DIR_NAME_SIZE - BUF_SLOP) \
+       <= PATH_MAX)
+  /* FIXME: Assuming there's a system for which this is true,
+     this should be done in a compile test.  */
+  exit (0);
+#else
+  char buf[PATH_MAX * (DIR_NAME_SIZE / DOTDOTSLASH_LEN + 1)
+           + DIR_NAME_SIZE + BUF_SLOP];
+  char *cwd = getcwd (buf, PATH_MAX);
+  size_t initial_cwd_len;
+  size_t cwd_len;
+  int fail = 0;
+  size_t n_chdirs = 0;
+
+  if (cwd == NULL)
+    exit (10);
+
+  cwd_len = initial_cwd_len = strlen (cwd);
+
+  while (1)
+    {
+      size_t dotdot_max = PATH_MAX * (DIR_NAME_SIZE / DOTDOTSLASH_LEN);
+      char *c = NULL;
+
+      cwd_len += DIR_NAME_SIZE;
+      /* If mkdir or chdir fails, it could be that this system cannot create
+         any file with an absolute name longer than PATH_MAX, such as cygwin.
+         If so, leave fail as 0, because the current working directory can't
+         be too long for getcwd if it can't even be created.  On Linux with
+         the 9p file system, mkdir fails with error EINVAL when cwd_len gets
+         too long; ignore this failure because the getcwd() system call
+         produces good results whereas the gnulib substitute calls getdents64
+         which fails with error EPROTO.
+         For other errors, be pessimistic and consider that as a failure,
+         too.  */
+      if (mkdir (DIR_NAME, S_IRWXU) < 0 || chdir (DIR_NAME) < 0)
+        {
+          if (! (errno == ERANGE || is_ENAMETOOLONG (errno)))
+            #ifdef __linux__
+            if (! (errno == EINVAL))
+            #endif
+              fail = 20;
+          break;
+        }
+
+      if (PATH_MAX <= cwd_len && cwd_len < PATH_MAX + DIR_NAME_SIZE)
+        {
+          struct stat sb;
+
+          c = getcwd (buf, PATH_MAX);
+          if (!c && errno == ENOENT)
+            {
+              fail = 11;
+              break;
+            }
+          if (c)
+            {
+              fail = 31;
+              break;
+            }
+          if (! (errno == ERANGE || is_ENAMETOOLONG (errno)))
+            {
+              fail = 21;
+              break;
+            }
+
+          /* Our replacement needs to be able to stat() long ../../paths,
+             so generate a path larger than PATH_MAX to check,
+             avoiding the replacement if we can't stat().  */
+          c = getcwd (buf, cwd_len + 1);
+          if (c && !AT_FDCWD && stat (c, &sb) != 0 && is_ENAMETOOLONG (errno))
+            {
+              fail = 32;
+              break;
+            }
+        }
+
+      if (dotdot_max <= cwd_len - initial_cwd_len)
+        {
+          if (dotdot_max + DIR_NAME_SIZE < cwd_len - initial_cwd_len)
+            break;
+          c = getcwd (buf, cwd_len + 1);
+          if (!c)
+            {
+              if (! (errno == ERANGE || errno == ENOENT
+                     || is_ENAMETOOLONG (errno)))
+                {
+                  fail = 22;
+                  break;
+                }
+              if (AT_FDCWD || errno == ERANGE || errno == ENOENT)
+                {
+                  fail = 12;
+                  break;
+                }
+            }
+        }
+
+      if (c && strlen (c) != cwd_len)
+        {
+          fail = 23;
+          break;
+        }
+      ++n_chdirs;
+    }
+
+  /* Leaving behind such a deep directory is not polite.
+     So clean up here, right away, even though the driving
+     shell script would also clean up.  */
+  {
+    size_t i;
+
+    /* Try rmdir first, in case the chdir failed.  */
+    rmdir (DIR_NAME);
+    for (i = 0; i <= n_chdirs; i++)
+      {
+        if (chdir ("..") < 0)
+          break;
+        if (rmdir (DIR_NAME) != 0)
+          break;
+      }
+  }
+
+  exit (fail);
+#endif
+}
+          ]])],
+       [gl_cv_func_getcwd_path_max=yes],
+       [case $? in
+        10|11|12) gl_cv_func_getcwd_path_max='no, but it is partly working';;
+        31) gl_cv_func_getcwd_path_max='no, it has the AIX bug';;
+        32) gl_cv_func_getcwd_path_max='yes, but with shorter paths';;
+        *) gl_cv_func_getcwd_path_max=no;;
+        esac],
+       [# Cross-compilation guesses:
+        case "$host_os" in
+          aix*) # On AIX, it has the AIX bug.
+            gl_cv_func_getcwd_path_max='guessing no, it has the AIX bug' ;;
+          gnu*) # On Hurd, it is 'yes'.
+            gl_cv_func_getcwd_path_max='guessing yes' ;;
+          linux* | kfreebsd*)
+            # On older Linux+glibc it's 'no, but it is partly working',
+            # on newer Linux+glibc it's 'yes'.
+            # On Linux+musl libc, it's 'no, but it is partly working'.
+            # On kFreeBSD+glibc, it's 'no, but it is partly working'.
+            gl_cv_func_getcwd_path_max='guessing no, but it is partly working' ;;
+          *) # If we don't know, obey --enable-cross-guesses.
+            gl_cv_func_getcwd_path_max="$gl_cross_guess_normal" ;;
+        esac
+       ])
+    ])
+])
diff --git a/m4/getcwd.m4 b/m4/getcwd.m4
new file mode 100644
index 0000000..a646b90
--- /dev/null
+++ b/m4/getcwd.m4
@@ -0,0 +1,166 @@
+# getcwd.m4 - check for working getcwd that is compatible with glibc
+
+# Copyright (C) 2001, 2003-2007, 2009-2020 Free Software Foundation, Inc.
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+# Written by Paul Eggert.
+# serial 19
+
+AC_DEFUN([gl_FUNC_GETCWD_NULL],
+  [
+   AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+   AC_CHECK_HEADERS_ONCE([unistd.h])
+   AC_CACHE_CHECK([whether getcwd (NULL, 0) allocates memory for result],
+     [gl_cv_func_getcwd_null],
+     [AC_RUN_IFELSE([AC_LANG_PROGRAM([[
+#	 include <stdlib.h>
+#        if HAVE_UNISTD_H
+#         include <unistd.h>
+#        else /* on Windows with MSVC */
+#         include <direct.h>
+#        endif
+         ]GL_MDA_DEFINES[
+#        ifndef getcwd
+         char *getcwd ();
+#        endif
+]], [[
+#if defined _WIN32 && ! defined __CYGWIN__
+/* mingw cwd does not start with '/', but _getcwd does allocate.
+   However, mingw fails to honor non-zero size.  */
+#else
+           if (chdir ("/") != 0)
+             return 1;
+           else
+             {
+               char *f = getcwd (NULL, 0);
+               if (! f)
+                 return 2;
+               if (f[0] != '/')
+                 { free (f); return 3; }
+               if (f[1] != '\0')
+                 { free (f); return 4; }
+               free (f);
+               return 0;
+             }
+#endif
+         ]])],
+        [gl_cv_func_getcwd_null=yes],
+        [gl_cv_func_getcwd_null=no],
+        [[case "$host_os" in
+                           # Guess yes on glibc systems.
+            *-gnu* | gnu*) gl_cv_func_getcwd_null="guessing yes";;
+                           # Guess yes on musl systems.
+            *-musl*)       gl_cv_func_getcwd_null="guessing yes";;
+                           # Guess yes on Cygwin.
+            cygwin*)       gl_cv_func_getcwd_null="guessing yes";;
+                           # If we don't know, obey --enable-cross-guesses.
+            *)             gl_cv_func_getcwd_null="$gl_cross_guess_normal";;
+          esac
+        ]])])
+])
+
+AC_DEFUN([gl_FUNC_GETCWD_SIGNATURE],
+[
+  AC_CACHE_CHECK([for getcwd with POSIX signature],
+    [gl_cv_func_getcwd_posix_signature],
+    [AC_COMPILE_IFELSE(
+      [AC_LANG_PROGRAM(
+         [[#include <unistd.h>
+         ]GL_MDA_DEFINES],
+         [[extern
+           #ifdef __cplusplus
+           "C"
+           #endif
+           char *getcwd (char *, size_t);
+         ]])
+      ],
+      [gl_cv_func_getcwd_posix_signature=yes],
+      [gl_cv_func_getcwd_posix_signature=no])
+   ])
+])
+
+dnl Guarantee that getcwd will malloc with a NULL first argument.  Assumes
+dnl that either the system getcwd is robust, or that calling code is okay
+dnl with spurious failures when run from a directory with an absolute name
+dnl larger than 4k bytes.
+dnl
+dnl Assumes that getcwd exists; if you are worried about obsolete
+dnl platforms that lacked getcwd(), then you need to use the GPL module.
+AC_DEFUN([gl_FUNC_GETCWD_LGPL],
+[
+  AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
+  AC_REQUIRE([gl_FUNC_GETCWD_NULL])
+  AC_REQUIRE([gl_FUNC_GETCWD_SIGNATURE])
+
+  case $gl_cv_func_getcwd_null,$gl_cv_func_getcwd_posix_signature in
+  *yes,yes) ;;
+  *)
+    dnl Minimal replacement lib/getcwd-lgpl.c.
+    REPLACE_GETCWD=1
+    ;;
+  esac
+])
+
+dnl Check for all known getcwd bugs; useful for a program likely to be
+dnl executed from an arbitrary location.
+AC_DEFUN([gl_FUNC_GETCWD],
+[
+  AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
+  AC_REQUIRE([gl_FUNC_GETCWD_NULL])
+  AC_REQUIRE([gl_FUNC_GETCWD_SIGNATURE])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+
+  gl_abort_bug=no
+  case "$host_os" in
+    mingw*)
+      gl_cv_func_getcwd_path_max=yes
+      ;;
+    *)
+      gl_FUNC_GETCWD_PATH_MAX
+      case "$gl_cv_func_getcwd_null" in
+        *yes)
+          gl_FUNC_GETCWD_ABORT_BUG([gl_abort_bug=yes])
+          ;;
+      esac
+      ;;
+  esac
+  dnl Define HAVE_MINIMALLY_WORKING_GETCWD and HAVE_PARTLY_WORKING_GETCWD
+  dnl if appropriate.
+  case "$gl_cv_func_getcwd_path_max" in
+    *"no" | *"no, it has the AIX bug") ;;
+    *)
+      AC_DEFINE([HAVE_MINIMALLY_WORKING_GETCWD], [1],
+        [Define to 1 if getcwd minimally works, that is, its result can be
+         trusted when it succeeds.])
+      ;;
+  esac
+  case "$gl_cv_func_getcwd_path_max" in
+    *"no, but it is partly working")
+      AC_DEFINE([HAVE_PARTLY_WORKING_GETCWD], [1],
+        [Define to 1 if getcwd works, except it sometimes fails when it
+         shouldn't, setting errno to ERANGE, ENAMETOOLONG, or ENOENT.])
+      ;;
+    *"yes, but with shorter paths")
+      AC_DEFINE([HAVE_GETCWD_SHORTER], [1],
+        [Define to 1 if getcwd works, but with shorter paths
+         than is generally tested with the replacement.])
+      ;;
+  esac
+
+  if { case "$gl_cv_func_getcwd_null" in *yes) false;; *) true;; esac; } \
+     || test $gl_cv_func_getcwd_posix_signature != yes \
+     || { case "$gl_cv_func_getcwd_path_max" in *yes*) false;; *) true;; esac; } \
+     || test $gl_abort_bug = yes; then
+    REPLACE_GETCWD=1
+  fi
+])
+
+# Prerequisites of lib/getcwd.c, when full replacement is in effect.
+AC_DEFUN([gl_PREREQ_GETCWD],
+[
+  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+  AC_REQUIRE([gl_CHECK_TYPE_STRUCT_DIRENT_D_INO])
+  :
+])
diff --git a/m4/getdelim.m4 b/m4/getdelim.m4
new file mode 100644
index 0000000..ac3917b
--- /dev/null
+++ b/m4/getdelim.m4
@@ -0,0 +1,99 @@
+# getdelim.m4 serial 15
+
+dnl Copyright (C) 2005-2007, 2009-2020 Free Software Foundation, Inc.
+dnl
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_PREREQ([2.59])
+
+AC_DEFUN([gl_FUNC_GETDELIM],
+[
+  AC_REQUIRE([gl_STDIO_H_DEFAULTS])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+
+  dnl Persuade glibc <stdio.h> to declare getdelim().
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
+
+  AC_CHECK_DECLS_ONCE([getdelim])
+
+  AC_CHECK_FUNCS_ONCE([getdelim])
+  if test $ac_cv_func_getdelim = yes; then
+    HAVE_GETDELIM=1
+    dnl Found it in some library.  Verify that it works.
+    AC_CACHE_CHECK([for working getdelim function],
+      [gl_cv_func_working_getdelim],
+      [echo fooNbarN | tr -d '\012' | tr N '\012' > conftest.data
+       AC_RUN_IFELSE([AC_LANG_SOURCE([[
+#    include <stdio.h>
+#    include <stdlib.h>
+#    include <string.h>
+    int main ()
+    {
+      FILE *in = fopen ("./conftest.data", "r");
+      if (!in)
+        return 1;
+      {
+        /* Test result for a NULL buffer and a zero size.
+           Based on a test program from Karl Heuer.  */
+        char *line = NULL;
+        size_t siz = 0;
+        int len = getdelim (&line, &siz, '\n', in);
+        if (!(len == 4 && line && strcmp (line, "foo\n") == 0))
+          { free (line); fclose (in); return 2; }
+        free (line);
+      }
+      {
+        /* Test result for a NULL buffer and a non-zero size.
+           This crashes on FreeBSD 8.0.  */
+        char *line = NULL;
+        size_t siz = (size_t)(~0) / 4;
+        if (getdelim (&line, &siz, '\n', in) == -1)
+          { fclose (in); return 3; }
+        free (line);
+      }
+      fclose (in);
+      return 0;
+    }
+    ]])],
+         [gl_cv_func_working_getdelim=yes],
+         [gl_cv_func_working_getdelim=no],
+         [dnl We're cross compiling.
+          dnl Guess it works on glibc2 systems and musl systems.
+          AC_EGREP_CPP([Lucky GNU user],
+            [
+#include <features.h>
+#ifdef __GNU_LIBRARY__
+ #if (__GLIBC__ >= 2) && !defined __UCLIBC__
+  Lucky GNU user
+ #endif
+#endif
+            ],
+            [gl_cv_func_working_getdelim="guessing yes"],
+            [case "$host_os" in
+               *-musl*) gl_cv_func_working_getdelim="guessing yes" ;;
+               *)       gl_cv_func_working_getdelim="$gl_cross_guess_normal" ;;
+             esac
+            ])
+         ])
+      ])
+    case "$gl_cv_func_working_getdelim" in
+      *yes) ;;
+      *) REPLACE_GETDELIM=1 ;;
+    esac
+  else
+    HAVE_GETDELIM=0
+  fi
+
+  if test $ac_cv_have_decl_getdelim = no; then
+    HAVE_DECL_GETDELIM=0
+  fi
+])
+
+# Prerequisites of lib/getdelim.c.
+AC_DEFUN([gl_PREREQ_GETDELIM],
+[
+  AC_CHECK_FUNCS([flockfile funlockfile])
+  AC_CHECK_DECLS([getc_unlocked])
+])
diff --git a/m4/getdtablesize.m4 b/m4/getdtablesize.m4
new file mode 100644
index 0000000..af32864
--- /dev/null
+++ b/m4/getdtablesize.m4
@@ -0,0 +1,63 @@
+# getdtablesize.m4 serial 8
+dnl Copyright (C) 2008-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_GETDTABLESIZE],
+[
+  AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  AC_CHECK_FUNCS_ONCE([getdtablesize])
+  AC_CHECK_DECLS_ONCE([getdtablesize])
+  if test $ac_cv_func_getdtablesize = yes &&
+     test $ac_cv_have_decl_getdtablesize = yes; then
+    AC_CACHE_CHECK([whether getdtablesize works],
+      [gl_cv_func_getdtablesize_works],
+      [dnl There are two concepts: the "maximum possible file descriptor value + 1"
+       dnl and the "maximum number of open file descriptors in a process".
+       dnl Per SUSv2 and POSIX, getdtablesize() should return the first one.
+       dnl On most platforms, the first and the second concept are the same.
+       dnl On OpenVMS, however, they are different and getdtablesize() returns
+       dnl the second one; thus the test below fails. But we don't care
+       dnl because there's no good way to write a replacement getdtablesize().
+       case "$host_os" in
+         vms*) gl_cv_func_getdtablesize_works="no (limitation)" ;;
+         *)
+           dnl Cygwin 1.7.25 automatically increases the RLIMIT_NOFILE soft
+           dnl limit up to an unchangeable hard limit; all other platforms
+           dnl correctly require setrlimit before getdtablesize() can report
+           dnl a larger value.
+           AC_RUN_IFELSE([
+             AC_LANG_PROGRAM(
+               [[#include <unistd.h>]
+                GL_MDA_DEFINES
+               ],
+               [[int size = getdtablesize();
+                 if (dup2 (0, getdtablesize()) != -1)
+                   return 1;
+                 if (size != getdtablesize())
+                   return 2;
+               ]])],
+             [gl_cv_func_getdtablesize_works=yes],
+             [gl_cv_func_getdtablesize_works=no],
+             [case "$host_os" in
+                cygwin*) # on cygwin 1.5.25, getdtablesize() automatically grows
+                  gl_cv_func_getdtablesize_works="guessing no" ;;
+                *) gl_cv_func_getdtablesize_works="guessing yes" ;;
+              esac
+             ])
+           ;;
+       esac
+      ])
+    case "$gl_cv_func_getdtablesize_works" in
+      *yes | "no (limitation)") ;;
+      *) REPLACE_GETDTABLESIZE=1 ;;
+    esac
+  else
+    HAVE_GETDTABLESIZE=0
+  fi
+])
+
+# Prerequisites of lib/getdtablesize.c.
+AC_DEFUN([gl_PREREQ_GETDTABLESIZE], [:])
diff --git a/m4/getgroups.m4 b/m4/getgroups.m4
new file mode 100644
index 0000000..e344162
--- /dev/null
+++ b/m4/getgroups.m4
@@ -0,0 +1,110 @@
+# serial 24
+
+dnl From Jim Meyering.
+dnl A wrapper around AC_FUNC_GETGROUPS.
+
+# Copyright (C) 1996-1997, 1999-2004, 2008-2020 Free Software Foundation, Inc.
+#
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+# This is taken from the following Autoconf patch:
+# https://git.savannah.gnu.org/gitweb/?p=autoconf.git;a=commitdiff;h=7fbb553727ed7e0e689a17594b58559ecf3ea6e9
+AC_DEFUN([AC_FUNC_GETGROUPS],
+[
+  AC_REQUIRE([AC_TYPE_GETGROUPS])dnl
+  AC_REQUIRE([AC_TYPE_SIZE_T])dnl
+  AC_REQUIRE([AC_CANONICAL_HOST])dnl for cross-compiles
+  AC_CHECK_FUNC([getgroups])
+
+  # If we don't yet have getgroups, see if it's in -lbsd.
+  # This is reported to be necessary on an ITOS 3000WS running SEIUX 3.1.
+  ac_save_LIBS=$LIBS
+  if test $ac_cv_func_getgroups = no; then
+    AC_CHECK_LIB(bsd, getgroups, [GETGROUPS_LIB=-lbsd])
+  fi
+
+  # Run the program to test the functionality of the system-supplied
+  # getgroups function only if there is such a function.
+  if test $ac_cv_func_getgroups = yes; then
+    AC_CACHE_CHECK([for working getgroups], [ac_cv_func_getgroups_works],
+      [AC_RUN_IFELSE(
+         [AC_LANG_PROGRAM(
+            [AC_INCLUDES_DEFAULT],
+            [[/* On NeXTstep 3.2, getgroups (0, 0) always fails.  */
+              return getgroups (0, 0) == -1;]])
+         ],
+         [ac_cv_func_getgroups_works=yes],
+         [ac_cv_func_getgroups_works=no],
+         [case "$host_os" in # ((
+                           # Guess yes on glibc systems.
+            *-gnu* | gnu*) ac_cv_func_getgroups_works="guessing yes" ;;
+                           # Guess yes on musl systems.
+            *-musl*)       ac_cv_func_getgroups_works="guessing yes" ;;
+                           # If we don't know, obey --enable-cross-guesses.
+            *)             ac_cv_func_getgroups_works="$gl_cross_guess_normal" ;;
+          esac
+         ])
+      ])
+  else
+    ac_cv_func_getgroups_works=no
+  fi
+  case "$ac_cv_func_getgroups_works" in
+    *yes)
+      AC_DEFINE([HAVE_GETGROUPS], [1],
+        [Define to 1 if your system has a working `getgroups' function.])
+      ;;
+  esac
+  LIBS=$ac_save_LIBS
+])# AC_FUNC_GETGROUPS
+
+AC_DEFUN([gl_FUNC_GETGROUPS],
+[
+  AC_REQUIRE([AC_TYPE_GETGROUPS])
+  AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+
+  AC_FUNC_GETGROUPS
+  if test $ac_cv_func_getgroups != yes; then
+    HAVE_GETGROUPS=0
+  else
+    if test "$ac_cv_type_getgroups" != gid_t \
+       || { case "$ac_cv_func_getgroups_works" in
+              *yes) false;;
+              *) true;;
+            esac
+          }; then
+      REPLACE_GETGROUPS=1
+      AC_DEFINE([GETGROUPS_ZERO_BUG], [1], [Define this to 1 if
+        getgroups(0,NULL) does not return the number of groups.])
+    else
+      dnl Detect Mac OS X and FreeBSD bug; POSIX requires getgroups(-1,ptr)
+      dnl to fail.
+      AC_CACHE_CHECK([whether getgroups handles negative values],
+        [gl_cv_func_getgroups_works],
+        [AC_RUN_IFELSE([AC_LANG_PROGRAM([AC_INCLUDES_DEFAULT],
+          [[int size = getgroups (0, 0);
+            gid_t *list = malloc (size * sizeof *list);
+            int result = getgroups (-1, list) != -1;
+            free (list);
+            return result;]])],
+          [gl_cv_func_getgroups_works=yes],
+          [gl_cv_func_getgroups_works=no],
+          [case "$host_os" in
+                            # Guess yes on glibc systems.
+             *-gnu* | gnu*) gl_cv_func_getgroups_works="guessing yes" ;;
+                            # Guess yes on musl systems.
+             *-musl*)       gl_cv_func_getgroups_works="guessing yes" ;;
+                            # If we don't know, obey --enable-cross-guesses.
+             *)             gl_cv_func_getgroups_works="$gl_cross_guess_normal" ;;
+           esac
+          ])])
+      case "$gl_cv_func_getgroups_works" in
+        *yes) ;;
+        *) REPLACE_GETGROUPS=1 ;;
+      esac
+    fi
+  fi
+  test -n "$GETGROUPS_LIB" && LIBS="$GETGROUPS_LIB $LIBS"
+])
diff --git a/m4/getline.m4 b/m4/getline.m4
new file mode 100644
index 0000000..0609f1d
--- /dev/null
+++ b/m4/getline.m4
@@ -0,0 +1,109 @@
+# getline.m4 serial 30
+
+dnl Copyright (C) 1998-2003, 2005-2007, 2009-2020 Free Software Foundation,
+dnl Inc.
+dnl
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_PREREQ([2.59])
+
+dnl See if there's a working, system-supplied version of the getline function.
+dnl We can't just do AC_REPLACE_FUNCS([getline]) because some systems
+dnl have a function by that name in -linet that doesn't have anything
+dnl to do with the function we need.
+AC_DEFUN([gl_FUNC_GETLINE],
+[
+  AC_REQUIRE([gl_STDIO_H_DEFAULTS])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+
+  dnl Persuade glibc <stdio.h> to declare getline().
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
+
+  AC_CHECK_DECLS_ONCE([getline])
+
+  gl_getline_needs_run_time_check=no
+  AC_CHECK_FUNC([getline],
+                [dnl Found it in some library.  Verify that it works.
+                 gl_getline_needs_run_time_check=yes],
+                [am_cv_func_working_getline=no])
+  if test $gl_getline_needs_run_time_check = yes; then
+    AC_CACHE_CHECK([for working getline function],
+      [am_cv_func_working_getline],
+      [echo fooNbarN | tr -d '\012' | tr N '\012' > conftest.data
+       AC_RUN_IFELSE([AC_LANG_SOURCE([[
+#    include <stdio.h>
+#    include <stdlib.h>
+#    include <string.h>
+    int main ()
+    {
+      FILE *in = fopen ("./conftest.data", "r");
+      if (!in)
+        return 1;
+      {
+        /* Test result for a NULL buffer and a zero size.
+           Based on a test program from Karl Heuer.  */
+        char *line = NULL;
+        size_t siz = 0;
+        int len = getline (&line, &siz, in);
+        if (!(len == 4 && line && strcmp (line, "foo\n") == 0))
+          { free (line); fclose (in); return 2; }
+        free (line);
+      }
+      {
+        /* Test result for a NULL buffer and a non-zero size.
+           This crashes on FreeBSD 8.0.  */
+        char *line = NULL;
+        size_t siz = (size_t)(~0) / 4;
+        if (getline (&line, &siz, in) == -1)
+          { fclose (in); return 3; }
+        free (line);
+      }
+      fclose (in);
+      return 0;
+    }
+    ]])],
+         [am_cv_func_working_getline=yes],
+         [am_cv_func_working_getline=no],
+         [dnl We're cross compiling.
+          dnl Guess it works on glibc2 systems and musl systems.
+          AC_EGREP_CPP([Lucky GNU user],
+            [
+#include <features.h>
+#ifdef __GNU_LIBRARY__
+ #if (__GLIBC__ >= 2) && !defined __UCLIBC__
+  Lucky GNU user
+ #endif
+#endif
+            ],
+            [am_cv_func_working_getline="guessing yes"],
+            [case "$host_os" in
+               *-musl*) am_cv_func_working_getline="guessing yes" ;;
+               *)       am_cv_func_working_getline="$gl_cross_guess_normal" ;;
+             esac
+            ])
+         ])
+      ])
+  fi
+
+  if test $ac_cv_have_decl_getline = no; then
+    HAVE_DECL_GETLINE=0
+  fi
+
+  case "$am_cv_func_working_getline" in
+    *yes) ;;
+    *)
+      dnl Set REPLACE_GETLINE always: Even if we have not found the broken
+      dnl getline function among $LIBS, it may exist in libinet and the
+      dnl executable may be linked with -linet.
+      REPLACE_GETLINE=1
+      ;;
+  esac
+])
+
+# Prerequisites of lib/getline.c.
+AC_DEFUN([gl_PREREQ_GETLINE],
+[
+  :
+])
diff --git a/m4/getopt.m4 b/m4/getopt.m4
new file mode 100644
index 0000000..595483d
--- /dev/null
+++ b/m4/getopt.m4
@@ -0,0 +1,381 @@
+# getopt.m4 serial 47
+dnl Copyright (C) 2002-2006, 2008-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+# Request a POSIX compliant getopt function.
+AC_DEFUN([gl_FUNC_GETOPT_POSIX],
+[
+  m4_divert_text([DEFAULTS], [gl_getopt_required=POSIX])
+  AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
+  AC_REQUIRE([gl_GETOPT_CHECK_HEADERS])
+  dnl Other modules can request the gnulib implementation of the getopt
+  dnl functions unconditionally, by defining gl_REPLACE_GETOPT_ALWAYS.
+  dnl argp.m4 does this.
+  m4_ifdef([gl_REPLACE_GETOPT_ALWAYS], [
+    REPLACE_GETOPT=1
+  ], [
+    REPLACE_GETOPT=0
+    if test -n "$gl_replace_getopt"; then
+      REPLACE_GETOPT=1
+    fi
+  ])
+  if test $REPLACE_GETOPT = 1; then
+    dnl Arrange for getopt.h to be created.
+    gl_GETOPT_SUBSTITUTE_HEADER
+  fi
+])
+
+# Request a POSIX compliant getopt function with GNU extensions (such as
+# options with optional arguments) and the functions getopt_long,
+# getopt_long_only.
+AC_DEFUN([gl_FUNC_GETOPT_GNU],
+[
+  dnl Set the variable gl_getopt_required, so that all invocations of
+  dnl gl_GETOPT_CHECK_HEADERS in the scope of the current configure file
+  dnl will check for getopt with GNU extensions.
+  dnl This means that if one gnulib-tool invocation requests getopt-posix
+  dnl and another gnulib-tool invocation requests getopt-gnu, it is as if
+  dnl both had requested getopt-gnu.
+  m4_divert_text([INIT_PREPARE], [gl_getopt_required=GNU])
+
+  dnl No need to invoke gl_FUNC_GETOPT_POSIX here; this is automatically
+  dnl done through the module dependency getopt-gnu -> getopt-posix.
+])
+
+# Determine whether to replace the entire getopt facility.
+AC_DEFUN([gl_GETOPT_CHECK_HEADERS],
+[
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_REQUIRE([AC_PROG_AWK]) dnl for awk that supports ENVIRON
+
+  dnl Persuade Solaris <unistd.h> to declare optarg, optind, opterr, optopt.
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
+
+  gl_CHECK_NEXT_HEADERS([getopt.h])
+  if test $ac_cv_header_getopt_h = yes; then
+    HAVE_GETOPT_H=1
+  else
+    HAVE_GETOPT_H=0
+  fi
+  AC_SUBST([HAVE_GETOPT_H])
+
+  gl_replace_getopt=
+
+  dnl Test whether <getopt.h> is available.
+  if test -z "$gl_replace_getopt" && test $gl_getopt_required = GNU; then
+    AC_CHECK_HEADERS([getopt.h], [], [gl_replace_getopt=yes])
+  fi
+
+  dnl Test whether the function getopt_long is available.
+  if test -z "$gl_replace_getopt" && test $gl_getopt_required = GNU; then
+    AC_CHECK_FUNCS([getopt_long_only], [], [gl_replace_getopt=yes])
+  fi
+
+  dnl POSIX 2008 does not specify leading '+' behavior, but see
+  dnl http://austingroupbugs.net/view.php?id=191 for a recommendation on
+  dnl the next version of POSIX.  For now, we only guarantee leading '+'
+  dnl behavior with getopt-gnu.
+  if test -z "$gl_replace_getopt"; then
+    AC_CACHE_CHECK([whether getopt is POSIX compatible],
+      [gl_cv_func_getopt_posix],
+      [
+        dnl Merging these three different test programs into a single one
+        dnl would require a reset mechanism. On BSD systems, it can be done
+        dnl through 'optreset'; on some others (glibc), it can be done by
+        dnl setting 'optind' to 0; on others again (HP-UX, IRIX, OSF/1,
+        dnl Solaris 9, musl libc), there is no such mechanism.
+        if test $cross_compiling = no; then
+          dnl Sanity check. Succeeds everywhere (except on MSVC,
+          dnl which lacks <unistd.h> and getopt() entirely).
+          AC_RUN_IFELSE(
+            [AC_LANG_SOURCE([[
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+
+int
+main ()
+{
+  static char program[] = "program";
+  static char a[] = "-a";
+  static char foo[] = "foo";
+  static char bar[] = "bar";
+  char *argv[] = { program, a, foo, bar, NULL };
+  int c;
+
+  c = getopt (4, argv, "ab");
+  if (!(c == 'a'))
+    return 1;
+  c = getopt (4, argv, "ab");
+  if (!(c == -1))
+    return 2;
+  if (!(optind == 2))
+    return 3;
+  return 0;
+}
+]])],
+            [gl_cv_func_getopt_posix=maybe],
+            [gl_cv_func_getopt_posix=no])
+          if test $gl_cv_func_getopt_posix = maybe; then
+            dnl Sanity check with '+'. Succeeds everywhere (except on MSVC,
+            dnl which lacks <unistd.h> and getopt() entirely).
+            AC_RUN_IFELSE(
+              [AC_LANG_SOURCE([[
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+
+int
+main ()
+{
+  static char program[] = "program";
+  static char donald[] = "donald";
+  static char p[] = "-p";
+  static char billy[] = "billy";
+  static char duck[] = "duck";
+  static char a[] = "-a";
+  static char bar[] = "bar";
+  char *argv[] = { program, donald, p, billy, duck, a, bar, NULL };
+  int c;
+
+  c = getopt (7, argv, "+abp:q:");
+  if (!(c == -1))
+    return 4;
+  if (!(strcmp (argv[0], "program") == 0))
+    return 5;
+  if (!(strcmp (argv[1], "donald") == 0))
+    return 6;
+  if (!(strcmp (argv[2], "-p") == 0))
+    return 7;
+  if (!(strcmp (argv[3], "billy") == 0))
+    return 8;
+  if (!(strcmp (argv[4], "duck") == 0))
+    return 9;
+  if (!(strcmp (argv[5], "-a") == 0))
+    return 10;
+  if (!(strcmp (argv[6], "bar") == 0))
+    return 11;
+  if (!(optind == 1))
+    return 12;
+  return 0;
+}
+]])],
+              [gl_cv_func_getopt_posix=maybe],
+              [gl_cv_func_getopt_posix=no])
+          fi
+          if test $gl_cv_func_getopt_posix = maybe; then
+            dnl Detect Mac OS X 10.5, AIX 7.1, mingw bug.
+            AC_RUN_IFELSE(
+              [AC_LANG_SOURCE([[
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+
+int
+main ()
+{
+  static char program[] = "program";
+  static char ab[] = "-ab";
+  char *argv[3] = { program, ab, NULL };
+  if (getopt (2, argv, "ab:") != 'a')
+    return 13;
+  if (getopt (2, argv, "ab:") != '?')
+    return 14;
+  if (optopt != 'b')
+    return 15;
+  if (optind != 2)
+    return 16;
+  return 0;
+}
+]])],
+              [gl_cv_func_getopt_posix=yes],
+              [gl_cv_func_getopt_posix=no])
+          fi
+        else
+          case "$host_os" in
+            darwin* | aix* | mingw*) gl_cv_func_getopt_posix="guessing no";;
+            *)                       gl_cv_func_getopt_posix="guessing yes";;
+          esac
+        fi
+      ])
+    case "$gl_cv_func_getopt_posix" in
+      *no) gl_replace_getopt=yes ;;
+    esac
+  fi
+
+  if test -z "$gl_replace_getopt" && test $gl_getopt_required = GNU; then
+    AC_CACHE_CHECK([for working GNU getopt function], [gl_cv_func_getopt_gnu],
+      [# Even with POSIXLY_CORRECT, the GNU extension of leading '-' in the
+       # optstring is necessary for programs like m4 that have POSIX-mandated
+       # semantics for supporting options interspersed with files.
+       # Also, since getopt_long is a GNU extension, we require optind=0.
+       # Bash ties 'set -o posix' to a non-exported POSIXLY_CORRECT;
+       # so take care to revert to the correct (non-)export state.
+dnl GNU Coding Standards currently allow awk but not env; besides, env
+dnl is ambiguous with environment values that contain newlines.
+       gl_awk_probe='BEGIN { if ("POSIXLY_CORRECT" in ENVIRON) print "x" }'
+       case ${POSIXLY_CORRECT+x}`$AWK "$gl_awk_probe" </dev/null` in
+         xx) gl_had_POSIXLY_CORRECT=exported ;;
+         x)  gl_had_POSIXLY_CORRECT=yes      ;;
+         *)  gl_had_POSIXLY_CORRECT=         ;;
+       esac
+       POSIXLY_CORRECT=1
+       export POSIXLY_CORRECT
+       AC_RUN_IFELSE(
+        [AC_LANG_PROGRAM([[#include <getopt.h>
+                           #include <stddef.h>
+                           #include <string.h>
+           ]GL_NOCRASH[
+           ]], [[
+             int result = 0;
+
+             nocrash_init();
+
+             /* This code succeeds on glibc 2.8, OpenBSD 4.0, Cygwin, mingw,
+                and fails on Mac OS X 10.5, AIX 5.2, HP-UX 11, IRIX 6.5,
+                OSF/1 5.1, Solaris 10.  */
+             {
+               static char conftest[] = "conftest";
+               static char plus[] = "-+";
+               char *argv[3] = { conftest, plus, NULL };
+               opterr = 0;
+               if (getopt (2, argv, "+a") != '?')
+                 result |= 1;
+             }
+             /* This code succeeds on glibc 2.8, mingw,
+                and fails on Mac OS X 10.5, OpenBSD 4.0, AIX 5.2, HP-UX 11,
+                IRIX 6.5, OSF/1 5.1, Solaris 10, Cygwin 1.5.x.  */
+             {
+               static char program[] = "program";
+               static char p[] = "-p";
+               static char foo[] = "foo";
+               static char bar[] = "bar";
+               char *argv[] = { program, p, foo, bar, NULL };
+
+               optind = 1;
+               if (getopt (4, argv, "p::") != 'p')
+                 result |= 2;
+               else if (optarg != NULL)
+                 result |= 4;
+               else if (getopt (4, argv, "p::") != -1)
+                 result |= 6;
+               else if (optind != 2)
+                 result |= 8;
+             }
+             /* This code succeeds on glibc 2.8 and fails on Cygwin 1.7.0.  */
+             {
+               static char program[] = "program";
+               static char foo[] = "foo";
+               static char p[] = "-p";
+               char *argv[] = { program, foo, p, NULL };
+               optind = 0;
+               if (getopt (3, argv, "-p") != 1)
+                 result |= 16;
+               else if (getopt (3, argv, "-p") != 'p')
+                 result |= 16;
+             }
+             /* This code fails on glibc 2.11.  */
+             {
+               static char program[] = "program";
+               static char b[] = "-b";
+               static char a[] = "-a";
+               char *argv[] = { program, b, a, NULL };
+               optind = opterr = 0;
+               if (getopt (3, argv, "+:a:b") != 'b')
+                 result |= 32;
+               else if (getopt (3, argv, "+:a:b") != ':')
+                 result |= 32;
+             }
+             /* This code dumps core on glibc 2.14.  */
+             {
+               static char program[] = "program";
+               static char w[] = "-W";
+               static char dummy[] = "dummy";
+               char *argv[] = { program, w, dummy, NULL };
+               optind = opterr = 1;
+               if (getopt (3, argv, "W;") != 'W')
+                 result |= 64;
+             }
+             return result;
+           ]])],
+        [gl_cv_func_getopt_gnu=yes],
+        [gl_cv_func_getopt_gnu=no],
+        [dnl Cross compiling.
+         dnl Assume the worst, even on glibc platforms.
+         dnl But obey --enable-cross-guesses.
+         gl_cv_func_getopt_gnu="$gl_cross_guess_normal"
+        ])
+       case $gl_had_POSIXLY_CORRECT in
+         exported) ;;
+         yes) AS_UNSET([POSIXLY_CORRECT]); POSIXLY_CORRECT=1 ;;
+         *) AS_UNSET([POSIXLY_CORRECT]) ;;
+       esac
+      ])
+    if test "$gl_cv_func_getopt_gnu" != yes; then
+      gl_replace_getopt=yes
+    else
+      AC_CACHE_CHECK([for working GNU getopt_long function],
+        [gl_cv_func_getopt_long_gnu],
+        [AC_RUN_IFELSE(
+           [AC_LANG_PROGRAM(
+              [[#include <getopt.h>
+                #include <stddef.h>
+                #include <string.h>
+              ]],
+              [[static const struct option long_options[] =
+                  {
+                    { "xtremely-",no_argument,       NULL, 1003 },
+                    { "xtra",     no_argument,       NULL, 1001 },
+                    { "xtreme",   no_argument,       NULL, 1002 },
+                    { "xtremely", no_argument,       NULL, 1003 },
+                    { NULL,       0,                 NULL, 0 }
+                  };
+                /* This code fails on OpenBSD 5.0.  */
+                {
+                  static char program[] = "program";
+                  static char xtremel[] = "--xtremel";
+                  char *argv[] = { program, xtremel, NULL };
+                  int option_index;
+                  optind = 1; opterr = 0;
+                  if (getopt_long (2, argv, "", long_options, &option_index) != 1003)
+                    return 1;
+                }
+                return 0;
+              ]])],
+           [gl_cv_func_getopt_long_gnu=yes],
+           [gl_cv_func_getopt_long_gnu=no],
+           [dnl Cross compiling. Guess no on OpenBSD, yes otherwise.
+            case "$host_os" in
+              openbsd*) gl_cv_func_getopt_long_gnu="guessing no";;
+              *)        gl_cv_func_getopt_long_gnu="guessing yes";;
+            esac
+           ])
+        ])
+      case "$gl_cv_func_getopt_long_gnu" in
+        *yes) ;;
+        *) gl_replace_getopt=yes ;;
+      esac
+    fi
+  fi
+])
+
+AC_DEFUN([gl_GETOPT_SUBSTITUTE_HEADER],
+[
+  AC_CHECK_HEADERS_ONCE([sys/cdefs.h])
+  if test $ac_cv_header_sys_cdefs_h = yes; then
+    HAVE_SYS_CDEFS_H=1
+  else
+    HAVE_SYS_CDEFS_H=0
+  fi
+  AC_SUBST([HAVE_SYS_CDEFS_H])
+
+  AC_DEFINE([__GETOPT_PREFIX], [[rpl_]],
+    [Define to rpl_ if the getopt replacement functions and variables
+     should be used.])
+  GETOPT_H=getopt.h
+  GETOPT_CDEFS_H=getopt-cdefs.h
+  AC_SUBST([GETOPT_H])
+  AC_SUBST([GETOPT_CDEFS_H])
+])
diff --git a/m4/getpagesize.m4 b/m4/getpagesize.m4
new file mode 100644
index 0000000..8f0f046
--- /dev/null
+++ b/m4/getpagesize.m4
@@ -0,0 +1,49 @@
+# getpagesize.m4 serial 10
+dnl Copyright (C) 2002, 2004-2005, 2007, 2009-2020 Free Software Foundation,
+dnl Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_GETPAGESIZE],
+[
+  AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  gl_CHECK_FUNC_GETPAGESIZE
+  if test $gl_cv_func_getpagesize = no; then
+    HAVE_GETPAGESIZE=0
+    AC_CHECK_HEADERS([OS.h])
+    if test $ac_cv_header_OS_h = yes; then
+      HAVE_OS_H=1
+    fi
+    AC_CHECK_HEADERS([sys/param.h])
+    if test $ac_cv_header_sys_param_h = yes; then
+      HAVE_SYS_PARAM_H=1
+    fi
+  fi
+  case "$host_os" in
+    mingw*)
+      REPLACE_GETPAGESIZE=1
+      ;;
+  esac
+  dnl Also check whether it's declared.
+  dnl mingw has getpagesize() in libgcc.a but doesn't declare it.
+  AC_CHECK_DECL([getpagesize], , [HAVE_DECL_GETPAGESIZE=0])
+])
+
+dnl Tests whether the function getpagesize() exists.
+dnl Sets gl_cv_func_getpagesize.
+AC_DEFUN([gl_CHECK_FUNC_GETPAGESIZE],
+[
+  dnl We can't use AC_CHECK_FUNC here, because getpagesize() is defined as a
+  dnl static inline function when compiling for Android 4.4 or older.
+  AC_CACHE_CHECK([for getpagesize], [gl_cv_func_getpagesize],
+    [AC_LINK_IFELSE(
+       [AC_LANG_PROGRAM(
+          [[#include <unistd.h>]],
+          [[return getpagesize();]])
+       ],
+       [gl_cv_func_getpagesize=yes],
+       [gl_cv_func_getpagesize=no])
+    ])
+])
diff --git a/m4/getpass.m4 b/m4/getpass.m4
new file mode 100644
index 0000000..a2262c4
--- /dev/null
+++ b/m4/getpass.m4
@@ -0,0 +1,106 @@
+# getpass.m4 serial 16
+dnl Copyright (C) 2002-2003, 2005-2006, 2009-2020 Free Software Foundation,
+dnl Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+# Provide a getpass() function if the system doesn't have it.
+AC_DEFUN_ONCE([gl_FUNC_GETPASS],
+[
+  AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
+
+  dnl Persuade Solaris <unistd.h> and <stdlib.h> to declare getpass().
+  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+
+  AC_CHECK_FUNCS_ONCE([getpass])
+  if test $ac_cv_func_getpass = no; then
+    HAVE_GETPASS=0
+  fi
+])
+
+# Provide the GNU getpass() implementation. It supports passwords of
+# arbitrary length (not just 8 bytes as on HP-UX).
+AC_DEFUN([gl_FUNC_GETPASS_GNU],
+[
+  AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
+  AC_REQUIRE([gl_FUNC_GETPASS])
+
+  if test $ac_cv_func_getpass = yes; then
+    AC_CACHE_CHECK([for getpass without length limitations],
+      [gl_cv_func_getpass_good],
+      [AC_EGREP_CPP([Lucky GNU user],
+         [
+#include <features.h>
+#ifdef __GNU_LIBRARY__
+ #if (__GLIBC__ >= 2) && !defined __UCLIBC__
+  Lucky GNU user
+ #endif
+#endif
+         ],
+         [gl_cv_func_getpass_good=yes],
+         [gl_cv_func_getpass_good=no])
+      ])
+    if test $gl_cv_func_getpass_good != yes; then
+      REPLACE_GETPASS=1
+    fi
+  fi
+])
+
+# Prerequisites of lib/getpass.c.
+AC_DEFUN([gl_PREREQ_GETPASS], [
+  AC_CHECK_HEADERS_ONCE([stdio_ext.h termios.h])
+  AC_CHECK_FUNCS_ONCE([__fsetlocking])
+  AC_CHECK_DECLS([__fsetlocking],,,
+    [[#include <stdio.h>
+      #if HAVE_STDIO_EXT_H
+       #include <stdio_ext.h>
+      #endif]])
+  AC_CHECK_DECLS_ONCE([fflush_unlocked])
+  AC_CHECK_DECLS_ONCE([flockfile])
+  AC_CHECK_DECLS_ONCE([fputs_unlocked])
+  AC_CHECK_DECLS_ONCE([funlockfile])
+  AC_CHECK_DECLS_ONCE([putc_unlocked])
+
+  dnl We can't use AC_CHECK_FUNC here, because tcgetattr() is defined as a
+  dnl static inline function when compiling for Android 4.4 or older.
+  AC_CACHE_CHECK([for tcgetattr], [gl_cv_func_tcgetattr],
+    [AC_LINK_IFELSE(
+       [AC_LANG_PROGRAM(
+          [[#include <termios.h>
+            struct termios x;
+          ]],
+          [[return tcgetattr(0,&x);]])
+       ],
+       [gl_cv_func_tcgetattr=yes],
+       [gl_cv_func_tcgetattr=no])
+    ])
+  if test $gl_cv_func_tcgetattr = yes; then
+    HAVE_TCGETATTR=1
+  else
+    HAVE_TCGETATTR=0
+  fi
+  AC_DEFINE_UNQUOTED([HAVE_TCGETATTR], [$HAVE_TCGETATTR],
+    [Define to 1 if the system has the 'tcgetattr' function.])
+
+  dnl We can't use AC_CHECK_FUNC here, because tcsetattr() is defined as a
+  dnl static inline function when compiling for Android 4.4 or older.
+  AC_CACHE_CHECK([for tcsetattr], [gl_cv_func_tcsetattr],
+    [AC_LINK_IFELSE(
+       [AC_LANG_PROGRAM(
+          [[#include <termios.h>
+            struct termios x;
+          ]],
+          [[return tcsetattr(0,0,&x);]])
+       ],
+       [gl_cv_func_tcsetattr=yes],
+       [gl_cv_func_tcsetattr=no])
+    ])
+  if test $gl_cv_func_tcsetattr = yes; then
+    HAVE_TCSETATTR=1
+  else
+    HAVE_TCSETATTR=0
+  fi
+  AC_DEFINE_UNQUOTED([HAVE_TCSETATTR], [$HAVE_TCSETATTR],
+    [Define to 1 if the system has the 'tcsetattr' function.])
+])
diff --git a/m4/getprogname.m4 b/m4/getprogname.m4
new file mode 100644
index 0000000..6baefc9
--- /dev/null
+++ b/m4/getprogname.m4
@@ -0,0 +1,43 @@
+# getprogname.m4 - check for getprogname or replacements for it
+
+# Copyright (C) 2016-2020 Free Software Foundation, Inc.
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+# serial 4
+
+AC_DEFUN([gl_FUNC_GETPROGNAME],
+[
+  AC_CHECK_FUNCS_ONCE([getprogname getexecname])
+  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+  ac_found=0
+  AC_CHECK_DECLS([program_invocation_name], [ac_found=1], [],
+    [#include <errno.h>])
+  AC_CHECK_DECLS([program_invocation_short_name], [ac_found=1], [],
+    [#include <errno.h>])
+  AC_CHECK_DECLS([__argv], [ac_found=1], [], [#include <stdlib.h>])
+
+  # Incur the cost of this test only if none of the above worked.
+  if test $ac_found = 0; then
+    # On OpenBSD 5.1, using the global __progname variable appears to be
+    # the only way to implement getprogname.
+    AC_CACHE_CHECK([whether __progname is defined in default libraries],
+      [gl_cv_var___progname],
+      [
+        gl_cv_var___progname=
+        AC_LINK_IFELSE(
+          [AC_LANG_PROGRAM(
+            [[extern char *__progname;]],
+            [[return *__progname;]]
+          )],
+          [gl_cv_var___progname=yes]
+        )
+      ]
+    )
+    if test "$gl_cv_var___progname" = yes; then
+      AC_DEFINE([HAVE_VAR___PROGNAME], 1,
+        [Define if you have a global __progname variable])
+    fi
+  fi
+])
diff --git a/m4/getrandom.m4 b/m4/getrandom.m4
new file mode 100644
index 0000000..d6da71a
--- /dev/null
+++ b/m4/getrandom.m4
@@ -0,0 +1,68 @@
+# getrandom.m4 serial 8
+dnl Copyright 2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl Written by Paul Eggert.
+
+AC_DEFUN([gl_FUNC_GETRANDOM],
+[
+  AC_REQUIRE([gl_SYS_RANDOM_H_DEFAULTS])
+  AC_CHECK_FUNCS_ONCE([getrandom])
+  if test "$ac_cv_func_getrandom" != yes; then
+    HAVE_GETRANDOM=0
+  else
+    dnl On Solaris 11.4 the return type is 'int', not 'ssize_t'.
+    AC_CACHE_CHECK([whether getrandom is compatible with its GNU+BSD signature],
+      [gl_cv_func_getrandom_ok],
+      [AC_COMPILE_IFELSE(
+         [AC_LANG_PROGRAM(
+            [[/* Additional includes are needed before <sys/random.h> on uClibc
+                 and Mac OS X.  */
+              #include <sys/types.h>
+              #include <stdlib.h>
+              #include <sys/random.h>
+              ssize_t getrandom (void *, size_t, unsigned int);
+            ]],
+            [[]])
+         ],
+         [gl_cv_func_getrandom_ok=yes],
+         [gl_cv_func_getrandom_ok=no])
+      ])
+    if test $gl_cv_func_getrandom_ok = no; then
+      REPLACE_GETRANDOM=1
+    fi
+  fi
+
+  case "$host_os" in
+    mingw*)
+      AC_CHECK_HEADERS([bcrypt.h], [], [],
+        [[#include <windows.h>
+        ]])
+      AC_CACHE_CHECK([whether the bcrypt library is guaranteed to be present],
+        [gl_cv_lib_assume_bcrypt],
+        [AC_COMPILE_IFELSE(
+           [AC_LANG_PROGRAM(
+              [[#include <windows.h>]],
+              [[#if !(_WIN32_WINNT >= _WIN32_WINNT_WIN7)
+                  cannot assume it
+                #endif
+              ]])
+           ],
+           [gl_cv_lib_assume_bcrypt=yes],
+           [gl_cv_lib_assume_bcrypt=no])
+        ])
+      if test $gl_cv_lib_assume_bcrypt = yes; then
+        AC_DEFINE([HAVE_LIB_BCRYPT], [1],
+          [Define to 1 if the bcrypt library is guaranteed to be present.])
+        LIB_GETRANDOM='-lbcrypt'
+      else
+        LIB_GETRANDOM='-ladvapi32'
+      fi
+      ;;
+    *)
+      LIB_GETRANDOM= ;;
+  esac
+  AC_SUBST([LIB_GETRANDOM])
+])
diff --git a/m4/gettext.m4 b/m4/gettext.m4
new file mode 100644
index 0000000..be247bf
--- /dev/null
+++ b/m4/gettext.m4
@@ -0,0 +1,401 @@
+# gettext.m4 serial 66 (gettext-0.18.2)
+dnl Copyright (C) 1995-2014 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+dnl
+dnl This file can can be used in projects which are not available under
+dnl the GNU General Public License or the GNU Library General Public
+dnl License but which still want to provide support for the GNU gettext
+dnl functionality.
+dnl Please note that the actual code of the GNU gettext library is covered
+dnl by the GNU Library General Public License, and the rest of the GNU
+dnl gettext package package is covered by the GNU General Public License.
+dnl They are *not* in the public domain.
+
+dnl Authors:
+dnl   Ulrich Drepper <drepper@cygnus.com>, 1995-2000.
+dnl   Bruno Haible <haible@clisp.cons.org>, 2000-2006, 2008-2010.
+
+dnl Macro to add for using GNU gettext.
+
+dnl Usage: AM_GNU_GETTEXT([INTLSYMBOL], [NEEDSYMBOL], [INTLDIR]).
+dnl INTLSYMBOL can be one of 'external', 'no-libtool', 'use-libtool'. The
+dnl    default (if it is not specified or empty) is 'no-libtool'.
+dnl    INTLSYMBOL should be 'external' for packages with no intl directory,
+dnl    and 'no-libtool' or 'use-libtool' for packages with an intl directory.
+dnl    If INTLSYMBOL is 'use-libtool', then a libtool library
+dnl    $(top_builddir)/intl/libintl.la will be created (shared and/or static,
+dnl    depending on --{enable,disable}-{shared,static} and on the presence of
+dnl    AM-DISABLE-SHARED). If INTLSYMBOL is 'no-libtool', a static library
+dnl    $(top_builddir)/intl/libintl.a will be created.
+dnl If NEEDSYMBOL is specified and is 'need-ngettext', then GNU gettext
+dnl    implementations (in libc or libintl) without the ngettext() function
+dnl    will be ignored.  If NEEDSYMBOL is specified and is
+dnl    'need-formatstring-macros', then GNU gettext implementations that don't
+dnl    support the ISO C 99 <inttypes.h> formatstring macros will be ignored.
+dnl INTLDIR is used to find the intl libraries.  If empty,
+dnl    the value '$(top_builddir)/intl/' is used.
+dnl
+dnl The result of the configuration is one of three cases:
+dnl 1) GNU gettext, as included in the intl subdirectory, will be compiled
+dnl    and used.
+dnl    Catalog format: GNU --> install in $(datadir)
+dnl    Catalog extension: .mo after installation, .gmo in source tree
+dnl 2) GNU gettext has been found in the system's C library.
+dnl    Catalog format: GNU --> install in $(datadir)
+dnl    Catalog extension: .mo after installation, .gmo in source tree
+dnl 3) No internationalization, always use English msgid.
+dnl    Catalog format: none
+dnl    Catalog extension: none
+dnl If INTLSYMBOL is 'external', only cases 2 and 3 can occur.
+dnl The use of .gmo is historical (it was needed to avoid overwriting the
+dnl GNU format catalogs when building on a platform with an X/Open gettext),
+dnl but we keep it in order not to force irrelevant filename changes on the
+dnl maintainers.
+dnl
+AC_DEFUN([AM_GNU_GETTEXT],
+[
+  dnl Argument checking.
+  ifelse([$1], [], , [ifelse([$1], [external], , [ifelse([$1], [no-libtool], , [ifelse([$1], [use-libtool], ,
+    [errprint([ERROR: invalid first argument to AM_GNU_GETTEXT
+])])])])])
+  ifelse(ifelse([$1], [], [old])[]ifelse([$1], [no-libtool], [old]), [old],
+    [AC_DIAGNOSE([obsolete], [Use of AM_GNU_GETTEXT without [external] argument is deprecated.])])
+  ifelse([$2], [], , [ifelse([$2], [need-ngettext], , [ifelse([$2], [need-formatstring-macros], ,
+    [errprint([ERROR: invalid second argument to AM_GNU_GETTEXT
+])])])])
+  define([gt_included_intl],
+    ifelse([$1], [external],
+      ifdef([AM_GNU_GETTEXT_][INTL_SUBDIR], [yes], [no]),
+      [yes]))
+  define([gt_libtool_suffix_prefix], ifelse([$1], [use-libtool], [l], []))
+  gt_NEEDS_INIT
+  AM_GNU_GETTEXT_NEED([$2])
+
+  AC_REQUIRE([AM_PO_SUBDIRS])dnl
+  ifelse(gt_included_intl, yes, [
+    AC_REQUIRE([AM_INTL_SUBDIR])dnl
+  ])
+
+  dnl Prerequisites of AC_LIB_LINKFLAGS_BODY.
+  AC_REQUIRE([AC_LIB_PREPARE_PREFIX])
+  AC_REQUIRE([AC_LIB_RPATH])
+
+  dnl Sometimes libintl requires libiconv, so first search for libiconv.
+  dnl Ideally we would do this search only after the
+  dnl      if test "$USE_NLS" = "yes"; then
+  dnl        if { eval "gt_val=\$$gt_func_gnugettext_libc"; test "$gt_val" != "yes"; }; then
+  dnl tests. But if configure.in invokes AM_ICONV after AM_GNU_GETTEXT
+  dnl the configure script would need to contain the same shell code
+  dnl again, outside any 'if'. There are two solutions:
+  dnl - Invoke AM_ICONV_LINKFLAGS_BODY here, outside any 'if'.
+  dnl - Control the expansions in more detail using AC_PROVIDE_IFELSE.
+  dnl Since AC_PROVIDE_IFELSE is only in autoconf >= 2.52 and not
+  dnl documented, we avoid it.
+  ifelse(gt_included_intl, yes, , [
+    AC_REQUIRE([AM_ICONV_LINKFLAGS_BODY])
+  ])
+
+  dnl Sometimes, on Mac OS X, libintl requires linking with CoreFoundation.
+  gt_INTL_MACOSX
+
+  dnl Set USE_NLS.
+  AC_REQUIRE([AM_NLS])
+
+  ifelse(gt_included_intl, yes, [
+    BUILD_INCLUDED_LIBINTL=no
+    USE_INCLUDED_LIBINTL=no
+  ])
+  LIBINTL=
+  LTLIBINTL=
+  POSUB=
+
+  dnl Add a version number to the cache macros.
+  case " $gt_needs " in
+    *" need-formatstring-macros "*) gt_api_version=3 ;;
+    *" need-ngettext "*) gt_api_version=2 ;;
+    *) gt_api_version=1 ;;
+  esac
+  gt_func_gnugettext_libc="gt_cv_func_gnugettext${gt_api_version}_libc"
+  gt_func_gnugettext_libintl="gt_cv_func_gnugettext${gt_api_version}_libintl"
+
+  dnl If we use NLS figure out what method
+  if test "$USE_NLS" = "yes"; then
+    gt_use_preinstalled_gnugettext=no
+    ifelse(gt_included_intl, yes, [
+      AC_MSG_CHECKING([whether included gettext is requested])
+      AC_ARG_WITH([included-gettext],
+        [  --with-included-gettext use the GNU gettext library included here],
+        nls_cv_force_use_gnu_gettext=$withval,
+        nls_cv_force_use_gnu_gettext=no)
+      AC_MSG_RESULT([$nls_cv_force_use_gnu_gettext])
+
+      nls_cv_use_gnu_gettext="$nls_cv_force_use_gnu_gettext"
+      if test "$nls_cv_force_use_gnu_gettext" != "yes"; then
+    ])
+        dnl User does not insist on using GNU NLS library.  Figure out what
+        dnl to use.  If GNU gettext is available we use this.  Else we have
+        dnl to fall back to GNU NLS library.
+
+        if test $gt_api_version -ge 3; then
+          gt_revision_test_code='
+#ifndef __GNU_GETTEXT_SUPPORTED_REVISION
+#define __GNU_GETTEXT_SUPPORTED_REVISION(major) ((major) == 0 ? 0 : -1)
+#endif
+changequote(,)dnl
+typedef int array [2 * (__GNU_GETTEXT_SUPPORTED_REVISION(0) >= 1) - 1];
+changequote([,])dnl
+'
+        else
+          gt_revision_test_code=
+        fi
+        if test $gt_api_version -ge 2; then
+          gt_expression_test_code=' + * ngettext ("", "", 0)'
+        else
+          gt_expression_test_code=
+        fi
+
+        AC_CACHE_CHECK([for GNU gettext in libc], [$gt_func_gnugettext_libc],
+         [AC_LINK_IFELSE(
+            [AC_LANG_PROGRAM(
+               [[
+#include <libintl.h>
+$gt_revision_test_code
+extern int _nl_msg_cat_cntr;
+extern int *_nl_domain_bindings;
+               ]],
+               [[
+bindtextdomain ("", "");
+return * gettext ("")$gt_expression_test_code + _nl_msg_cat_cntr + *_nl_domain_bindings
+               ]])],
+            [eval "$gt_func_gnugettext_libc=yes"],
+            [eval "$gt_func_gnugettext_libc=no"])])
+
+        if { eval "gt_val=\$$gt_func_gnugettext_libc"; test "$gt_val" != "yes"; }; then
+          dnl Sometimes libintl requires libiconv, so first search for libiconv.
+          ifelse(gt_included_intl, yes, , [
+            AM_ICONV_LINK
+          ])
+          dnl Search for libintl and define LIBINTL, LTLIBINTL and INCINTL
+          dnl accordingly. Don't use AC_LIB_LINKFLAGS_BODY([intl],[iconv])
+          dnl because that would add "-liconv" to LIBINTL and LTLIBINTL
+          dnl even if libiconv doesn't exist.
+          AC_LIB_LINKFLAGS_BODY([intl])
+          AC_CACHE_CHECK([for GNU gettext in libintl],
+            [$gt_func_gnugettext_libintl],
+           [gt_save_CPPFLAGS="$CPPFLAGS"
+            CPPFLAGS="$CPPFLAGS $INCINTL"
+            gt_save_LIBS="$LIBS"
+            LIBS="$LIBS $LIBINTL"
+            dnl Now see whether libintl exists and does not depend on libiconv.
+            AC_LINK_IFELSE(
+              [AC_LANG_PROGRAM(
+                 [[
+#include <libintl.h>
+$gt_revision_test_code
+extern int _nl_msg_cat_cntr;
+extern
+#ifdef __cplusplus
+"C"
+#endif
+const char *_nl_expand_alias (const char *);
+                 ]],
+                 [[
+bindtextdomain ("", "");
+return * gettext ("")$gt_expression_test_code + _nl_msg_cat_cntr + *_nl_expand_alias ("")
+                 ]])],
+              [eval "$gt_func_gnugettext_libintl=yes"],
+              [eval "$gt_func_gnugettext_libintl=no"])
+            dnl Now see whether libintl exists and depends on libiconv.
+            if { eval "gt_val=\$$gt_func_gnugettext_libintl"; test "$gt_val" != yes; } && test -n "$LIBICONV"; then
+              LIBS="$LIBS $LIBICONV"
+              AC_LINK_IFELSE(
+                [AC_LANG_PROGRAM(
+                   [[
+#include <libintl.h>
+$gt_revision_test_code
+extern int _nl_msg_cat_cntr;
+extern
+#ifdef __cplusplus
+"C"
+#endif
+const char *_nl_expand_alias (const char *);
+                   ]],
+                   [[
+bindtextdomain ("", "");
+return * gettext ("")$gt_expression_test_code + _nl_msg_cat_cntr + *_nl_expand_alias ("")
+                   ]])],
+                [LIBINTL="$LIBINTL $LIBICONV"
+                 LTLIBINTL="$LTLIBINTL $LTLIBICONV"
+                 eval "$gt_func_gnugettext_libintl=yes"
+                ])
+            fi
+            CPPFLAGS="$gt_save_CPPFLAGS"
+            LIBS="$gt_save_LIBS"])
+        fi
+
+        dnl If an already present or preinstalled GNU gettext() is found,
+        dnl use it.  But if this macro is used in GNU gettext, and GNU
+        dnl gettext is already preinstalled in libintl, we update this
+        dnl libintl.  (Cf. the install rule in intl/Makefile.in.)
+        if { eval "gt_val=\$$gt_func_gnugettext_libc"; test "$gt_val" = "yes"; } \
+           || { { eval "gt_val=\$$gt_func_gnugettext_libintl"; test "$gt_val" = "yes"; } \
+                && test "$PACKAGE" != gettext-runtime \
+                && test "$PACKAGE" != gettext-tools; }; then
+          gt_use_preinstalled_gnugettext=yes
+        else
+          dnl Reset the values set by searching for libintl.
+          LIBINTL=
+          LTLIBINTL=
+          INCINTL=
+        fi
+
+    ifelse(gt_included_intl, yes, [
+        if test "$gt_use_preinstalled_gnugettext" != "yes"; then
+          dnl GNU gettext is not found in the C library.
+          dnl Fall back on included GNU gettext library.
+          nls_cv_use_gnu_gettext=yes
+        fi
+      fi
+
+      if test "$nls_cv_use_gnu_gettext" = "yes"; then
+        dnl Mark actions used to generate GNU NLS library.
+        BUILD_INCLUDED_LIBINTL=yes
+        USE_INCLUDED_LIBINTL=yes
+        LIBINTL="ifelse([$3],[],\${top_builddir}/intl,[$3])/libintl.[]gt_libtool_suffix_prefix[]a $LIBICONV $LIBTHREAD"
+        LTLIBINTL="ifelse([$3],[],\${top_builddir}/intl,[$3])/libintl.[]gt_libtool_suffix_prefix[]a $LTLIBICONV $LTLIBTHREAD"
+        LIBS=`echo " $LIBS " | sed -e 's/ -lintl / /' -e 's/^ //' -e 's/ $//'`
+      fi
+
+      CATOBJEXT=
+      if test "$gt_use_preinstalled_gnugettext" = "yes" \
+         || test "$nls_cv_use_gnu_gettext" = "yes"; then
+        dnl Mark actions to use GNU gettext tools.
+        CATOBJEXT=.gmo
+      fi
+    ])
+
+    if test -n "$INTL_MACOSX_LIBS"; then
+      if test "$gt_use_preinstalled_gnugettext" = "yes" \
+         || test "$nls_cv_use_gnu_gettext" = "yes"; then
+        dnl Some extra flags are needed during linking.
+        LIBINTL="$LIBINTL $INTL_MACOSX_LIBS"
+        LTLIBINTL="$LTLIBINTL $INTL_MACOSX_LIBS"
+      fi
+    fi
+
+    if test "$gt_use_preinstalled_gnugettext" = "yes" \
+       || test "$nls_cv_use_gnu_gettext" = "yes"; then
+      AC_DEFINE([ENABLE_NLS], [1],
+        [Define to 1 if translation of program messages to the user's native language
+   is requested.])
+    else
+      USE_NLS=no
+    fi
+  fi
+
+  AC_MSG_CHECKING([whether to use NLS])
+  AC_MSG_RESULT([$USE_NLS])
+  if test "$USE_NLS" = "yes"; then
+    AC_MSG_CHECKING([where the gettext function comes from])
+    if test "$gt_use_preinstalled_gnugettext" = "yes"; then
+      if { eval "gt_val=\$$gt_func_gnugettext_libintl"; test "$gt_val" = "yes"; }; then
+        gt_source="external libintl"
+      else
+        gt_source="libc"
+      fi
+    else
+      gt_source="included intl directory"
+    fi
+    AC_MSG_RESULT([$gt_source])
+  fi
+
+  if test "$USE_NLS" = "yes"; then
+
+    if test "$gt_use_preinstalled_gnugettext" = "yes"; then
+      if { eval "gt_val=\$$gt_func_gnugettext_libintl"; test "$gt_val" = "yes"; }; then
+        AC_MSG_CHECKING([how to link with libintl])
+        AC_MSG_RESULT([$LIBINTL])
+        AC_LIB_APPENDTOVAR([CPPFLAGS], [$INCINTL])
+      fi
+
+      dnl For backward compatibility. Some packages may be using this.
+      AC_DEFINE([HAVE_GETTEXT], [1],
+       [Define if the GNU gettext() function is already present or preinstalled.])
+      AC_DEFINE([HAVE_DCGETTEXT], [1],
+       [Define if the GNU dcgettext() function is already present or preinstalled.])
+    fi
+
+    dnl We need to process the po/ directory.
+    POSUB=po
+  fi
+
+  ifelse(gt_included_intl, yes, [
+    dnl If this is used in GNU gettext we have to set BUILD_INCLUDED_LIBINTL
+    dnl to 'yes' because some of the testsuite requires it.
+    if test "$PACKAGE" = gettext-runtime || test "$PACKAGE" = gettext-tools; then
+      BUILD_INCLUDED_LIBINTL=yes
+    fi
+
+    dnl Make all variables we use known to autoconf.
+    AC_SUBST([BUILD_INCLUDED_LIBINTL])
+    AC_SUBST([USE_INCLUDED_LIBINTL])
+    AC_SUBST([CATOBJEXT])
+
+    dnl For backward compatibility. Some configure.ins may be using this.
+    nls_cv_header_intl=
+    nls_cv_header_libgt=
+
+    dnl For backward compatibility. Some Makefiles may be using this.
+    DATADIRNAME=share
+    AC_SUBST([DATADIRNAME])
+
+    dnl For backward compatibility. Some Makefiles may be using this.
+    INSTOBJEXT=.mo
+    AC_SUBST([INSTOBJEXT])
+
+    dnl For backward compatibility. Some Makefiles may be using this.
+    GENCAT=gencat
+    AC_SUBST([GENCAT])
+
+    dnl For backward compatibility. Some Makefiles may be using this.
+    INTLOBJS=
+    if test "$USE_INCLUDED_LIBINTL" = yes; then
+      INTLOBJS="\$(GETTOBJS)"
+    fi
+    AC_SUBST([INTLOBJS])
+
+    dnl Enable libtool support if the surrounding package wishes it.
+    INTL_LIBTOOL_SUFFIX_PREFIX=gt_libtool_suffix_prefix
+    AC_SUBST([INTL_LIBTOOL_SUFFIX_PREFIX])
+  ])
+
+  dnl For backward compatibility. Some Makefiles may be using this.
+  INTLLIBS="$LIBINTL"
+  AC_SUBST([INTLLIBS])
+
+  dnl Make all documented variables known to autoconf.
+  AC_SUBST([LIBINTL])
+  AC_SUBST([LTLIBINTL])
+  AC_SUBST([POSUB])
+])
+
+
+dnl gt_NEEDS_INIT ensures that the gt_needs variable is initialized.
+m4_define([gt_NEEDS_INIT],
+[
+  m4_divert_text([DEFAULTS], [gt_needs=])
+  m4_define([gt_NEEDS_INIT], [])
+])
+
+
+dnl Usage: AM_GNU_GETTEXT_NEED([NEEDSYMBOL])
+AC_DEFUN([AM_GNU_GETTEXT_NEED],
+[
+  m4_divert_text([INIT_PREPARE], [gt_needs="$gt_needs $1"])
+])
+
+
+dnl Usage: AM_GNU_GETTEXT_VERSION([gettext-version])
+AC_DEFUN([AM_GNU_GETTEXT_VERSION], [])
diff --git a/m4/gettime.m4 b/m4/gettime.m4
new file mode 100644
index 0000000..e65455a
--- /dev/null
+++ b/m4/gettime.m4
@@ -0,0 +1,13 @@
+# gettime.m4 serial 9
+dnl Copyright (C) 2002, 2004-2006, 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_GETTIME],
+[
+  dnl Prerequisites of lib/gettime.c.
+  AC_REQUIRE([gl_CLOCK_TIME])
+  AC_REQUIRE([gl_TIMESPEC])
+  AC_CHECK_FUNCS_ONCE([gettimeofday])
+])
diff --git a/m4/gettimeofday.m4 b/m4/gettimeofday.m4
new file mode 100644
index 0000000..578ed49
--- /dev/null
+++ b/m4/gettimeofday.m4
@@ -0,0 +1,69 @@
+# serial 28
+
+# Copyright (C) 2001-2003, 2005, 2007, 2009-2020 Free Software Foundation, Inc.
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+dnl From Jim Meyering.
+
+AC_DEFUN([gl_FUNC_GETTIMEOFDAY],
+[
+  AC_REQUIRE([gl_HEADER_SYS_TIME_H_DEFAULTS])
+  AC_REQUIRE([AC_C_RESTRICT])
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  AC_REQUIRE([gl_HEADER_SYS_TIME_H])
+  AC_CHECK_FUNCS_ONCE([gettimeofday])
+
+  gl_gettimeofday_timezone=void
+  if test $ac_cv_func_gettimeofday != yes; then
+    HAVE_GETTIMEOFDAY=0
+  else
+    AC_CACHE_CHECK([for gettimeofday with POSIX signature],
+      [gl_cv_func_gettimeofday_posix_signature],
+      [AC_COMPILE_IFELSE(
+         [AC_LANG_PROGRAM(
+            [[#include <sys/time.h>
+              struct timeval c;
+              int gettimeofday (struct timeval *restrict, void *restrict);
+            ]],
+            [[/* glibc uses struct timezone * rather than the POSIX void *
+                 if _GNU_SOURCE is defined.  However, since the only portable
+                 use of gettimeofday uses NULL as the second parameter, and
+                 since the glibc definition is actually more typesafe, it is
+                 not worth wrapping this to get a compliant signature.  */
+              int (*f) (struct timeval *restrict, void *restrict)
+                = gettimeofday;
+              int x = f (&c, 0);
+              return !(x | c.tv_sec | c.tv_usec);
+            ]])],
+          [gl_cv_func_gettimeofday_posix_signature=yes],
+          [AC_COMPILE_IFELSE(
+            [AC_LANG_PROGRAM(
+              [[#include <sys/time.h>
+int gettimeofday (struct timeval *restrict, struct timezone *restrict);
+              ]])],
+            [gl_cv_func_gettimeofday_posix_signature=almost],
+            [gl_cv_func_gettimeofday_posix_signature=no])])])
+    if test $gl_cv_func_gettimeofday_posix_signature = almost; then
+      gl_gettimeofday_timezone='struct timezone'
+    elif test $gl_cv_func_gettimeofday_posix_signature != yes; then
+      REPLACE_GETTIMEOFDAY=1
+    fi
+    dnl If we override 'struct timeval', we also have to override gettimeofday.
+    if test $REPLACE_STRUCT_TIMEVAL = 1; then
+      REPLACE_GETTIMEOFDAY=1
+    fi
+    dnl On mingw, the original gettimeofday has only a precision of 15.6
+    dnl milliseconds. So override it.
+    case "$host_os" in
+      mingw*) REPLACE_GETTIMEOFDAY=1 ;;
+    esac
+  fi
+  AC_DEFINE_UNQUOTED([GETTIMEOFDAY_TIMEZONE], [$gl_gettimeofday_timezone],
+    [Define this to 'void' or 'struct timezone' to match the system's
+     declaration of the second argument to gettimeofday.])
+])
+
+# Prerequisites of lib/gettimeofday.c.
+AC_DEFUN([gl_PREREQ_GETTIMEOFDAY], [:])
diff --git a/m4/gl-openssl.m4 b/m4/gl-openssl.m4
new file mode 100644
index 0000000..e950904
--- /dev/null
+++ b/m4/gl-openssl.m4
@@ -0,0 +1,66 @@
+# gl-openssl.m4 serial 5
+dnl Copyright (C) 2013-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_SET_CRYPTO_CHECK_DEFAULT],
+[
+  m4_define([gl_CRYPTO_CHECK_DEFAULT], [$1])
+])
+gl_SET_CRYPTO_CHECK_DEFAULT([no])
+
+AC_DEFUN([gl_CRYPTO_CHECK],
+[
+  dnl gnulib users set this before gl_INIT with gl_SET_CRYPTO_CHECK_DEFAULT()
+  m4_divert_once([DEFAULTS], [with_openssl_default='gl_CRYPTO_CHECK_DEFAULT'])
+
+  dnl Only clear once, so crypto routines can be checked for individually
+  m4_divert_once([DEFAULTS], [LIB_CRYPTO=])
+
+  AC_ARG_WITH([openssl],
+    [AS_HELP_STRING([--with-openssl],
+      [use libcrypto hash routines. Valid ARGs are:
+       'yes', 'no',
+       'auto' => use if any version available,
+       'auto-gpl-compat' => use if gpl compatible version available,
+       'optional' => use if available and warn if not available;
+       default is ']gl_CRYPTO_CHECK_DEFAULT['.
+       Note also --with-linux-crypto, which will enable
+       use of kernel crypto routines, which have precedence])],
+    [],
+    [with_openssl=$with_openssl_default])
+
+  AC_SUBST([LIB_CRYPTO])
+  if test "x$with_openssl" != xno; then
+    if test "x$with_openssl" = xauto-gpl-compat; then
+      AC_CACHE_CHECK([whether openssl is GPL compatible],
+                     [gl_cv_openssl_gpl_compat],
+        [AC_COMPILE_IFELSE(
+           [AC_LANG_PROGRAM([[
+                #include <openssl/opensslv.h>
+                #if OPENSSL_VERSION_MAJOR < 3
+                  #error "openssl >= version 3 not found"
+                #endif
+              ]])],
+           [gl_cv_openssl_gpl_compat=yes],
+           [gl_cv_openssl_gpl_compat=no])])
+    fi
+    if test "x$with_openssl" != xauto-gpl-compat ||
+       test "x$gl_cv_openssl_gpl_compat" = xyes; then
+      AC_CHECK_LIB([crypto], [$1],
+        [AC_CHECK_HEADERS(
+           m4_if([$1], [MD5], [openssl/md5.h], [openssl/sha.h]),
+           [LIB_CRYPTO=-lcrypto
+            AC_DEFINE([HAVE_OPENSSL_$1], [1],
+              [Define to 1 if libcrypto is used for $1.])])])
+    fi
+    if test "x$LIB_CRYPTO" = x; then
+      if test "x$with_openssl" = xyes; then
+        AC_MSG_ERROR([openssl development library not found for $1])
+      elif test "x$with_openssl" = xoptional; then
+        AC_MSG_WARN([openssl development library not found for $1])
+      fi
+    fi
+  fi
+])
diff --git a/m4/gnulib-common.m4 b/m4/gnulib-common.m4
new file mode 100644
index 0000000..2c0ae9b
--- /dev/null
+++ b/m4/gnulib-common.m4
@@ -0,0 +1,724 @@
+# gnulib-common.m4 serial 63
+dnl Copyright (C) 2007-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_PREREQ([2.62])
+
+# gl_COMMON
+# is expanded unconditionally through gnulib-tool magic.
+AC_DEFUN([gl_COMMON], [
+  dnl Use AC_REQUIRE here, so that the code is expanded once only.
+  AC_REQUIRE([gl_00GNULIB])
+  AC_REQUIRE([gl_COMMON_BODY])
+  AC_REQUIRE([gl_ZZGNULIB])
+])
+AC_DEFUN([gl_COMMON_BODY], [
+  AH_VERBATIM([_GL_GNUC_PREREQ],
+[/* True if the compiler says it groks GNU C version MAJOR.MINOR.  */
+#if defined __GNUC__ && defined __GNUC_MINOR__
+# define _GL_GNUC_PREREQ(major, minor) \
+    ((major) < __GNUC__ + ((minor) <= __GNUC_MINOR__))
+#else
+# define _GL_GNUC_PREREQ(major, minor) 0
+#endif
+])
+  AH_VERBATIM([_Noreturn],
+[/* The _Noreturn keyword of C11.  */
+#ifndef _Noreturn
+# if (defined __cplusplus \
+      && ((201103 <= __cplusplus && !(__GNUC__ == 4 && __GNUC_MINOR__ == 7)) \
+          || (defined _MSC_VER && 1900 <= _MSC_VER)) \
+      && 0)
+    /* [[noreturn]] is not practically usable, because with it the syntax
+         extern _Noreturn void func (...);
+       would not be valid; such a declaration would only be valid with 'extern'
+       and '_Noreturn' swapped, or without the 'extern' keyword.  However, some
+       AIX system header files and several gnulib header files use precisely
+       this syntax with 'extern'.  */
+#  define _Noreturn [[noreturn]]
+# elif ((!defined __cplusplus || defined __clang__) \
+        && (201112 <= (defined __STDC_VERSION__ ? __STDC_VERSION__ : 0)  \
+            || _GL_GNUC_PREREQ (4, 7) \
+            || (defined __apple_build_version__ \
+                ? 6000000 <= __apple_build_version__ \
+                : 3 < __clang_major__ + (5 <= __clang_minor__))))
+   /* _Noreturn works as-is.  */
+# elif _GL_GNUC_PREREQ (2, 8) || defined __clang__ || 0x5110 <= __SUNPRO_C
+#  define _Noreturn __attribute__ ((__noreturn__))
+# elif 1200 <= (defined _MSC_VER ? _MSC_VER : 0)
+#  define _Noreturn __declspec (noreturn)
+# else
+#  define _Noreturn
+# endif
+#endif
+])
+  AH_VERBATIM([isoc99_inline],
+[/* Work around a bug in Apple GCC 4.0.1 build 5465: In C99 mode, it supports
+   the ISO C 99 semantics of 'extern inline' (unlike the GNU C semantics of
+   earlier versions), but does not display it by setting __GNUC_STDC_INLINE__.
+   __APPLE__ && __MACH__ test for Mac OS X.
+   __APPLE_CC__ tests for the Apple compiler and its version.
+   __STDC_VERSION__ tests for the C99 mode.  */
+#if defined __APPLE__ && defined __MACH__ && __APPLE_CC__ >= 5465 && !defined __cplusplus && __STDC_VERSION__ >= 199901L && !defined __GNUC_STDC_INLINE__
+# define __GNUC_STDC_INLINE__ 1
+#endif])
+  AH_VERBATIM([attribute],
+[/* Attributes.  */
+#ifdef __has_attribute
+# define _GL_HAS_ATTRIBUTE(attr) __has_attribute (__##attr##__)
+#else
+# define _GL_HAS_ATTRIBUTE(attr) _GL_ATTR_##attr
+# define _GL_ATTR_alloc_size _GL_GNUC_PREREQ (4, 3)
+# define _GL_ATTR_always_inline _GL_GNUC_PREREQ (3, 2)
+# define _GL_ATTR_artificial _GL_GNUC_PREREQ (4, 3)
+# define _GL_ATTR_cold _GL_GNUC_PREREQ (4, 3)
+# define _GL_ATTR_const _GL_GNUC_PREREQ (2, 95)
+# define _GL_ATTR_deprecated _GL_GNUC_PREREQ (3, 1)
+# define _GL_ATTR_diagnose_if 0
+# define _GL_ATTR_error _GL_GNUC_PREREQ (4, 3)
+# define _GL_ATTR_externally_visible _GL_GNUC_PREREQ (4, 1)
+# define _GL_ATTR_fallthrough _GL_GNUC_PREREQ (7, 0)
+# define _GL_ATTR_format _GL_GNUC_PREREQ (2, 7)
+# define _GL_ATTR_leaf _GL_GNUC_PREREQ (4, 6)
+# ifdef _ICC
+#  define _GL_ATTR_may_alias 0
+# else
+#  define _GL_ATTR_may_alias _GL_GNUC_PREREQ (3, 3)
+# endif
+# define _GL_ATTR_malloc _GL_GNUC_PREREQ (3, 0)
+# define _GL_ATTR_noinline _GL_GNUC_PREREQ (3, 1)
+# define _GL_ATTR_nonnull _GL_GNUC_PREREQ (3, 3)
+# define _GL_ATTR_nonstring _GL_GNUC_PREREQ (8, 0)
+# define _GL_ATTR_nothrow _GL_GNUC_PREREQ (3, 3)
+# define _GL_ATTR_packed _GL_GNUC_PREREQ (2, 7)
+# define _GL_ATTR_pure _GL_GNUC_PREREQ (2, 96)
+# define _GL_ATTR_returns_nonnull _GL_GNUC_PREREQ (4, 9)
+# define _GL_ATTR_sentinel _GL_GNUC_PREREQ (4, 0)
+# define _GL_ATTR_unused _GL_GNUC_PREREQ (2, 7)
+# define _GL_ATTR_warn_unused_result _GL_GNUC_PREREQ (3, 4)
+#endif
+
+]dnl There is no _GL_ATTRIBUTE_ALIGNED; use stdalign's _Alignas instead.
+[
+#if _GL_HAS_ATTRIBUTE (alloc_size)
+# define _GL_ATTRIBUTE_ALLOC_SIZE(args) __attribute__ ((__alloc_size__ args))
+#else
+# define _GL_ATTRIBUTE_ALLOC_SIZE(args)
+#endif
+
+#if _GL_HAS_ATTRIBUTE (always_inline)
+# define _GL_ATTRIBUTE_ALWAYS_INLINE __attribute__ ((__always_inline__))
+#else
+# define _GL_ATTRIBUTE_ALWAYS_INLINE
+#endif
+
+#if _GL_HAS_ATTRIBUTE (artificial)
+# define _GL_ATTRIBUTE_ARTIFICIAL __attribute__ ((__artificial__))
+#else
+# define _GL_ATTRIBUTE_ARTIFICIAL
+#endif
+
+/* Avoid __attribute__ ((cold)) on MinGW; see thread starting at
+   <https://lists.gnu.org/r/emacs-devel/2019-04/msg01152.html>.
+   Also, Oracle Studio 12.6 requires 'cold' not '__cold__'.  */
+#if _GL_HAS_ATTRIBUTE (cold) && !defined __MINGW32__
+# ifndef __SUNPRO_C
+#  define _GL_ATTRIBUTE_COLD __attribute__ ((__cold__))
+# else
+#  define _GL_ATTRIBUTE_COLD __attribute__ ((cold))
+# endif
+#else
+# define _GL_ATTRIBUTE_COLD
+#endif
+
+#if _GL_HAS_ATTRIBUTE (const)
+# define _GL_ATTRIBUTE_CONST __attribute__ ((__const__))
+#else
+# define _GL_ATTRIBUTE_CONST
+#endif
+
+#if 201710L < __STDC_VERSION__
+# define _GL_ATTRIBUTE_DEPRECATED [[__deprecated__]]
+#elif _GL_HAS_ATTRIBUTE (deprecated)
+# define _GL_ATTRIBUTE_DEPRECATED __attribute__ ((__deprecated__))
+#else
+# define _GL_ATTRIBUTE_DEPRECATED
+#endif
+
+#if _GL_HAS_ATTRIBUTE (error)
+# define _GL_ATTRIBUTE_ERROR(msg) __attribute__ ((__error__ (msg)))
+# define _GL_ATTRIBUTE_WARNING(msg) __attribute__ ((__warning__ (msg)))
+#elif _GL_HAS_ATTRIBUTE (diagnose_if)
+# define _GL_ATTRIBUTE_ERROR(msg) __attribute__ ((__diagnose_if__ (1, msg, "error")))
+# define _GL_ATTRIBUTE_WARNING(msg) __attribute__ ((__diagnose_if__ (1, msg, "warning")))
+#else
+# define _GL_ATTRIBUTE_ERROR(msg)
+# define _GL_ATTRIBUTE_WARNING(msg)
+#endif
+
+#if _GL_HAS_ATTRIBUTE (externally_visible)
+# define _GL_ATTRIBUTE_EXTERNALLY_VISIBLE __attribute__ ((externally_visible))
+#else
+# define _GL_ATTRIBUTE_EXTERNALLY_VISIBLE
+#endif
+
+/* FALLTHROUGH is special, because it always expands to something.  */
+#if 201710L < __STDC_VERSION__
+# define _GL_ATTRIBUTE_FALLTHROUGH [[__fallthrough__]]
+#elif _GL_HAS_ATTRIBUTE (fallthrough)
+# define _GL_ATTRIBUTE_FALLTHROUGH __attribute__ ((__fallthrough__))
+#else
+# define _GL_ATTRIBUTE_FALLTHROUGH ((void) 0)
+#endif
+
+#if _GL_HAS_ATTRIBUTE (format)
+# define _GL_ATTRIBUTE_FORMAT(spec) __attribute__ ((__format__ spec))
+#else
+# define _GL_ATTRIBUTE_FORMAT(spec)
+#endif
+
+#if _GL_HAS_ATTRIBUTE (leaf)
+# define _GL_ATTRIBUTE_LEAF __attribute__ ((__leaf__))
+#else
+# define _GL_ATTRIBUTE_LEAF
+#endif
+
+/* Oracle Studio 12.6 mishandles may_alias despite __has_attribute OK.  */
+#if _GL_HAS_ATTRIBUTE (may_alias) && !defined __SUNPRO_C
+# define _GL_ATTRIBUTE_MAY_ALIAS __attribute__ ((__may_alias__))
+#else
+# define _GL_ATTRIBUTE_MAY_ALIAS
+#endif
+
+#if 201710L < __STDC_VERSION__
+# define _GL_ATTRIBUTE_MAYBE_UNUSED [[__maybe_unused__]]
+#elif _GL_HAS_ATTRIBUTE (unused)
+# define _GL_ATTRIBUTE_MAYBE_UNUSED __attribute__ ((__unused__))
+#else
+# define _GL_ATTRIBUTE_MAYBE_UNUSED
+#endif
+/* Earlier spellings of this macro.  */
+#define _GL_UNUSED _GL_ATTRIBUTE_MAYBE_UNUSED
+#define _UNUSED_PARAMETER_ _GL_ATTRIBUTE_MAYBE_UNUSED
+
+#if _GL_HAS_ATTRIBUTE (malloc)
+# define _GL_ATTRIBUTE_MALLOC __attribute__ ((__malloc__))
+#else
+# define _GL_ATTRIBUTE_MALLOC
+#endif
+
+#if 201710L < __STDC_VERSION__
+# define _GL_ATTRIBUTE_NODISCARD [[__nodiscard__]]
+#elif _GL_HAS_ATTRIBUTE (warn_unused_result)
+# define _GL_ATTRIBUTE_NODISCARD __attribute__ ((__warn_unused_result__))
+#else
+# define _GL_ATTRIBUTE_NODISCARD
+#endif
+
+#if _GL_HAS_ATTRIBUTE (noinline)
+# define _GL_ATTRIBUTE_NOINLINE __attribute__ ((__noinline__))
+#else
+# define _GL_ATTRIBUTE_NOINLINE
+#endif
+
+#if _GL_HAS_ATTRIBUTE (nonnull)
+# define _GL_ATTRIBUTE_NONNULL(args) __attribute__ ((__nonnull__ args))
+#else
+# define _GL_ATTRIBUTE_NONNULL(args)
+#endif
+
+#if _GL_HAS_ATTRIBUTE (nonstring)
+# define _GL_ATTRIBUTE_NONSTRING __attribute__ ((__nonstring__))
+#else
+# define _GL_ATTRIBUTE_NONSTRING
+#endif
+
+/* There is no _GL_ATTRIBUTE_NORETURN; use _Noreturn instead.  */
+
+#if _GL_HAS_ATTRIBUTE (nothrow) && !defined __cplusplus
+# define _GL_ATTRIBUTE_NOTHROW __attribute__ ((__nothrow__))
+#else
+# define _GL_ATTRIBUTE_NOTHROW
+#endif
+
+#if _GL_HAS_ATTRIBUTE (packed)
+# define _GL_ATTRIBUTE_PACKED __attribute__ ((__packed__))
+#else
+# define _GL_ATTRIBUTE_PACKED
+#endif
+
+#if _GL_HAS_ATTRIBUTE (pure)
+# define _GL_ATTRIBUTE_PURE __attribute__ ((__pure__))
+#else
+# define _GL_ATTRIBUTE_PURE
+#endif
+
+#if _GL_HAS_ATTRIBUTE (returns_nonnull)
+# define _GL_ATTRIBUTE_RETURNS_NONNULL __attribute__ ((__returns_nonnull__))
+#else
+# define _GL_ATTRIBUTE_RETURNS_NONNULL
+#endif
+
+#if _GL_HAS_ATTRIBUTE (sentinel)
+# define _GL_ATTRIBUTE_SENTINEL(pos) __attribute__ ((__sentinel__ pos))
+#else
+# define _GL_ATTRIBUTE_SENTINEL(pos)
+#endif
+
+]dnl There is no _GL_ATTRIBUTE_VISIBILITY; see m4/visibility.m4 instead.
+[
+/* To support C++ as well as C, use _GL_UNUSED_LABEL with trailing ';'.  */
+#if !defined __cplusplus || _GL_GNUC_PREREQ (4, 5)
+# define _GL_UNUSED_LABEL _GL_ATTRIBUTE_MAYBE_UNUSED
+#else
+# define _GL_UNUSED_LABEL
+#endif
+])
+  AH_VERBATIM([async_safe],
+[/* The _GL_ASYNC_SAFE marker should be attached to functions that are
+   signal handlers (for signals other than SIGABRT, SIGPIPE) or can be
+   invoked from such signal handlers.  Such functions have some restrictions:
+     * All functions that it calls should be marked _GL_ASYNC_SAFE as well,
+       or should be listed as async-signal-safe in POSIX
+       <https://pubs.opengroup.org/onlinepubs/9699919799/functions/V2_chap02.html#tag_15_04>
+       section 2.4.3.  Note that malloc(), sprintf(), and fwrite(), in
+       particular, are NOT async-signal-safe.
+     * All memory locations (variables and struct fields) that these functions
+       access must be marked 'volatile'.  This holds for both read and write
+       accesses.  Otherwise the compiler might optimize away stores to and
+       reads from such locations that occur in the program, depending on its
+       data flow analysis.  For example, when the program contains a loop
+       that is intended to inspect a variable set from within a signal handler
+           while (!signal_occurred)
+             ;
+       the compiler is allowed to transform this into an endless loop if the
+       variable 'signal_occurred' is not declared 'volatile'.
+   Additionally, recall that:
+     * A signal handler should not modify errno (except if it is a handler
+       for a fatal signal and ends by raising the same signal again, thus
+       provoking the termination of the process).  If it invokes a function
+       that may clobber errno, it needs to save and restore the value of
+       errno.  */
+#define _GL_ASYNC_SAFE
+])
+  AH_VERBATIM([micro_optimizations],
+[/* _GL_CMP (n1, n2) performs a three-valued comparison on n1 vs. n2, where
+   n1 and n2 are expressions without side effects, that evaluate to real
+   numbers (excluding NaN).
+   It returns
+     1  if n1 > n2
+     0  if n1 == n2
+     -1 if n1 < n2
+   The naïve code   (n1 > n2 ? 1 : n1 < n2 ? -1 : 0)  produces a conditional
+   jump with nearly all GCC versions up to GCC 10.
+   This variant     (n1 < n2 ? -1 : n1 > n2)  produces a conditional with many
+   GCC versions up to GCC 9.
+   The better code  (n1 > n2) - (n1 < n2)  from Hacker's Delight § 2-9
+   avoids conditional jumps in all GCC versions >= 3.4.  */
+#define _GL_CMP(n1, n2) (((n1) > (n2)) - ((n1) < (n2)))
+])
+  dnl Hint which direction to take regarding cross-compilation guesses:
+  dnl When a user installs a program on a platform they are not intimately
+  dnl familiar with, --enable-cross-guesses=conservative is the appropriate
+  dnl choice.  It implements the "If we don't know, assume the worst" principle.
+  dnl However, when an operating system developer (on a platform which is not
+  dnl yet known to gnulib) builds packages for their platform, they want to
+  dnl expose, not hide, possible platform bugs; in this case,
+  dnl --enable-cross-guesses=risky is the appropriate choice.
+  dnl Sets the variables
+  dnl gl_cross_guess_normal    (to be used when 'yes' is good and 'no' is bad),
+  dnl gl_cross_guess_inverted  (to be used when 'no' is good and 'yes' is bad).
+  AC_ARG_ENABLE([cross-guesses],
+    [AS_HELP_STRING([--enable-cross-guesses={conservative|risky}],
+       [specify policy for cross-compilation guesses])],
+    [if test "x$enableval" != xconservative && test "x$enableval" != xrisky; then
+       AC_MSG_WARN([invalid argument supplied to --enable-cross-guesses])
+       enableval=conservative
+     fi
+     gl_cross_guesses="$enableval"],
+    [gl_cross_guesses=conservative])
+  if test $gl_cross_guesses = risky; then
+    gl_cross_guess_normal="guessing yes"
+    gl_cross_guess_inverted="guessing no"
+  else
+    gl_cross_guess_normal="guessing no"
+    gl_cross_guess_inverted="guessing yes"
+  fi
+  dnl Preparation for running test programs:
+  dnl Tell glibc to write diagnostics from -D_FORTIFY_SOURCE=2 to stderr, not
+  dnl to /dev/tty, so they can be redirected to log files.  Such diagnostics
+  dnl arise e.g., in the macros gl_PRINTF_DIRECTIVE_N, gl_SNPRINTF_DIRECTIVE_N.
+  LIBC_FATAL_STDERR_=1
+  export LIBC_FATAL_STDERR_
+])
+
+# gl_MODULE_INDICATOR_CONDITION
+# expands to a C preprocessor expression that evaluates to 1 or 0, depending
+# whether a gnulib module that has been requested shall be considered present
+# or not.
+m4_define([gl_MODULE_INDICATOR_CONDITION], [1])
+
+# gl_MODULE_INDICATOR_SET_VARIABLE([modulename])
+# sets the shell variable that indicates the presence of the given module to
+# a C preprocessor expression that will evaluate to 1.
+AC_DEFUN([gl_MODULE_INDICATOR_SET_VARIABLE],
+[
+  gl_MODULE_INDICATOR_SET_VARIABLE_AUX(
+    [GNULIB_[]m4_translit([[$1]],
+                          [abcdefghijklmnopqrstuvwxyz./-],
+                          [ABCDEFGHIJKLMNOPQRSTUVWXYZ___])],
+    [gl_MODULE_INDICATOR_CONDITION])
+])
+
+# gl_MODULE_INDICATOR_SET_VARIABLE_AUX([variable])
+# modifies the shell variable to include the gl_MODULE_INDICATOR_CONDITION.
+# The shell variable's value is a C preprocessor expression that evaluates
+# to 0 or 1.
+AC_DEFUN([gl_MODULE_INDICATOR_SET_VARIABLE_AUX],
+[
+  m4_if(m4_defn([gl_MODULE_INDICATOR_CONDITION]), [1],
+    [
+     dnl Simplify the expression VALUE || 1 to 1.
+     $1=1
+    ],
+    [gl_MODULE_INDICATOR_SET_VARIABLE_AUX_OR([$1],
+                                             [gl_MODULE_INDICATOR_CONDITION])])
+])
+
+# gl_MODULE_INDICATOR_SET_VARIABLE_AUX_OR([variable], [condition])
+# modifies the shell variable to include the given condition.  The shell
+# variable's value is a C preprocessor expression that evaluates to 0 or 1.
+AC_DEFUN([gl_MODULE_INDICATOR_SET_VARIABLE_AUX_OR],
+[
+  dnl Simplify the expression 1 || CONDITION to 1.
+  if test "$[]$1" != 1; then
+    dnl Simplify the expression 0 || CONDITION to CONDITION.
+    if test "$[]$1" = 0; then
+      $1=$2
+    else
+      $1="($[]$1 || $2)"
+    fi
+  fi
+])
+
+# gl_MODULE_INDICATOR([modulename])
+# defines a C macro indicating the presence of the given module
+# in a location where it can be used.
+#                                             |  Value  |   Value   |
+#                                             | in lib/ | in tests/ |
+# --------------------------------------------+---------+-----------+
+# Module present among main modules:          |    1    |     1     |
+# --------------------------------------------+---------+-----------+
+# Module present among tests-related modules: |    0    |     1     |
+# --------------------------------------------+---------+-----------+
+# Module not present at all:                  |    0    |     0     |
+# --------------------------------------------+---------+-----------+
+AC_DEFUN([gl_MODULE_INDICATOR],
+[
+  AC_DEFINE_UNQUOTED([GNULIB_]m4_translit([[$1]],
+      [abcdefghijklmnopqrstuvwxyz./-],
+      [ABCDEFGHIJKLMNOPQRSTUVWXYZ___]),
+    [gl_MODULE_INDICATOR_CONDITION],
+    [Define to a C preprocessor expression that evaluates to 1 or 0,
+     depending whether the gnulib module $1 shall be considered present.])
+])
+
+# gl_MODULE_INDICATOR_FOR_TESTS([modulename])
+# defines a C macro indicating the presence of the given module
+# in lib or tests. This is useful to determine whether the module
+# should be tested.
+#                                             |  Value  |   Value   |
+#                                             | in lib/ | in tests/ |
+# --------------------------------------------+---------+-----------+
+# Module present among main modules:          |    1    |     1     |
+# --------------------------------------------+---------+-----------+
+# Module present among tests-related modules: |    1    |     1     |
+# --------------------------------------------+---------+-----------+
+# Module not present at all:                  |    0    |     0     |
+# --------------------------------------------+---------+-----------+
+AC_DEFUN([gl_MODULE_INDICATOR_FOR_TESTS],
+[
+  AC_DEFINE([GNULIB_TEST_]m4_translit([[$1]],
+      [abcdefghijklmnopqrstuvwxyz./-],
+      [ABCDEFGHIJKLMNOPQRSTUVWXYZ___]), [1],
+    [Define to 1 when the gnulib module $1 should be tested.])
+])
+
+# gl_ASSERT_NO_GNULIB_POSIXCHECK
+# asserts that there will never be a need to #define GNULIB_POSIXCHECK.
+# and thereby enables an optimization of configure and config.h.
+# Used by Emacs.
+AC_DEFUN([gl_ASSERT_NO_GNULIB_POSIXCHECK],
+[
+  dnl Override gl_WARN_ON_USE_PREPARE.
+  dnl But hide this definition from 'aclocal'.
+  AC_DEFUN([gl_W][ARN_ON_USE_PREPARE], [])
+])
+
+# gl_ASSERT_NO_GNULIB_TESTS
+# asserts that there will be no gnulib tests in the scope of the configure.ac
+# and thereby enables an optimization of config.h.
+# Used by Emacs.
+AC_DEFUN([gl_ASSERT_NO_GNULIB_TESTS],
+[
+  dnl Override gl_MODULE_INDICATOR_FOR_TESTS.
+  AC_DEFUN([gl_MODULE_INDICATOR_FOR_TESTS], [])
+])
+
+# Test whether <features.h> exists.
+# Set HAVE_FEATURES_H.
+AC_DEFUN([gl_FEATURES_H],
+[
+  AC_CHECK_HEADERS_ONCE([features.h])
+  if test $ac_cv_header_features_h = yes; then
+    HAVE_FEATURES_H=1
+  else
+    HAVE_FEATURES_H=0
+  fi
+  AC_SUBST([HAVE_FEATURES_H])
+])
+
+# gl_PROG_CC_C99
+# Modifies the value of the shell variable CC in an attempt to make $CC
+# understand ISO C99 source code.
+AC_DEFUN([gl_PROG_CC_C99],
+[
+  dnl Just use AC_PROG_CC_C99.
+  dnl When AC_PROG_CC_C99 and AC_PROG_CC_STDC are used together, the substituted
+  dnl value of CC will contain the C99 enabling options twice. But this is only
+  dnl a cosmetic problem.
+  dnl With Autoconf >= 2.70, use AC_PROG_CC since it implies AC_PROG_CC_C99;
+  dnl this avoids a "warning: The macro `AC_PROG_CC_C99' is obsolete."
+  m4_version_prereq([2.70],
+    [AC_REQUIRE([AC_PROG_CC])],
+    [AC_REQUIRE([AC_PROG_CC_C99])])
+])
+
+# gl_PROG_AR_RANLIB
+# Determines the values for AR, ARFLAGS, RANLIB that fit with the compiler.
+# The user can set the variables AR, ARFLAGS, RANLIB if he wants to override
+# the values.
+AC_DEFUN([gl_PROG_AR_RANLIB],
+[
+  dnl Minix 3 comes with two toolchains: The Amsterdam Compiler Kit compiler
+  dnl as "cc", and GCC as "gcc". They have different object file formats and
+  dnl library formats. In particular, the GNU binutils programs ar and ranlib
+  dnl produce libraries that work only with gcc, not with cc.
+  AC_REQUIRE([AC_PROG_CC])
+  dnl The '][' hides this use from 'aclocal'.
+  AC_BEFORE([$0], [A][M_PROG_AR])
+  AC_CACHE_CHECK([for Minix Amsterdam compiler], [gl_cv_c_amsterdam_compiler],
+    [
+      AC_EGREP_CPP([Amsterdam],
+        [
+#ifdef __ACK__
+Amsterdam
+#endif
+        ],
+        [gl_cv_c_amsterdam_compiler=yes],
+        [gl_cv_c_amsterdam_compiler=no])
+    ])
+
+  dnl Don't compete with AM_PROG_AR's decision about AR/ARFLAGS if we are not
+  dnl building with __ACK__.
+  if test $gl_cv_c_amsterdam_compiler = yes; then
+    if test -z "$AR"; then
+      AR='cc -c.a'
+    fi
+    if test -z "$ARFLAGS"; then
+      ARFLAGS='-o'
+    fi
+  else
+    dnl AM_PROG_AR was added in automake v1.11.2.  AM_PROG_AR does not AC_SUBST
+    dnl ARFLAGS variable (it is filed into Makefile.in directly by automake
+    dnl script on-demand, if not specified by ./configure of course).
+    dnl Don't AC_REQUIRE the AM_PROG_AR otherwise the code for __ACK__ above
+    dnl will be ignored.  Also, pay attention to call AM_PROG_AR in else block
+    dnl because AM_PROG_AR is written so it could re-set AR variable even for
+    dnl __ACK__.  It may seem like its easier to avoid calling the macro here,
+    dnl but we need to AC_SUBST both AR/ARFLAGS (thus those must have some good
+    dnl default value and automake should usually know them).
+    dnl
+    dnl The '][' hides this use from 'aclocal'.
+    m4_ifdef([A][M_PROG_AR], [A][M_PROG_AR], [:])
+  fi
+
+  dnl In case the code above has not helped with setting AR/ARFLAGS, use
+  dnl Automake-documented default values for AR and ARFLAGS, but prefer
+  dnl ${host}-ar over ar (useful for cross-compiling).
+  AC_CHECK_TOOL([AR], [ar], [ar])
+  if test -z "$ARFLAGS"; then
+    ARFLAGS='cr'
+  fi
+
+  AC_SUBST([AR])
+  AC_SUBST([ARFLAGS])
+  if test -z "$RANLIB"; then
+    if test $gl_cv_c_amsterdam_compiler = yes; then
+      RANLIB=':'
+    else
+      dnl Use the ranlib program if it is available.
+      AC_PROG_RANLIB
+    fi
+  fi
+  AC_SUBST([RANLIB])
+])
+
+# AC_C_RESTRICT
+# This definition is copied from post-2.70 Autoconf and overrides the
+# AC_C_RESTRICT macro from autoconf 2.60..2.70.
+m4_version_prereq([2.70.1], [], [
+AC_DEFUN([AC_C_RESTRICT],
+[AC_CACHE_CHECK([for C/C++ restrict keyword], [ac_cv_c_restrict],
+  [ac_cv_c_restrict=no
+   # Put '__restrict__' first, to avoid problems with glibc and non-GCC; see:
+   # https://lists.gnu.org/archive/html/bug-autoconf/2016-02/msg00006.html
+   # Put 'restrict' last, because C++ lacks it.
+   for ac_kw in __restrict__ __restrict _Restrict restrict; do
+     AC_COMPILE_IFELSE(
+      [AC_LANG_PROGRAM(
+         [[typedef int *int_ptr;
+           int foo (int_ptr $ac_kw ip) { return ip[0]; }
+           int bar (int [$ac_kw]); /* Catch GCC bug 14050.  */
+           int bar (int ip[$ac_kw]) { return ip[0]; }
+         ]],
+         [[int s[1];
+           int *$ac_kw t = s;
+           t[0] = 0;
+           return foo (t) + bar (t);
+         ]])],
+      [ac_cv_c_restrict=$ac_kw])
+     test "$ac_cv_c_restrict" != no && break
+   done
+  ])
+ AH_VERBATIM([restrict],
+[/* Define to the equivalent of the C99 'restrict' keyword, or to
+   nothing if this is not supported.  Do not define if restrict is
+   supported only directly.  */
+#undef restrict
+/* Work around a bug in older versions of Sun C++, which did not
+   #define __restrict__ or support _Restrict or __restrict__
+   even though the corresponding Sun C compiler ended up with
+   "#define restrict _Restrict" or "#define restrict __restrict__"
+   in the previous line.  This workaround can be removed once
+   we assume Oracle Developer Studio 12.5 (2016) or later.  */
+#if defined __SUNPRO_CC && !defined __RESTRICT && !defined __restrict__
+# define _Restrict
+# define __restrict__
+#endif])
+ case $ac_cv_c_restrict in
+   restrict) ;;
+   no) AC_DEFINE([restrict], []) ;;
+   *)  AC_DEFINE_UNQUOTED([restrict], [$ac_cv_c_restrict]) ;;
+ esac
+])# AC_C_RESTRICT
+])
+
+# gl_BIGENDIAN
+# is like AC_C_BIGENDIAN, except that it can be AC_REQUIREd.
+# Note that AC_REQUIRE([AC_C_BIGENDIAN]) does not work reliably because some
+# macros invoke AC_C_BIGENDIAN with arguments.
+AC_DEFUN([gl_BIGENDIAN],
+[
+  AC_C_BIGENDIAN
+])
+
+# A temporary file descriptor.
+# Must be less than 10, because dash 0.5.8 does not support redirections
+# with multi-digit file descriptors.
+m4_define([GL_TMP_FD], 9)
+
+# gl_SILENT(command)
+# executes command, but without the normal configure output.
+# This is useful when you want to invoke AC_CACHE_CHECK (or AC_CHECK_FUNC etc.)
+# inside another AC_CACHE_CHECK.
+AC_DEFUN([gl_SILENT],
+[
+  exec GL_TMP_FD>&AS_MESSAGE_FD AS_MESSAGE_FD>/dev/null
+  $1
+  exec AS_MESSAGE_FD>&GL_TMP_FD GL_TMP_FD>&-
+])
+
+# gl_CACHE_VAL_SILENT(cache-id, command-to-set-it)
+# is like AC_CACHE_VAL(cache-id, command-to-set-it), except that it does not
+# output a spurious "(cached)" mark in the midst of other configure output.
+# This macro should be used instead of AC_CACHE_VAL when it is not surrounded
+# by an AC_MSG_CHECKING/AC_MSG_RESULT pair.
+AC_DEFUN([gl_CACHE_VAL_SILENT],
+[
+  gl_SILENT([
+    AC_CACHE_VAL([$1], [$2])
+  ])
+])
+
+dnl Expands to some code for use in .c programs that, on native Windows, defines
+dnl the Microsoft deprecated alias function names to the underscore-prefixed
+dnl actual function names. With this macro, these function names are available
+dnl without linking with '-loldnames' and without generating warnings.
+dnl Usage: Use it after all system header files are included.
+dnl          #include <...>
+dnl          #include <...>
+dnl          ]GL_MDA_DEFINES[
+dnl          ...
+AC_DEFUN([GL_MDA_DEFINES],[
+AC_REQUIRE([_GL_MDA_DEFINES])
+[$gl_mda_defines]
+])
+AC_DEFUN([_GL_MDA_DEFINES],
+[gl_mda_defines='
+#if defined _WIN32 && !defined __CYGWIN__
+#define access    _access
+#define chdir     _chdir
+#define chmod     _chmod
+#define close     _close
+#define creat     _creat
+#define dup       _dup
+#define dup2      _dup2
+#define ecvt      _ecvt
+#define execl     _execl
+#define execle    _execle
+#define execlp    _execlp
+#define execv     _execv
+#define execve    _execve
+#define execvp    _execvp
+#define execvpe   _execvpe
+#define fcloseall _fcloseall
+#define fcvt      _fcvt
+#define fdopen    _fdopen
+#define fileno    _fileno
+#define gcvt      _gcvt
+#define getcwd    _getcwd
+#define getpid    _getpid
+#define getw      _getw
+#define isatty    _isatty
+#define j0        _j0
+#define j1        _j1
+#define jn        _jn
+#define lfind     _lfind
+#define lsearch   _lsearch
+#define lseek     _lseek
+#define memccpy   _memccpy
+#define mkdir     _mkdir
+#define mktemp    _mktemp
+#define open      _open
+#define putenv    _putenv
+#define putw      _putw
+#define read      _read
+#define rmdir     _rmdir
+#define strdup    _strdup
+#define swab      _swab
+#define tempnam   _tempnam
+#define tzset     _tzset
+#define umask     _umask
+#define unlink    _unlink
+#define utime     _utime
+#define wcsdup    _wcsdup
+#define write     _write
+#define y0        _y0
+#define y1        _y1
+#define yn        _yn
+#endif
+'
+])
diff --git a/m4/gnulib-comp.m4 b/m4/gnulib-comp.m4
new file mode 100644
index 0000000..6032dcd
--- /dev/null
+++ b/m4/gnulib-comp.m4
@@ -0,0 +1,2320 @@
+# DO NOT EDIT! GENERATED AUTOMATICALLY!
+# Copyright (C) 2002-2020 Free Software Foundation, Inc.
+#
+# This file is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This file is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this file.  If not, see <https://www.gnu.org/licenses/>.
+#
+# As a special exception to the GNU General Public License,
+# this file may be distributed as part of a program that
+# contains a configuration script generated by Autoconf, under
+# the same distribution terms as the rest of that program.
+#
+# Generated by gnulib-tool.
+#
+# This file represents the compiled summary of the specification in
+# gnulib-cache.m4. It lists the computed macro invocations that need
+# to be invoked from configure.ac.
+# In projects that use version control, this file can be treated like
+# other built files.
+
+
+# This macro should be invoked from ./configure.ac, in the section
+# "Checks for programs", right after AC_PROG_CC, and certainly before
+# any checks for libraries, header files, types and library functions.
+AC_DEFUN([gl_EARLY],
+[
+  m4_pattern_forbid([^gl_[A-Z]])dnl the gnulib macro namespace
+  m4_pattern_allow([^gl_ES$])dnl a valid locale name
+  m4_pattern_allow([^gl_LIBOBJS$])dnl a variable
+  m4_pattern_allow([^gl_LTLIBOBJS$])dnl a variable
+
+  # Pre-early section.
+  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+  AC_REQUIRE([gl_PROG_AR_RANLIB])
+
+  AC_REQUIRE([AM_PROG_CC_C_O])
+  # Code from module absolute-header:
+  # Code from module accept:
+  # Code from module access:
+  # Code from module alloca:
+  # Code from module alloca-opt:
+  # Code from module announce-gen:
+  # Code from module arpa_inet:
+  # Code from module array-mergesort:
+  # Code from module assure:
+  # Code from module at-internal:
+  # Code from module attribute:
+  # Code from module base32:
+  # Code from module basename-lgpl:
+  # Code from module binary-io:
+  # Code from module bind:
+  # Code from module bitrotate:
+  # Code from module btowc:
+  # Code from module builtin-expect:
+  # Code from module byteswap:
+  # Code from module c-ctype:
+  # Code from module c-strcase:
+  # Code from module c-strcaseeq:
+  # Code from module c-strcasestr:
+  # Code from module c99:
+  # Code from module canonicalize:
+  # Code from module chdir:
+  # Code from module chdir-long:
+  # Code from module clock-time:
+  # Code from module cloexec:
+  # Code from module close:
+  # Code from module closedir:
+  # Code from module concat-filename:
+  # Code from module connect:
+  # Code from module crypto/af_alg:
+  # Code from module crypto/md2:
+  # Code from module crypto/md4:
+  # Code from module crypto/md5:
+  # Code from module crypto/md5-buffer:
+  # Code from module crypto/sha1:
+  # Code from module crypto/sha1-buffer:
+  # Code from module crypto/sha256:
+  # Code from module crypto/sha256-buffer:
+  # Code from module crypto/sha512:
+  # Code from module crypto/sha512-buffer:
+  # Code from module ctype:
+  # Code from module d-ino:
+  # Code from module dirent:
+  # Code from module dirfd:
+  # Code from module dirname:
+  # Code from module dirname-lgpl:
+  # Code from module double-slash-root:
+  # Code from module dup:
+  # Code from module dup2:
+  # Code from module environ:
+  # Code from module errno:
+  # Code from module error:
+  # Code from module exitfail:
+  # Code from module extensions:
+  # Code from module extern-inline:
+  # Code from module fatal-signal:
+  # Code from module fchdir:
+  # Code from module fcntl:
+  # Code from module fcntl-h:
+  # Code from module fd-hook:
+  # Code from module fd-safer-flag:
+  # Code from module fdopendir:
+  # Code from module fflush:
+  AC_REQUIRE([gl_SET_LARGEFILE_SOURCE])
+  # Code from module file-set:
+  # Code from module filename:
+  # Code from module filenamecat-lgpl:
+  # Code from module findprog-in:
+  # Code from module flexmember:
+  # Code from module float:
+  # Code from module flock:
+  # Code from module fnmatch:
+  # Code from module fnmatch-gnu:
+  # Code from module fnmatch-h:
+  # Code from module fopen:
+  # Code from module fopen-gnu:
+  # Code from module fpurge:
+  # Code from module freading:
+  # Code from module free-posix:
+  # Code from module fseek:
+  # Code from module fseeko:
+  AC_REQUIRE([gl_SET_LARGEFILE_SOURCE])
+  # Code from module fstat:
+  # Code from module fstatat:
+  # Code from module ftell:
+  # Code from module ftello:
+  AC_REQUIRE([gl_SET_LARGEFILE_SOURCE])
+  # Code from module futimens:
+  # Code from module getaddrinfo:
+  # Code from module getcwd:
+  # Code from module getcwd-lgpl:
+  # Code from module getdelim:
+  # Code from module getdtablesize:
+  # Code from module getgroups:
+  # Code from module getline:
+  # Code from module getopt-gnu:
+  # Code from module getopt-posix:
+  # Code from module getpass:
+  # Code from module getpass-gnu:
+  # Code from module getpeername:
+  # Code from module getprogname:
+  # Code from module getrandom:
+  # Code from module getsockname:
+  # Code from module gettext-h:
+  # Code from module gettime:
+  # Code from module gettimeofday:
+  # Code from module git-version-gen:
+  # Code from module gitlog-to-changelog:
+  # Code from module gnumakefile:
+  # Code from module gnupload:
+  # Code from module gperf:
+  # Code from module group-member:
+  # Code from module hard-locale:
+  # Code from module hash:
+  # Code from module hash-pjw:
+  # Code from module hash-triple-simple:
+  # Code from module havelib:
+  # Code from module hostent:
+  # Code from module iconv:
+  # Code from module iconv-h:
+  # Code from module idx:
+  # Code from module include_next:
+  # Code from module inet_ntop:
+  # Code from module inline:
+  # Code from module intprops:
+  # Code from module inttypes:
+  # Code from module inttypes-incomplete:
+  # Code from module ioctl:
+  # Code from module isblank:
+  # Code from module iswblank:
+  # Code from module iswdigit:
+  # Code from module iswxdigit:
+  # Code from module langinfo:
+  # Code from module largefile:
+  AC_REQUIRE([AC_SYS_LARGEFILE])
+  # Code from module libc-config:
+  # Code from module libunistring-optional:
+  # Code from module limits-h:
+  # Code from module link:
+  # Code from module listen:
+  # Code from module localcharset:
+  # Code from module locale:
+  # Code from module localeconv:
+  # Code from module lock:
+  # Code from module lseek:
+  # Code from module lstat:
+  # Code from module maintainer-makefile:
+  # Code from module malloc-posix:
+  # Code from module malloca:
+  # Code from module mbchar:
+  # Code from module mbiter:
+  # Code from module mbrtowc:
+  # Code from module mbsinit:
+  # Code from module mbsrtowcs:
+  # Code from module mbtowc:
+  # Code from module memchr:
+  # Code from module mempcpy:
+  # Code from module memrchr:
+  # Code from module minmax:
+  # Code from module mkdir:
+  # Code from module mkostemp:
+  # Code from module mkstemp:
+  # Code from module mktime:
+  # Code from module mktime-internal:
+  # Code from module msvc-inval:
+  # Code from module msvc-nothrow:
+  # Code from module multiarch:
+  # Code from module nanosleep:
+  # Code from module netdb:
+  # Code from module netinet_in:
+  # Code from module nl_langinfo:
+  # Code from module nocrash:
+  # Code from module open:
+  # Code from module openat:
+  # Code from module openat-die:
+  # Code from module openat-h:
+  # Code from module opendir:
+  # Code from module pathmax:
+  # Code from module pipe-posix:
+  # Code from module pipe2:
+  # Code from module pipe2-safer:
+  # Code from module posix_spawn:
+  # Code from module posix_spawn-internal:
+  # Code from module posix_spawn_file_actions_addchdir:
+  # Code from module posix_spawn_file_actions_addclose:
+  # Code from module posix_spawn_file_actions_adddup2:
+  # Code from module posix_spawn_file_actions_addopen:
+  # Code from module posix_spawn_file_actions_destroy:
+  # Code from module posix_spawn_file_actions_init:
+  # Code from module posix_spawnattr_destroy:
+  # Code from module posix_spawnattr_init:
+  # Code from module posix_spawnattr_setflags:
+  # Code from module posix_spawnattr_setpgroup:
+  # Code from module posix_spawnattr_setsigmask:
+  # Code from module posix_spawnp:
+  # Code from module quote:
+  # Code from module quotearg:
+  # Code from module quotearg-simple:
+  # Code from module raise:
+  # Code from module rawmemchr:
+  # Code from module readdir:
+  # Code from module readlink:
+  # Code from module realloc-posix:
+  # Code from module recv:
+  # Code from module regex:
+  # Code from module rewinddir:
+  # Code from module same-inode:
+  # Code from module save-cwd:
+  # Code from module sched:
+  # Code from module scratch_buffer:
+  # Code from module secure_getenv:
+  # Code from module select:
+  # Code from module send:
+  # Code from module servent:
+  # Code from module setlocale-null:
+  # Code from module setsockopt:
+  # Code from module sh-filename:
+  # Code from module sigaction:
+  # Code from module signal-h:
+  # Code from module sigpipe:
+  # Code from module sigprocmask:
+  # Code from module size_max:
+  # Code from module snippet/_Noreturn:
+  # Code from module snippet/arg-nonnull:
+  # Code from module snippet/c++defs:
+  # Code from module snippet/unused-parameter:
+  # Code from module snippet/warn-on-use:
+  # Code from module snprintf:
+  # Code from module socket:
+  # Code from module socketlib:
+  # Code from module sockets:
+  # Code from module socklen:
+  # Code from module spawn:
+  # Code from module spawn-pipe:
+  # Code from module ssize_t:
+  # Code from module stat:
+  # Code from module stat-time:
+  # Code from module std-gnu11:
+  # Code from module stdalign:
+  # Code from module stdbool:
+  # Code from module stddef:
+  # Code from module stdint:
+  # Code from module stdio:
+  # Code from module stdlib:
+  # Code from module stpcpy:
+  # Code from module strcase:
+  # Code from module strchrnul:
+  # Code from module strdup-posix:
+  # Code from module streq:
+  # Code from module strerror:
+  # Code from module strerror-override:
+  # Code from module strerror_r-posix:
+  # Code from module string:
+  # Code from module strings:
+  # Code from module strndup:
+  # Code from module strnlen:
+  # Code from module strnlen1:
+  # Code from module strpbrk:
+  # Code from module strptime:
+  # Code from module strtok_r:
+  # Code from module strtol:
+  # Code from module strtoll:
+  # Code from module symlink:
+  # Code from module sys_file:
+  # Code from module sys_ioctl:
+  # Code from module sys_random:
+  # Code from module sys_select:
+  # Code from module sys_socket:
+  # Code from module sys_stat:
+  # Code from module sys_time:
+  # Code from module sys_types:
+  # Code from module sys_uio:
+  # Code from module sys_wait:
+  # Code from module tempname:
+  # Code from module thread-optim:
+  # Code from module threadlib:
+  gl_THREADLIB_EARLY
+  # Code from module time:
+  # Code from module time_r:
+  # Code from module timegm:
+  # Code from module timespec:
+  # Code from module tmpdir:
+  # Code from module u64:
+  # Code from module unicase/base:
+  # Code from module unicase/cased:
+  # Code from module unicase/empty-prefix-context:
+  # Code from module unicase/empty-suffix-context:
+  # Code from module unicase/ignorable:
+  # Code from module unicase/special-casing:
+  # Code from module unicase/tolower:
+  # Code from module unicase/u8-casemap:
+  # Code from module unicase/u8-tolower:
+  # Code from module unictype/base:
+  # Code from module unictype/combining-class:
+  # Code from module unictype/property-soft-dotted:
+  # Code from module uninorm/base:
+  # Code from module uninorm/decompose-internal:
+  # Code from module uninorm/u8-normalize:
+  # Code from module unistd:
+  # Code from module unistd-safer:
+  # Code from module unistr/base:
+  # Code from module unistr/u8-cpy:
+  # Code from module unistr/u8-mbtouc-unsafe:
+  # Code from module unistr/u8-strlen:
+  # Code from module unistr/u8-uctomb:
+  # Code from module unitypes:
+  # Code from module uniwidth/base:
+  # Code from module uniwidth/width:
+  # Code from module unlink:
+  # Code from module unlocked-io:
+  # Code from module update-copyright:
+  # Code from module useless-if-before-free:
+  # Code from module utime:
+  # Code from module utime-h:
+  # Code from module utimens:
+  # Code from module vasnprintf:
+  # Code from module vasprintf:
+  # Code from module vc-list-files:
+  # Code from module verify:
+  # Code from module vsnprintf:
+  # Code from module wait-process:
+  # Code from module waitpid:
+  # Code from module warnings:
+  # Code from module wchar:
+  # Code from module wcrtomb:
+  # Code from module wctype-h:
+  # Code from module wcwidth:
+  # Code from module windows-mutex:
+  # Code from module windows-once:
+  # Code from module windows-recmutex:
+  # Code from module windows-rwlock:
+  # Code from module windows-spawn:
+  # Code from module wmemchr:
+  # Code from module wmempcpy:
+  # Code from module write:
+  # Code from module xalloc:
+  # Code from module xalloc-die:
+  # Code from module xalloc-oversized:
+  # Code from module xmemdup0:
+  # Code from module xsize:
+  # Code from module xstrndup:
+])
+
+# This macro should be invoked from ./configure.ac, in the section
+# "Check for header files, types and library functions".
+AC_DEFUN([gl_INIT],
+[
+  AM_CONDITIONAL([GL_COND_LIBTOOL], [false])
+  gl_cond_libtool=false
+  gl_libdeps=
+  gl_ltlibdeps=
+  gl_m4_base='m4'
+  m4_pushdef([AC_LIBOBJ], m4_defn([gl_LIBOBJ]))
+  m4_pushdef([AC_REPLACE_FUNCS], m4_defn([gl_REPLACE_FUNCS]))
+  m4_pushdef([AC_LIBSOURCES], m4_defn([gl_LIBSOURCES]))
+  m4_pushdef([gl_LIBSOURCES_LIST], [])
+  m4_pushdef([gl_LIBSOURCES_DIR], [])
+  gl_COMMON
+  gl_source_base='lib'
+  AC_REQUIRE([gl_HEADER_SYS_SOCKET])
+  if test "$ac_cv_header_winsock2_h" = yes; then
+    AC_LIBOBJ([accept])
+  fi
+  gl_SYS_SOCKET_MODULE_INDICATOR([accept])
+  gl_FUNC_ACCESS
+  if test $REPLACE_ACCESS = 1; then
+    AC_LIBOBJ([access])
+  fi
+  gl_UNISTD_MODULE_INDICATOR([access])
+  gl_FUNC_ALLOCA
+  gl_HEADER_ARPA_INET
+  AC_PROG_MKDIR_P
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  gl_FUNC_BASE32
+  AC_REQUIRE([gl_HEADER_SYS_SOCKET])
+  if test "$ac_cv_header_winsock2_h" = yes; then
+    AC_LIBOBJ([bind])
+  fi
+  gl_SYS_SOCKET_MODULE_INDICATOR([bind])
+  gl_FUNC_BTOWC
+  if test $HAVE_BTOWC = 0 || test $REPLACE_BTOWC = 1; then
+    AC_LIBOBJ([btowc])
+    gl_PREREQ_BTOWC
+  fi
+  gl_WCHAR_MODULE_INDICATOR([btowc])
+  gl___BUILTIN_EXPECT
+  gl_BYTESWAP
+  gl_FUNC_CANONICALIZE_FILENAME_MODE
+  gl_MODULE_INDICATOR([canonicalize])
+  gl_MODULE_INDICATOR_FOR_TESTS([canonicalize])
+  gl_STDLIB_MODULE_INDICATOR([canonicalize_file_name])
+  gl_UNISTD_MODULE_INDICATOR([chdir])
+  gl_FUNC_CHDIR_LONG
+  if test $gl_cv_have_unlimited_file_name_length = no; then
+    AC_LIBOBJ([chdir-long])
+    gl_PREREQ_CHDIR_LONG
+  fi
+  gl_CLOCK_TIME
+  gl_MODULE_INDICATOR_FOR_TESTS([cloexec])
+  gl_FUNC_CLOSE
+  if test $REPLACE_CLOSE = 1; then
+    AC_LIBOBJ([close])
+  fi
+  gl_UNISTD_MODULE_INDICATOR([close])
+  gl_FUNC_CLOSEDIR
+  if test $HAVE_CLOSEDIR = 0 || test $REPLACE_CLOSEDIR = 1; then
+    AC_LIBOBJ([closedir])
+  fi
+  gl_DIRENT_MODULE_INDICATOR([closedir])
+  AC_REQUIRE([gl_HEADER_SYS_SOCKET])
+  if test "$ac_cv_header_winsock2_h" = yes; then
+    AC_LIBOBJ([connect])
+  fi
+  gl_SYS_SOCKET_MODULE_INDICATOR([connect])
+  gl_AF_ALG
+  AC_REQUIRE([AC_C_RESTRICT])
+  AC_REQUIRE([AC_C_RESTRICT])
+  gl_MD4
+  AC_DEFINE([GL_COMPILE_CRYPTO_STREAM], 1, [Compile Gnulib crypto stream ops.])
+  AC_REQUIRE([AC_C_RESTRICT])
+  gl_MD5
+  AC_DEFINE([GL_COMPILE_CRYPTO_STREAM], 1, [Compile Gnulib crypto stream ops.])
+  AC_REQUIRE([AC_C_RESTRICT])
+  gl_SHA1
+  AC_DEFINE([GL_COMPILE_CRYPTO_STREAM], 1, [Compile Gnulib crypto stream ops.])
+  AC_REQUIRE([AC_C_RESTRICT])
+  gl_SHA256
+  AC_DEFINE([GL_COMPILE_CRYPTO_STREAM], 1, [Compile Gnulib crypto stream ops.])
+  AC_REQUIRE([AC_C_RESTRICT])
+  gl_SHA512
+  gl_CTYPE_H
+  gl_CHECK_TYPE_STRUCT_DIRENT_D_INO
+  gl_DIRENT_H
+  gl_FUNC_DIRFD
+  if test $ac_cv_func_dirfd = no && test $gl_cv_func_dirfd_macro = no \
+     || test $REPLACE_DIRFD = 1; then
+    AC_LIBOBJ([dirfd])
+    gl_PREREQ_DIRFD
+  fi
+  gl_DIRENT_MODULE_INDICATOR([dirfd])
+  gl_MODULE_INDICATOR([dirname])
+  gl_DOUBLE_SLASH_ROOT
+  gl_FUNC_DUP
+  if test $REPLACE_DUP = 1; then
+    AC_LIBOBJ([dup])
+    gl_PREREQ_DUP
+  fi
+  gl_UNISTD_MODULE_INDICATOR([dup])
+  gl_FUNC_DUP2
+  if test $REPLACE_DUP2 = 1; then
+    AC_LIBOBJ([dup2])
+    gl_PREREQ_DUP2
+  fi
+  gl_UNISTD_MODULE_INDICATOR([dup2])
+  gl_ENVIRON
+  gl_UNISTD_MODULE_INDICATOR([environ])
+  gl_HEADER_ERRNO_H
+  gl_ERROR
+  if test $ac_cv_lib_error_at_line = no; then
+    AC_LIBOBJ([error])
+    gl_PREREQ_ERROR
+  fi
+  m4_ifdef([AM_XGETTEXT_OPTION],
+    [AM_][XGETTEXT_OPTION([--flag=error:3:c-format])
+     AM_][XGETTEXT_OPTION([--flag=error_at_line:5:c-format])])
+  AC_REQUIRE([gl_EXTERN_INLINE])
+  gl_FATAL_SIGNAL
+  gl_FUNC_FCHDIR
+  gl_UNISTD_MODULE_INDICATOR([fchdir])
+  gl_FUNC_FCNTL
+  if test $HAVE_FCNTL = 0 || test $REPLACE_FCNTL = 1; then
+    AC_LIBOBJ([fcntl])
+  fi
+  gl_FCNTL_MODULE_INDICATOR([fcntl])
+  gl_FCNTL_H
+  gl_MODULE_INDICATOR([fd-safer-flag])
+  gl_FUNC_FDOPENDIR
+  if test $HAVE_FDOPENDIR = 0 || test $REPLACE_FDOPENDIR = 1; then
+    AC_LIBOBJ([fdopendir])
+  fi
+  gl_DIRENT_MODULE_INDICATOR([fdopendir])
+  gl_MODULE_INDICATOR([fdopendir])
+  gl_FUNC_FFLUSH
+  if test $REPLACE_FFLUSH = 1; then
+    AC_LIBOBJ([fflush])
+    gl_PREREQ_FFLUSH
+  fi
+  gl_MODULE_INDICATOR([fflush])
+  gl_STDIO_MODULE_INDICATOR([fflush])
+  gl_FILE_NAME_CONCAT_LGPL
+  gl_FINDPROG_IN
+  AC_C_FLEXIBLE_ARRAY_MEMBER
+  gl_FLOAT_H
+  if test $REPLACE_FLOAT_LDBL = 1; then
+    AC_LIBOBJ([float])
+  fi
+  if test $REPLACE_ITOLD = 1; then
+    AC_LIBOBJ([itold])
+  fi
+  gl_FUNC_FLOCK
+  if test $HAVE_FLOCK = 0; then
+    AC_LIBOBJ([flock])
+    gl_PREREQ_FLOCK
+  fi
+  gl_HEADER_SYS_FILE_MODULE_INDICATOR([flock])
+  gl_FUNC_FNMATCH_POSIX
+  if test $HAVE_FNMATCH = 0 || test $REPLACE_FNMATCH = 1; then
+    AC_LIBOBJ([fnmatch])
+    gl_PREREQ_FNMATCH
+  fi
+  gl_FNMATCH_MODULE_INDICATOR([fnmatch])
+  gl_FUNC_FNMATCH_GNU
+  if test $HAVE_FNMATCH = 0 || test $REPLACE_FNMATCH = 1; then
+    AC_LIBOBJ([fnmatch])
+    gl_PREREQ_FNMATCH
+  fi
+  gl_MODULE_INDICATOR([fnmatch-gnu])
+  gl_FNMATCH_H
+  gl_FUNC_FOPEN
+  if test $REPLACE_FOPEN = 1; then
+    AC_LIBOBJ([fopen])
+    gl_PREREQ_FOPEN
+  fi
+  gl_STDIO_MODULE_INDICATOR([fopen])
+  gl_FUNC_FOPEN_GNU
+  if test $REPLACE_FOPEN = 1; then
+    AC_LIBOBJ([fopen])
+    gl_PREREQ_FOPEN
+  fi
+  gl_MODULE_INDICATOR([fopen-gnu])
+  gl_FUNC_FPURGE
+  if test $HAVE_FPURGE = 0 || test $REPLACE_FPURGE = 1; then
+    AC_LIBOBJ([fpurge])
+  fi
+  gl_STDIO_MODULE_INDICATOR([fpurge])
+  gl_FUNC_FREADING
+  gl_FUNC_FREE
+  if test $REPLACE_FREE = 1; then
+    AC_LIBOBJ([free])
+    gl_PREREQ_FREE
+  fi
+  gl_STDLIB_MODULE_INDICATOR([free-posix])
+  gl_FUNC_FSEEK
+  if test $REPLACE_FSEEK = 1; then
+    AC_LIBOBJ([fseek])
+  fi
+  gl_STDIO_MODULE_INDICATOR([fseek])
+  gl_FUNC_FSEEKO
+  if test $HAVE_FSEEKO = 0 || test $REPLACE_FSEEKO = 1; then
+    AC_LIBOBJ([fseeko])
+    gl_PREREQ_FSEEKO
+  fi
+  gl_STDIO_MODULE_INDICATOR([fseeko])
+  gl_FUNC_FSTAT
+  if test $REPLACE_FSTAT = 1; then
+    AC_LIBOBJ([fstat])
+    case "$host_os" in
+      mingw*)
+        AC_LIBOBJ([stat-w32])
+        ;;
+    esac
+    gl_PREREQ_FSTAT
+  fi
+  gl_SYS_STAT_MODULE_INDICATOR([fstat])
+  gl_FUNC_FSTATAT
+  if test $HAVE_FSTATAT = 0 || test $REPLACE_FSTATAT = 1; then
+    AC_LIBOBJ([fstatat])
+  fi
+  gl_SYS_STAT_MODULE_INDICATOR([fstatat])
+  gl_FUNC_FTELL
+  if test $REPLACE_FTELL = 1; then
+    AC_LIBOBJ([ftell])
+  fi
+  gl_STDIO_MODULE_INDICATOR([ftell])
+  gl_FUNC_FTELLO
+  if test $HAVE_FTELLO = 0 || test $REPLACE_FTELLO = 1; then
+    AC_LIBOBJ([ftello])
+    gl_PREREQ_FTELLO
+  fi
+  gl_STDIO_MODULE_INDICATOR([ftello])
+  gl_FUNC_FUTIMENS
+  if test $HAVE_FUTIMENS = 0 || test $REPLACE_FUTIMENS = 1; then
+    AC_LIBOBJ([futimens])
+  fi
+  gl_SYS_STAT_MODULE_INDICATOR([futimens])
+  gl_GETADDRINFO
+  if test $HAVE_GETADDRINFO = 0 || test $REPLACE_GETADDRINFO = 1; then
+    AC_LIBOBJ([getaddrinfo])
+  fi
+  if test $HAVE_DECL_GAI_STRERROR = 0 || test $REPLACE_GAI_STRERROR = 1; then
+    AC_LIBOBJ([gai_strerror])
+  fi
+  gl_NETDB_MODULE_INDICATOR([getaddrinfo])
+  gl_FUNC_GETCWD
+  if test $REPLACE_GETCWD = 1; then
+    AC_LIBOBJ([getcwd])
+    gl_PREREQ_GETCWD
+  fi
+  gl_MODULE_INDICATOR([getcwd])
+  gl_UNISTD_MODULE_INDICATOR([getcwd])
+  gl_FUNC_GETCWD_LGPL
+  if test $REPLACE_GETCWD = 1; then
+    AC_LIBOBJ([getcwd-lgpl])
+  fi
+  gl_UNISTD_MODULE_INDICATOR([getcwd])
+  gl_FUNC_GETDELIM
+  if test $HAVE_GETDELIM = 0 || test $REPLACE_GETDELIM = 1; then
+    AC_LIBOBJ([getdelim])
+    gl_PREREQ_GETDELIM
+  fi
+  gl_STDIO_MODULE_INDICATOR([getdelim])
+  gl_FUNC_GETDTABLESIZE
+  if test $HAVE_GETDTABLESIZE = 0 || test $REPLACE_GETDTABLESIZE = 1; then
+    AC_LIBOBJ([getdtablesize])
+    gl_PREREQ_GETDTABLESIZE
+  fi
+  gl_UNISTD_MODULE_INDICATOR([getdtablesize])
+  gl_FUNC_GETGROUPS
+  if test $HAVE_GETGROUPS = 0 || test $REPLACE_GETGROUPS = 1; then
+    AC_LIBOBJ([getgroups])
+  fi
+  gl_UNISTD_MODULE_INDICATOR([getgroups])
+  gl_FUNC_GETLINE
+  if test $REPLACE_GETLINE = 1; then
+    AC_LIBOBJ([getline])
+    gl_PREREQ_GETLINE
+  fi
+  gl_STDIO_MODULE_INDICATOR([getline])
+  gl_FUNC_GETOPT_GNU
+  dnl Because of the way gl_FUNC_GETOPT_GNU is implemented (the gl_getopt_required
+  dnl mechanism), there is no need to do any AC_LIBOBJ or AC_SUBST here; they are
+  dnl done in the getopt-posix module.
+  gl_FUNC_GETOPT_POSIX
+  if test $REPLACE_GETOPT = 1; then
+    AC_LIBOBJ([getopt])
+    AC_LIBOBJ([getopt1])
+    dnl Arrange for unistd.h to include getopt.h.
+    GNULIB_GL_UNISTD_H_GETOPT=1
+  fi
+  AC_SUBST([GNULIB_GL_UNISTD_H_GETOPT])
+  gl_UNISTD_MODULE_INDICATOR([getopt-posix])
+  gl_FUNC_GETPASS
+  if test $HAVE_GETPASS = 0 || test $REPLACE_GETPASS = 1; then
+    AC_LIBOBJ([getpass])
+    gl_PREREQ_GETPASS
+  fi
+  gl_UNISTD_MODULE_INDICATOR([getpass])
+  gl_FUNC_GETPASS_GNU
+  if test $HAVE_GETPASS = 0 || test $REPLACE_GETPASS = 1; then
+    AC_LIBOBJ([getpass])
+    gl_PREREQ_GETPASS
+  fi
+  gl_UNISTD_MODULE_INDICATOR([getpass])
+  AC_REQUIRE([gl_HEADER_SYS_SOCKET])
+  if test "$ac_cv_header_winsock2_h" = yes; then
+    AC_LIBOBJ([getpeername])
+  fi
+  gl_SYS_SOCKET_MODULE_INDICATOR([getpeername])
+  gl_FUNC_GETPROGNAME
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  gl_FUNC_GETRANDOM
+  if test $HAVE_GETRANDOM = 0 || test $REPLACE_GETRANDOM = 1; then
+    AC_LIBOBJ([getrandom])
+  fi
+  gl_SYS_RANDOM_MODULE_INDICATOR([getrandom])
+  AC_REQUIRE([gl_HEADER_SYS_SOCKET])
+  if test "$ac_cv_header_winsock2_h" = yes; then
+    AC_LIBOBJ([getsockname])
+  fi
+  gl_SYS_SOCKET_MODULE_INDICATOR([getsockname])
+  AC_SUBST([LIBINTL])
+  AC_SUBST([LTLIBINTL])
+  gl_GETTIME
+  gl_FUNC_GETTIMEOFDAY
+  if test $HAVE_GETTIMEOFDAY = 0 || test $REPLACE_GETTIMEOFDAY = 1; then
+    AC_LIBOBJ([gettimeofday])
+    gl_PREREQ_GETTIMEOFDAY
+  fi
+  gl_SYS_TIME_MODULE_INDICATOR([gettimeofday])
+  # Autoconf 2.61a.99 and earlier don't support linking a file only
+  # in VPATH builds.  But since GNUmakefile is for maintainer use
+  # only, it does not matter if we skip the link with older autoconf.
+  # Automake 1.10.1 and earlier try to remove GNUmakefile in non-VPATH
+  # builds, so use a shell variable to bypass this.
+  GNUmakefile=GNUmakefile
+  m4_if(m4_version_compare([2.61a.100],
+          m4_defn([m4_PACKAGE_VERSION])), [1], [],
+        [AC_CONFIG_LINKS([$GNUmakefile:$GNUmakefile], [],
+          [GNUmakefile=$GNUmakefile])])
+  gl_FUNC_GROUP_MEMBER
+  if test $HAVE_GROUP_MEMBER = 0; then
+    AC_LIBOBJ([group-member])
+    gl_PREREQ_GROUP_MEMBER
+  fi
+  gl_UNISTD_MODULE_INDICATOR([group-member])
+  AC_REQUIRE([gl_FUNC_SETLOCALE_NULL])
+  LIB_HARD_LOCALE="$LIB_SETLOCALE_NULL"
+  AC_SUBST([LIB_HARD_LOCALE])
+  AC_DEFUN([gl_HAVE_MODULE_HAVELIB])
+  gl_HOSTENT
+  AM_ICONV
+  m4_ifdef([gl_ICONV_MODULE_INDICATOR],
+    [gl_ICONV_MODULE_INDICATOR([iconv])])
+  gl_ICONV_H
+  gl_FUNC_INET_NTOP
+  if test $HAVE_INET_NTOP = 0 || test $REPLACE_INET_NTOP = 1; then
+    AC_LIBOBJ([inet_ntop])
+    gl_PREREQ_INET_NTOP
+  fi
+  gl_ARPA_INET_MODULE_INDICATOR([inet_ntop])
+  gl_INLINE
+  gl_INTTYPES_H
+  gl_INTTYPES_INCOMPLETE
+  gl_FUNC_IOCTL
+  if test $HAVE_IOCTL = 0 || test $REPLACE_IOCTL = 1; then
+    AC_LIBOBJ([ioctl])
+  fi
+  gl_SYS_IOCTL_MODULE_INDICATOR([ioctl])
+  gl_FUNC_ISBLANK
+  if test $HAVE_ISBLANK = 0; then
+    AC_LIBOBJ([isblank])
+  fi
+  gl_MODULE_INDICATOR([isblank])
+  gl_CTYPE_MODULE_INDICATOR([isblank])
+  gl_FUNC_ISWBLANK
+  if test $HAVE_ISWCNTRL = 0 || test $REPLACE_ISWCNTRL = 1; then
+    :
+  else
+    if test $HAVE_ISWBLANK = 0 || test $REPLACE_ISWBLANK = 1; then
+      AC_LIBOBJ([iswblank])
+    fi
+  fi
+  gl_WCTYPE_MODULE_INDICATOR([iswblank])
+  gl_FUNC_ISWDIGIT
+  if test $HAVE_ISWCNTRL = 0 || test $REPLACE_ISWCNTRL = 1; then
+    :
+  else
+    if test $REPLACE_ISWDIGIT = 1; then
+      AC_LIBOBJ([iswdigit])
+    fi
+  fi
+  gl_WCTYPE_MODULE_INDICATOR([iswdigit])
+  gl_FUNC_ISWXDIGIT
+  if test $HAVE_ISWCNTRL = 0 || test $REPLACE_ISWCNTRL = 1; then
+    :
+  else
+    if test $REPLACE_ISWXDIGIT = 1; then
+      AC_LIBOBJ([iswxdigit])
+    fi
+  fi
+  gl_WCTYPE_MODULE_INDICATOR([iswxdigit])
+  gl_LANGINFO_H
+  AC_REQUIRE([gl_LARGEFILE])
+  gl___INLINE
+  gl_LIBUNISTRING_OPTIONAL
+  gl_LIMITS_H
+  gl_FUNC_LINK
+  if test $HAVE_LINK = 0 || test $REPLACE_LINK = 1; then
+    AC_LIBOBJ([link])
+  fi
+  gl_UNISTD_MODULE_INDICATOR([link])
+  AC_REQUIRE([gl_HEADER_SYS_SOCKET])
+  if test "$ac_cv_header_winsock2_h" = yes; then
+    AC_LIBOBJ([listen])
+  fi
+  gl_SYS_SOCKET_MODULE_INDICATOR([listen])
+  gl_LOCALCHARSET
+  dnl For backward compatibility. Some packages still use this.
+  LOCALCHARSET_TESTS_ENVIRONMENT=
+  AC_SUBST([LOCALCHARSET_TESTS_ENVIRONMENT])
+  gl_LOCALE_H
+  gl_FUNC_LOCALECONV
+  if test $REPLACE_LOCALECONV = 1; then
+    AC_LIBOBJ([localeconv])
+    gl_PREREQ_LOCALECONV
+  fi
+  gl_LOCALE_MODULE_INDICATOR([localeconv])
+  gl_LOCK
+  gl_MODULE_INDICATOR([lock])
+  gl_FUNC_LSEEK
+  if test $REPLACE_LSEEK = 1; then
+    AC_LIBOBJ([lseek])
+  fi
+  gl_UNISTD_MODULE_INDICATOR([lseek])
+  gl_FUNC_LSTAT
+  if test $REPLACE_LSTAT = 1; then
+    AC_LIBOBJ([lstat])
+    gl_PREREQ_LSTAT
+  fi
+  gl_SYS_STAT_MODULE_INDICATOR([lstat])
+  AC_CONFIG_COMMANDS_PRE([m4_ifdef([AH_HEADER],
+    [AC_SUBST([CONFIG_INCLUDE], m4_defn([AH_HEADER]))])])
+  AC_REQUIRE([AC_PROG_SED])
+  AC_REQUIRE([AC_PROG_GREP])
+  gl_FUNC_MALLOC_POSIX
+  if test $REPLACE_MALLOC = 1; then
+    AC_LIBOBJ([malloc])
+  fi
+  gl_STDLIB_MODULE_INDICATOR([malloc-posix])
+  gl_MALLOCA
+  gl_MBCHAR
+  gl_MBITER
+  gl_FUNC_MBRTOWC
+  if test $HAVE_MBRTOWC = 0 || test $REPLACE_MBRTOWC = 1; then
+    AC_LIBOBJ([mbrtowc])
+    if test $REPLACE_MBSTATE_T = 1; then
+      AC_LIBOBJ([lc-charset-dispatch])
+      AC_LIBOBJ([mbtowc-lock])
+      gl_PREREQ_MBTOWC_LOCK
+    fi
+    gl_PREREQ_MBRTOWC
+  fi
+  gl_WCHAR_MODULE_INDICATOR([mbrtowc])
+  gl_FUNC_MBSINIT
+  if test $HAVE_MBSINIT = 0 || test $REPLACE_MBSINIT = 1; then
+    AC_LIBOBJ([mbsinit])
+    gl_PREREQ_MBSINIT
+  fi
+  gl_WCHAR_MODULE_INDICATOR([mbsinit])
+  gl_FUNC_MBSRTOWCS
+  if test $HAVE_MBSRTOWCS = 0 || test $REPLACE_MBSRTOWCS = 1; then
+    AC_LIBOBJ([mbsrtowcs])
+    AC_LIBOBJ([mbsrtowcs-state])
+    gl_PREREQ_MBSRTOWCS
+  fi
+  gl_WCHAR_MODULE_INDICATOR([mbsrtowcs])
+  gl_FUNC_MBTOWC
+  if test $HAVE_MBTOWC = 0 || test $REPLACE_MBTOWC = 1; then
+    AC_LIBOBJ([mbtowc])
+    gl_PREREQ_MBTOWC
+  fi
+  gl_STDLIB_MODULE_INDICATOR([mbtowc])
+  gl_FUNC_MEMCHR
+  if test $REPLACE_MEMCHR = 1; then
+    AC_LIBOBJ([memchr])
+    gl_PREREQ_MEMCHR
+  fi
+  gl_STRING_MODULE_INDICATOR([memchr])
+  gl_FUNC_MEMPCPY
+  if test $HAVE_MEMPCPY = 0; then
+    AC_LIBOBJ([mempcpy])
+    gl_PREREQ_MEMPCPY
+  fi
+  gl_STRING_MODULE_INDICATOR([mempcpy])
+  gl_FUNC_MEMRCHR
+  if test $ac_cv_func_memrchr = no; then
+    AC_LIBOBJ([memrchr])
+    gl_PREREQ_MEMRCHR
+  fi
+  gl_STRING_MODULE_INDICATOR([memrchr])
+  gl_MINMAX
+  gl_FUNC_MKDIR
+  if test $REPLACE_MKDIR = 1; then
+    AC_LIBOBJ([mkdir])
+  fi
+  gl_SYS_STAT_MODULE_INDICATOR([mkdir])
+  gl_FUNC_MKOSTEMP
+  if test $HAVE_MKOSTEMP = 0; then
+    AC_LIBOBJ([mkostemp])
+    gl_PREREQ_MKOSTEMP
+  fi
+  gl_MODULE_INDICATOR([mkostemp])
+  gl_STDLIB_MODULE_INDICATOR([mkostemp])
+  gl_FUNC_MKSTEMP
+  if test $HAVE_MKSTEMP = 0 || test $REPLACE_MKSTEMP = 1; then
+    AC_LIBOBJ([mkstemp])
+    gl_PREREQ_MKSTEMP
+  fi
+  gl_STDLIB_MODULE_INDICATOR([mkstemp])
+  gl_FUNC_MKTIME
+  if test $REPLACE_MKTIME = 1; then
+    AC_LIBOBJ([mktime])
+    gl_PREREQ_MKTIME
+  fi
+  gl_TIME_MODULE_INDICATOR([mktime])
+  gl_FUNC_MKTIME_INTERNAL
+  if test $WANT_MKTIME_INTERNAL = 1; then
+    AC_LIBOBJ([mktime])
+    gl_PREREQ_MKTIME
+  fi
+  AC_REQUIRE([gl_MSVC_INVAL])
+  if test $HAVE_MSVC_INVALID_PARAMETER_HANDLER = 1; then
+    AC_LIBOBJ([msvc-inval])
+  fi
+  AC_REQUIRE([gl_MSVC_NOTHROW])
+  if test $HAVE_MSVC_INVALID_PARAMETER_HANDLER = 1; then
+    AC_LIBOBJ([msvc-nothrow])
+  fi
+  gl_MODULE_INDICATOR([msvc-nothrow])
+  gl_MULTIARCH
+  gl_FUNC_NANOSLEEP
+  if test $HAVE_NANOSLEEP = 0 || test $REPLACE_NANOSLEEP = 1; then
+    AC_LIBOBJ([nanosleep])
+    gl_PREREQ_NANOSLEEP
+  fi
+  gl_TIME_MODULE_INDICATOR([nanosleep])
+  gl_HEADER_NETDB
+  gl_HEADER_NETINET_IN
+  AC_PROG_MKDIR_P
+  gl_FUNC_NL_LANGINFO
+  if test $HAVE_NL_LANGINFO = 0 || test $REPLACE_NL_LANGINFO = 1; then
+    AC_LIBOBJ([nl_langinfo])
+  fi
+  if test $REPLACE_NL_LANGINFO = 1 && test $NL_LANGINFO_MTSAFE = 0; then
+    AC_LIBOBJ([nl_langinfo-lock])
+    gl_PREREQ_NL_LANGINFO_LOCK
+  fi
+  gl_LANGINFO_MODULE_INDICATOR([nl_langinfo])
+  gl_FUNC_OPEN
+  if test $REPLACE_OPEN = 1; then
+    AC_LIBOBJ([open])
+    gl_PREREQ_OPEN
+  fi
+  gl_FCNTL_MODULE_INDICATOR([open])
+  gl_FUNC_OPENAT
+  if test $HAVE_OPENAT = 0 || test $REPLACE_OPENAT = 1; then
+    AC_LIBOBJ([openat])
+    gl_PREREQ_OPENAT
+  fi
+  gl_MODULE_INDICATOR([openat]) dnl for lib/getcwd.c
+  gl_FCNTL_MODULE_INDICATOR([openat])
+  gl_FUNC_OPENDIR
+  if test $HAVE_OPENDIR = 0 || test $REPLACE_OPENDIR = 1; then
+    AC_LIBOBJ([opendir])
+  fi
+  gl_DIRENT_MODULE_INDICATOR([opendir])
+  gl_PATHMAX
+  gl_FUNC_PIPE
+  if test $HAVE_PIPE = 0; then
+    AC_LIBOBJ([pipe])
+  fi
+  gl_UNISTD_MODULE_INDICATOR([pipe])
+  gl_FUNC_PIPE2
+  gl_UNISTD_MODULE_INDICATOR([pipe2])
+  gl_MODULE_INDICATOR([pipe2-safer])
+  gl_POSIX_SPAWN
+  if test $HAVE_POSIX_SPAWN = 0 || test $REPLACE_POSIX_SPAWN = 1; then
+    AC_LIBOBJ([spawn])
+  fi
+  gl_SPAWN_MODULE_INDICATOR([posix_spawn])
+  gl_POSIX_SPAWN
+  if test $HAVE_POSIX_SPAWN = 0 || test $REPLACE_POSIX_SPAWN = 1; then
+    AC_LIBOBJ([spawni])
+    gl_PREREQ_POSIX_SPAWN_INTERNAL
+  fi
+  gl_FUNC_POSIX_SPAWN_FILE_ACTIONS_ADDCHDIR
+  if test $HAVE_POSIX_SPAWN = 0 || test $REPLACE_POSIX_SPAWN = 1 || test $HAVE_POSIX_SPAWN_FILE_ACTIONS_ADDCHDIR = 0 || test $REPLACE_POSIX_SPAWN_FILE_ACTIONS_ADDCHDIR = 1; then
+    AC_LIBOBJ([spawn_faction_addchdir])
+  fi
+  gl_SPAWN_MODULE_INDICATOR([posix_spawn_file_actions_addchdir])
+  gl_FUNC_POSIX_SPAWN_FILE_ACTIONS_ADDCLOSE
+  if test $HAVE_POSIX_SPAWN = 0 || test $REPLACE_POSIX_SPAWN = 1 || test $REPLACE_POSIX_SPAWN_FILE_ACTIONS_ADDCLOSE = 1; then
+    AC_LIBOBJ([spawn_faction_addclose])
+  fi
+  gl_SPAWN_MODULE_INDICATOR([posix_spawn_file_actions_addclose])
+  gl_FUNC_POSIX_SPAWN_FILE_ACTIONS_ADDDUP2
+  if test $HAVE_POSIX_SPAWN = 0 || test $REPLACE_POSIX_SPAWN = 1 || test $REPLACE_POSIX_SPAWN_FILE_ACTIONS_ADDDUP2 = 1; then
+    AC_LIBOBJ([spawn_faction_adddup2])
+  fi
+  gl_SPAWN_MODULE_INDICATOR([posix_spawn_file_actions_adddup2])
+  gl_FUNC_POSIX_SPAWN_FILE_ACTIONS_ADDOPEN
+  if test $HAVE_POSIX_SPAWN = 0 || test $REPLACE_POSIX_SPAWN = 1 || test $REPLACE_POSIX_SPAWN_FILE_ACTIONS_ADDOPEN = 1; then
+    AC_LIBOBJ([spawn_faction_addopen])
+  fi
+  gl_SPAWN_MODULE_INDICATOR([posix_spawn_file_actions_addopen])
+  gl_POSIX_SPAWN
+  if test $HAVE_POSIX_SPAWN = 0 || test $REPLACE_POSIX_SPAWN = 1; then
+    AC_LIBOBJ([spawn_faction_destroy])
+  fi
+  gl_SPAWN_MODULE_INDICATOR([posix_spawn_file_actions_destroy])
+  gl_POSIX_SPAWN
+  if test $HAVE_POSIX_SPAWN = 0 || test $REPLACE_POSIX_SPAWN = 1; then
+    AC_LIBOBJ([spawn_faction_init])
+  fi
+  gl_SPAWN_MODULE_INDICATOR([posix_spawn_file_actions_init])
+  gl_POSIX_SPAWN
+  if test $HAVE_POSIX_SPAWN = 0 || test $REPLACE_POSIX_SPAWN = 1; then
+    AC_LIBOBJ([spawnattr_destroy])
+  fi
+  gl_SPAWN_MODULE_INDICATOR([posix_spawnattr_destroy])
+  gl_POSIX_SPAWN
+  if test $HAVE_POSIX_SPAWN = 0 || test $REPLACE_POSIX_SPAWN = 1; then
+    AC_LIBOBJ([spawnattr_init])
+  fi
+  gl_SPAWN_MODULE_INDICATOR([posix_spawnattr_init])
+  gl_POSIX_SPAWN
+  if test $HAVE_POSIX_SPAWN = 0 || test $REPLACE_POSIX_SPAWN = 1; then
+    AC_LIBOBJ([spawnattr_setflags])
+  fi
+  gl_SPAWN_MODULE_INDICATOR([posix_spawnattr_setflags])
+  gl_POSIX_SPAWN
+  if test $HAVE_POSIX_SPAWN = 0 || test $REPLACE_POSIX_SPAWN = 1; then
+    AC_LIBOBJ([spawnattr_setpgroup])
+  fi
+  gl_SPAWN_MODULE_INDICATOR([posix_spawnattr_setpgroup])
+  gl_POSIX_SPAWN
+  if test $HAVE_POSIX_SPAWN = 0 || test $REPLACE_POSIX_SPAWN = 1; then
+    AC_LIBOBJ([spawnattr_setsigmask])
+  fi
+  gl_SPAWN_MODULE_INDICATOR([posix_spawnattr_setsigmask])
+  gl_POSIX_SPAWN
+  if test $HAVE_POSIX_SPAWN = 0 || test $REPLACE_POSIX_SPAWN = 1; then
+    AC_LIBOBJ([spawnp])
+  fi
+  gl_SPAWN_MODULE_INDICATOR([posix_spawnp])
+  gl_QUOTE
+  gl_QUOTEARG
+  gl_FUNC_RAISE
+  if test $HAVE_RAISE = 0 || test $REPLACE_RAISE = 1; then
+    AC_LIBOBJ([raise])
+    gl_PREREQ_RAISE
+  fi
+  gl_SIGNAL_MODULE_INDICATOR([raise])
+  gl_FUNC_RAWMEMCHR
+  if test $HAVE_RAWMEMCHR = 0; then
+    AC_LIBOBJ([rawmemchr])
+    gl_PREREQ_RAWMEMCHR
+  fi
+  gl_STRING_MODULE_INDICATOR([rawmemchr])
+  gl_FUNC_READDIR
+  if test $HAVE_READDIR = 0; then
+    AC_LIBOBJ([readdir])
+  fi
+  gl_DIRENT_MODULE_INDICATOR([readdir])
+  gl_FUNC_READLINK
+  if test $HAVE_READLINK = 0 || test $REPLACE_READLINK = 1; then
+    AC_LIBOBJ([readlink])
+    gl_PREREQ_READLINK
+  fi
+  gl_UNISTD_MODULE_INDICATOR([readlink])
+  gl_FUNC_REALLOC_POSIX
+  if test $REPLACE_REALLOC = 1; then
+    AC_LIBOBJ([realloc])
+  fi
+  gl_STDLIB_MODULE_INDICATOR([realloc-posix])
+  AC_REQUIRE([gl_HEADER_SYS_SOCKET])
+  if test "$ac_cv_header_winsock2_h" = yes; then
+    AC_LIBOBJ([recv])
+  fi
+  gl_SYS_SOCKET_MODULE_INDICATOR([recv])
+  gl_REGEX
+  if test $ac_use_included_regex = yes; then
+    AC_LIBOBJ([regex])
+    gl_PREREQ_REGEX
+  fi
+  gl_FUNC_REWINDDIR
+  if test $HAVE_REWINDDIR = 0; then
+    AC_LIBOBJ([rewinddir])
+  fi
+  gl_DIRENT_MODULE_INDICATOR([rewinddir])
+  gl_SAVE_CWD
+  gl_SCHED_H
+  gl_FUNC_SECURE_GETENV
+  if test $HAVE_SECURE_GETENV = 0; then
+    AC_LIBOBJ([secure_getenv])
+    gl_PREREQ_SECURE_GETENV
+  fi
+  gl_STDLIB_MODULE_INDICATOR([secure_getenv])
+  gl_FUNC_SELECT
+  if test $REPLACE_SELECT = 1; then
+    AC_LIBOBJ([select])
+  fi
+  gl_SYS_SELECT_MODULE_INDICATOR([select])
+  AC_REQUIRE([gl_HEADER_SYS_SOCKET])
+  if test "$ac_cv_header_winsock2_h" = yes; then
+    AC_LIBOBJ([send])
+  fi
+  gl_SYS_SOCKET_MODULE_INDICATOR([send])
+  gl_SERVENT
+  gl_FUNC_SETLOCALE_NULL
+  if test $SETLOCALE_NULL_ALL_MTSAFE = 0 || test $SETLOCALE_NULL_ONE_MTSAFE = 0; then
+    AC_LIBOBJ([setlocale-lock])
+    gl_PREREQ_SETLOCALE_LOCK
+  fi
+  gl_LOCALE_MODULE_INDICATOR([setlocale_null])
+  AC_REQUIRE([gl_HEADER_SYS_SOCKET])
+  if test "$ac_cv_header_winsock2_h" = yes; then
+    AC_LIBOBJ([setsockopt])
+  fi
+  gl_SYS_SOCKET_MODULE_INDICATOR([setsockopt])
+  gl_SH_FILENAME
+  gl_SIGACTION
+  if test $HAVE_SIGACTION = 0; then
+    AC_LIBOBJ([sigaction])
+    gl_PREREQ_SIGACTION
+  fi
+  gl_SIGNAL_MODULE_INDICATOR([sigaction])
+  gl_SIGNAL_H
+  gl_SIGNAL_SIGPIPE
+  dnl Define the C macro GNULIB_SIGPIPE to 1.
+  gl_MODULE_INDICATOR([sigpipe])
+  dnl Define the substituted variable GNULIB_SIGNAL_H_SIGPIPE to 1.
+  AC_REQUIRE([gl_SIGNAL_H_DEFAULTS])
+  GNULIB_SIGNAL_H_SIGPIPE=1
+  dnl Define the substituted variable GNULIB_STDIO_H_SIGPIPE to 1.
+  AC_REQUIRE([gl_STDIO_H_DEFAULTS])
+  AC_REQUIRE([gl_ASM_SYMBOL_PREFIX])
+  GNULIB_STDIO_H_SIGPIPE=1
+  dnl Define the substituted variable GNULIB_UNISTD_H_SIGPIPE to 1.
+  AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
+  GNULIB_UNISTD_H_SIGPIPE=1
+  gl_SIGNALBLOCKING
+  if test $HAVE_POSIX_SIGNALBLOCKING = 0; then
+    AC_LIBOBJ([sigprocmask])
+    gl_PREREQ_SIGPROCMASK
+  fi
+  gl_SIGNAL_MODULE_INDICATOR([sigprocmask])
+  gl_SIZE_MAX
+  gl_FUNC_SNPRINTF
+  gl_STDIO_MODULE_INDICATOR([snprintf])
+  gl_MODULE_INDICATOR([snprintf])
+  AC_REQUIRE([gl_HEADER_SYS_SOCKET])
+  if test "$ac_cv_header_winsock2_h" = yes; then
+    AC_LIBOBJ([socket])
+  fi
+  # When this module is used, sockets may actually occur as file descriptors,
+  # hence it is worth warning if the modules 'close' and 'ioctl' are not used.
+  m4_ifdef([gl_UNISTD_H_DEFAULTS], [AC_REQUIRE([gl_UNISTD_H_DEFAULTS])])
+  m4_ifdef([gl_SYS_IOCTL_H_DEFAULTS], [AC_REQUIRE([gl_SYS_IOCTL_H_DEFAULTS])])
+  AC_REQUIRE([gl_PREREQ_SYS_H_WINSOCK2])
+  if test "$ac_cv_header_winsock2_h" = yes; then
+    UNISTD_H_HAVE_WINSOCK2_H_AND_USE_SOCKETS=1
+    SYS_IOCTL_H_HAVE_WINSOCK2_H_AND_USE_SOCKETS=1
+  fi
+  gl_SYS_SOCKET_MODULE_INDICATOR([socket])
+  AC_REQUIRE([gl_SOCKETLIB])
+  AC_REQUIRE([gl_SOCKETS])
+  gl_TYPE_SOCKLEN_T
+  gl_SPAWN_H
+  gl_SPAWN_PIPE
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  case "$host_os" in
+    os2*)
+      AC_LIBOBJ([os2-spawn])
+      ;;
+  esac
+  gt_TYPE_SSIZE_T
+  gl_FUNC_STAT
+  if test $REPLACE_STAT = 1; then
+    AC_LIBOBJ([stat])
+    case "$host_os" in
+      mingw*)
+        AC_LIBOBJ([stat-w32])
+        ;;
+    esac
+    gl_PREREQ_STAT
+  fi
+  gl_SYS_STAT_MODULE_INDICATOR([stat])
+  gl_STAT_TIME
+  gl_STAT_BIRTHTIME
+  gl_STDALIGN_H
+  AM_STDBOOL_H
+  gl_STDDEF_H
+  gl_STDINT_H
+  gl_STDIO_H
+  gl_STDLIB_H
+  gl_FUNC_STPCPY
+  if test $HAVE_STPCPY = 0; then
+    AC_LIBOBJ([stpcpy])
+    gl_PREREQ_STPCPY
+  fi
+  gl_STRING_MODULE_INDICATOR([stpcpy])
+  gl_STRCASE
+  if test $HAVE_STRCASECMP = 0; then
+    AC_LIBOBJ([strcasecmp])
+    gl_PREREQ_STRCASECMP
+  fi
+  if test $HAVE_STRNCASECMP = 0; then
+    AC_LIBOBJ([strncasecmp])
+    gl_PREREQ_STRNCASECMP
+  fi
+  gl_FUNC_STRCHRNUL
+  if test $HAVE_STRCHRNUL = 0 || test $REPLACE_STRCHRNUL = 1; then
+    AC_LIBOBJ([strchrnul])
+    gl_PREREQ_STRCHRNUL
+  fi
+  gl_STRING_MODULE_INDICATOR([strchrnul])
+  gl_FUNC_STRDUP_POSIX
+  if test $REPLACE_STRDUP = 1; then
+    AC_LIBOBJ([strdup])
+    gl_PREREQ_STRDUP
+  fi
+  gl_STRING_MODULE_INDICATOR([strdup])
+  gl_FUNC_STRERROR
+  if test $REPLACE_STRERROR = 1; then
+    AC_LIBOBJ([strerror])
+  fi
+  gl_MODULE_INDICATOR([strerror])
+  gl_STRING_MODULE_INDICATOR([strerror])
+  AC_REQUIRE([gl_HEADER_ERRNO_H])
+  AC_REQUIRE([gl_FUNC_STRERROR_0])
+  if test -n "$ERRNO_H" || test $REPLACE_STRERROR_0 = 1; then
+    AC_LIBOBJ([strerror-override])
+    gl_PREREQ_SYS_H_WINSOCK2
+  fi
+  gl_FUNC_STRERROR_R
+  if test $HAVE_DECL_STRERROR_R = 0 || test $REPLACE_STRERROR_R = 1; then
+    AC_LIBOBJ([strerror_r])
+    gl_PREREQ_STRERROR_R
+  fi
+  gl_STRING_MODULE_INDICATOR([strerror_r])
+  dnl For the modules argp, error.
+  gl_MODULE_INDICATOR([strerror_r-posix])
+  gl_HEADER_STRING_H
+  gl_HEADER_STRINGS_H
+  gl_FUNC_STRNDUP
+  if test $HAVE_STRNDUP = 0 || test $REPLACE_STRNDUP = 1; then
+    AC_LIBOBJ([strndup])
+  fi
+  gl_STRING_MODULE_INDICATOR([strndup])
+  gl_FUNC_STRNLEN
+  if test $HAVE_DECL_STRNLEN = 0 || test $REPLACE_STRNLEN = 1; then
+    AC_LIBOBJ([strnlen])
+    gl_PREREQ_STRNLEN
+  fi
+  gl_STRING_MODULE_INDICATOR([strnlen])
+  gl_FUNC_STRPBRK
+  if test $HAVE_STRPBRK = 0; then
+    AC_LIBOBJ([strpbrk])
+    gl_PREREQ_STRPBRK
+  fi
+  gl_STRING_MODULE_INDICATOR([strpbrk])
+  gl_FUNC_STRPTIME
+  if test $HAVE_STRPTIME = 0; then
+    AC_LIBOBJ([strptime])
+    gl_PREREQ_STRPTIME
+  fi
+  gl_TIME_MODULE_INDICATOR([strptime])
+  gl_FUNC_STRTOK_R
+  if test $HAVE_STRTOK_R = 0 || test $REPLACE_STRTOK_R = 1; then
+    AC_LIBOBJ([strtok_r])
+    gl_PREREQ_STRTOK_R
+  fi
+  gl_STRING_MODULE_INDICATOR([strtok_r])
+  gl_FUNC_STRTOL
+  if test $ac_cv_func_strtol = no; then
+    AC_LIBOBJ([strtol])
+  fi
+  gl_FUNC_STRTOLL
+  if test $HAVE_STRTOLL = 0; then
+    AC_LIBOBJ([strtoll])
+    gl_PREREQ_STRTOLL
+  fi
+  gl_STDLIB_MODULE_INDICATOR([strtoll])
+  gl_FUNC_SYMLINK
+  if test $HAVE_SYMLINK = 0 || test $REPLACE_SYMLINK = 1; then
+    AC_LIBOBJ([symlink])
+  fi
+  gl_UNISTD_MODULE_INDICATOR([symlink])
+  gl_HEADER_SYS_FILE_H
+  AC_PROG_MKDIR_P
+  gl_SYS_IOCTL_H
+  AC_PROG_MKDIR_P
+  gl_HEADER_SYS_RANDOM
+  AC_PROG_MKDIR_P
+  AC_REQUIRE([gl_HEADER_SYS_SELECT])
+  AC_PROG_MKDIR_P
+  AC_REQUIRE([gl_HEADER_SYS_SOCKET])
+  AC_PROG_MKDIR_P
+  gl_HEADER_SYS_STAT_H
+  AC_PROG_MKDIR_P
+  gl_HEADER_SYS_TIME_H
+  AC_PROG_MKDIR_P
+  gl_SYS_TYPES_H
+  AC_PROG_MKDIR_P
+  gl_HEADER_SYS_UIO
+  AC_PROG_MKDIR_P
+  gl_SYS_WAIT_H
+  AC_PROG_MKDIR_P
+  gl_FUNC_GEN_TEMPNAME
+  gl_MODULE_INDICATOR([tempname])
+  AC_CHECK_HEADERS([sys/single_threaded.h])
+  AC_REQUIRE([gl_THREADLIB])
+  gl_HEADER_TIME_H
+  gl_TIME_R
+  if test $HAVE_LOCALTIME_R = 0 || test $REPLACE_LOCALTIME_R = 1; then
+    AC_LIBOBJ([time_r])
+    gl_PREREQ_TIME_R
+  fi
+  gl_TIME_MODULE_INDICATOR([time_r])
+  gl_FUNC_TIMEGM
+  if test $HAVE_TIMEGM = 0 || test $REPLACE_TIMEGM = 1; then
+    AC_LIBOBJ([timegm])
+    gl_PREREQ_TIMEGM
+  fi
+  gl_TIME_MODULE_INDICATOR([timegm])
+  gl_TIMESPEC
+  gt_TMPDIR
+  gl_LIBUNISTRING_LIBHEADER([0.9.4], [unicase.h])
+  AC_REQUIRE([AC_C_INLINE])
+  gl_LIBUNISTRING_MODULE([0.9.1], [unicase/empty-prefix-context])
+  gl_LIBUNISTRING_MODULE([0.9.1], [unicase/empty-suffix-context])
+  AC_REQUIRE([AC_C_INLINE])
+  gl_LIBUNISTRING_MODULE([0.9.8], [unicase/tolower])
+  gl_LIBUNISTRING_MODULE([0.9.8], [unicase/u8-tolower])
+  gl_LIBUNISTRING_LIBHEADER([0.9.4], [unictype.h])
+  gl_LIBUNISTRING_MODULE([0.9.8], [unictype/combining-class])
+  AC_REQUIRE([AC_C_INLINE])
+  gl_LIBUNISTRING_MODULE([0.9.8], [unictype/property-soft-dotted])
+  gl_LIBUNISTRING_LIBHEADER([0.9.4], [uninorm.h])
+  gl_MODULE_INDICATOR_FOR_TESTS([uninorm/u8-normalize])
+  gl_LIBUNISTRING_MODULE([0.9.8], [uninorm/u8-normalize])
+  gl_UNISTD_H
+  gl_UNISTD_SAFER
+  gl_LIBUNISTRING_LIBHEADER([0.9.4], [unistr.h])
+  gl_LIBUNISTRING_MODULE([0.9], [unistr/u8-cpy])
+  gl_MODULE_INDICATOR([unistr/u8-mbtouc-unsafe])
+  gl_LIBUNISTRING_MODULE([0.9.4], [unistr/u8-mbtouc-unsafe])
+  gl_LIBUNISTRING_MODULE([0.9], [unistr/u8-strlen])
+  gl_MODULE_INDICATOR([unistr/u8-uctomb])
+  gl_LIBUNISTRING_MODULE([0.9], [unistr/u8-uctomb])
+  gl_LIBUNISTRING_LIBHEADER([0.9.4], [unitypes.h])
+  gl_LIBUNISTRING_LIBHEADER([0.9.4], [uniwidth.h])
+  gl_LIBUNISTRING_MODULE([0.9.8], [uniwidth/width])
+  gl_FUNC_UNLINK
+  if test $REPLACE_UNLINK = 1; then
+    AC_LIBOBJ([unlink])
+  fi
+  gl_UNISTD_MODULE_INDICATOR([unlink])
+  gl_FUNC_GLIBC_UNLOCKED_IO
+  gl_FUNC_UTIME
+  if test $HAVE_UTIME = 0 || test $REPLACE_UTIME = 1; then
+    AC_LIBOBJ([utime])
+    gl_PREREQ_UTIME
+  fi
+  gl_UTIME_MODULE_INDICATOR([utime])
+  gl_UTIME_H
+  gl_UTIMENS
+  AC_REQUIRE([AC_C_RESTRICT])
+  gl_FUNC_VASNPRINTF
+  gl_FUNC_VASPRINTF
+  gl_STDIO_MODULE_INDICATOR([vasprintf])
+  m4_ifdef([AM_XGETTEXT_OPTION],
+    [AM_][XGETTEXT_OPTION([--flag=asprintf:2:c-format])
+     AM_][XGETTEXT_OPTION([--flag=vasprintf:2:c-format])])
+  gl_FUNC_VSNPRINTF
+  gl_STDIO_MODULE_INDICATOR([vsnprintf])
+  gl_WAIT_PROCESS
+  gl_FUNC_WAITPID
+  if test $HAVE_WAITPID = 0; then
+    AC_LIBOBJ([waitpid])
+  fi
+  gl_SYS_WAIT_MODULE_INDICATOR([waitpid])
+  gl_WCHAR_H
+  gl_FUNC_WCRTOMB
+  if test $HAVE_WCRTOMB = 0 || test $REPLACE_WCRTOMB = 1; then
+    AC_LIBOBJ([wcrtomb])
+    gl_PREREQ_WCRTOMB
+  fi
+  gl_WCHAR_MODULE_INDICATOR([wcrtomb])
+  gl_WCTYPE_H
+  gl_FUNC_WCWIDTH
+  if test $HAVE_WCWIDTH = 0 || test $REPLACE_WCWIDTH = 1; then
+    AC_LIBOBJ([wcwidth])
+    gl_PREREQ_WCWIDTH
+  fi
+  gl_WCHAR_MODULE_INDICATOR([wcwidth])
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  case "$host_os" in
+    mingw*)
+      AC_LIBOBJ([windows-mutex])
+      ;;
+  esac
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  case "$host_os" in
+    mingw*)
+      AC_LIBOBJ([windows-once])
+      ;;
+  esac
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  case "$host_os" in
+    mingw*)
+      AC_LIBOBJ([windows-recmutex])
+      ;;
+  esac
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  case "$host_os" in
+    mingw*)
+      AC_LIBOBJ([windows-rwlock])
+      ;;
+  esac
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  case "$host_os" in
+    mingw*)
+      AC_LIBOBJ([windows-spawn])
+      ;;
+  esac
+  gl_FUNC_WMEMCHR
+  if test $HAVE_WMEMCHR = 0; then
+    AC_LIBOBJ([wmemchr])
+  fi
+  gl_WCHAR_MODULE_INDICATOR([wmemchr])
+  gl_FUNC_WMEMPCPY
+  if test $HAVE_WMEMPCPY = 0; then
+    AC_LIBOBJ([wmempcpy])
+  fi
+  gl_WCHAR_MODULE_INDICATOR([wmempcpy])
+  gl_FUNC_WRITE
+  if test $REPLACE_WRITE = 1; then
+    AC_LIBOBJ([write])
+    gl_PREREQ_WRITE
+  fi
+  gl_UNISTD_MODULE_INDICATOR([write])
+  gl_XALLOC
+  gl_MODULE_INDICATOR([xalloc])
+  gl_MODULE_INDICATOR([xalloc-die])
+  gl_XSIZE
+  gl_XSTRNDUP
+  # End of code from modules
+  m4_ifval(gl_LIBSOURCES_LIST, [
+    m4_syscmd([test ! -d ]m4_defn([gl_LIBSOURCES_DIR])[ ||
+      for gl_file in ]gl_LIBSOURCES_LIST[ ; do
+        if test ! -r ]m4_defn([gl_LIBSOURCES_DIR])[/$gl_file ; then
+          echo "missing file ]m4_defn([gl_LIBSOURCES_DIR])[/$gl_file" >&2
+          exit 1
+        fi
+      done])dnl
+      m4_if(m4_sysval, [0], [],
+        [AC_FATAL([expected source file, required through AC_LIBSOURCES, not found])])
+  ])
+  m4_popdef([gl_LIBSOURCES_DIR])
+  m4_popdef([gl_LIBSOURCES_LIST])
+  m4_popdef([AC_LIBSOURCES])
+  m4_popdef([AC_REPLACE_FUNCS])
+  m4_popdef([AC_LIBOBJ])
+  AC_CONFIG_COMMANDS_PRE([
+    gl_libobjs=
+    gl_ltlibobjs=
+    if test -n "$gl_LIBOBJS"; then
+      # Remove the extension.
+      sed_drop_objext='s/\.o$//;s/\.obj$//'
+      for i in `for i in $gl_LIBOBJS; do echo "$i"; done | sed -e "$sed_drop_objext" | sort | uniq`; do
+        gl_libobjs="$gl_libobjs $i.$ac_objext"
+        gl_ltlibobjs="$gl_ltlibobjs $i.lo"
+      done
+    fi
+    AC_SUBST([gl_LIBOBJS], [$gl_libobjs])
+    AC_SUBST([gl_LTLIBOBJS], [$gl_ltlibobjs])
+  ])
+  gltests_libdeps=
+  gltests_ltlibdeps=
+  m4_pushdef([AC_LIBOBJ], m4_defn([gltests_LIBOBJ]))
+  m4_pushdef([AC_REPLACE_FUNCS], m4_defn([gltests_REPLACE_FUNCS]))
+  m4_pushdef([AC_LIBSOURCES], m4_defn([gltests_LIBSOURCES]))
+  m4_pushdef([gltests_LIBSOURCES_LIST], [])
+  m4_pushdef([gltests_LIBSOURCES_DIR], [])
+  gl_COMMON
+  gl_source_base='lib/tests'
+changequote(,)dnl
+  gltests_WITNESS=IN_`echo "${PACKAGE-$PACKAGE_TARNAME}" | LC_ALL=C tr abcdefghijklmnopqrstuvwxyz ABCDEFGHIJKLMNOPQRSTUVWXYZ | LC_ALL=C sed -e 's/[^A-Z0-9_]/_/g'`_GNULIB_TESTS
+changequote([, ])dnl
+  AC_SUBST([gltests_WITNESS])
+  gl_module_indicator_condition=$gltests_WITNESS
+  m4_pushdef([gl_MODULE_INDICATOR_CONDITION], [$gl_module_indicator_condition])
+  m4_popdef([gl_MODULE_INDICATOR_CONDITION])
+  m4_ifval(gltests_LIBSOURCES_LIST, [
+    m4_syscmd([test ! -d ]m4_defn([gltests_LIBSOURCES_DIR])[ ||
+      for gl_file in ]gltests_LIBSOURCES_LIST[ ; do
+        if test ! -r ]m4_defn([gltests_LIBSOURCES_DIR])[/$gl_file ; then
+          echo "missing file ]m4_defn([gltests_LIBSOURCES_DIR])[/$gl_file" >&2
+          exit 1
+        fi
+      done])dnl
+      m4_if(m4_sysval, [0], [],
+        [AC_FATAL([expected source file, required through AC_LIBSOURCES, not found])])
+  ])
+  m4_popdef([gltests_LIBSOURCES_DIR])
+  m4_popdef([gltests_LIBSOURCES_LIST])
+  m4_popdef([AC_LIBSOURCES])
+  m4_popdef([AC_REPLACE_FUNCS])
+  m4_popdef([AC_LIBOBJ])
+  AC_CONFIG_COMMANDS_PRE([
+    gltests_libobjs=
+    gltests_ltlibobjs=
+    if test -n "$gltests_LIBOBJS"; then
+      # Remove the extension.
+      sed_drop_objext='s/\.o$//;s/\.obj$//'
+      for i in `for i in $gltests_LIBOBJS; do echo "$i"; done | sed -e "$sed_drop_objext" | sort | uniq`; do
+        gltests_libobjs="$gltests_libobjs $i.$ac_objext"
+        gltests_ltlibobjs="$gltests_ltlibobjs $i.lo"
+      done
+    fi
+    AC_SUBST([gltests_LIBOBJS], [$gltests_libobjs])
+    AC_SUBST([gltests_LTLIBOBJS], [$gltests_ltlibobjs])
+  ])
+  LIBGNU_LIBDEPS="$gl_libdeps"
+  AC_SUBST([LIBGNU_LIBDEPS])
+  LIBGNU_LTLIBDEPS="$gl_ltlibdeps"
+  AC_SUBST([LIBGNU_LTLIBDEPS])
+])
+
+# Like AC_LIBOBJ, except that the module name goes
+# into gl_LIBOBJS instead of into LIBOBJS.
+AC_DEFUN([gl_LIBOBJ], [
+  AS_LITERAL_IF([$1], [gl_LIBSOURCES([$1.c])])dnl
+  gl_LIBOBJS="$gl_LIBOBJS $1.$ac_objext"
+])
+
+# Like AC_REPLACE_FUNCS, except that the module name goes
+# into gl_LIBOBJS instead of into LIBOBJS.
+AC_DEFUN([gl_REPLACE_FUNCS], [
+  m4_foreach_w([gl_NAME], [$1], [AC_LIBSOURCES(gl_NAME[.c])])dnl
+  AC_CHECK_FUNCS([$1], , [gl_LIBOBJ($ac_func)])
+])
+
+# Like AC_LIBSOURCES, except the directory where the source file is
+# expected is derived from the gnulib-tool parameterization,
+# and alloca is special cased (for the alloca-opt module).
+# We could also entirely rely on EXTRA_lib..._SOURCES.
+AC_DEFUN([gl_LIBSOURCES], [
+  m4_foreach([_gl_NAME], [$1], [
+    m4_if(_gl_NAME, [alloca.c], [], [
+      m4_define([gl_LIBSOURCES_DIR], [lib])
+      m4_append([gl_LIBSOURCES_LIST], _gl_NAME, [ ])
+    ])
+  ])
+])
+
+# Like AC_LIBOBJ, except that the module name goes
+# into gltests_LIBOBJS instead of into LIBOBJS.
+AC_DEFUN([gltests_LIBOBJ], [
+  AS_LITERAL_IF([$1], [gltests_LIBSOURCES([$1.c])])dnl
+  gltests_LIBOBJS="$gltests_LIBOBJS $1.$ac_objext"
+])
+
+# Like AC_REPLACE_FUNCS, except that the module name goes
+# into gltests_LIBOBJS instead of into LIBOBJS.
+AC_DEFUN([gltests_REPLACE_FUNCS], [
+  m4_foreach_w([gl_NAME], [$1], [AC_LIBSOURCES(gl_NAME[.c])])dnl
+  AC_CHECK_FUNCS([$1], , [gltests_LIBOBJ($ac_func)])
+])
+
+# Like AC_LIBSOURCES, except the directory where the source file is
+# expected is derived from the gnulib-tool parameterization,
+# and alloca is special cased (for the alloca-opt module).
+# We could also entirely rely on EXTRA_lib..._SOURCES.
+AC_DEFUN([gltests_LIBSOURCES], [
+  m4_foreach([_gl_NAME], [$1], [
+    m4_if(_gl_NAME, [alloca.c], [], [
+      m4_define([gltests_LIBSOURCES_DIR], [lib/tests])
+      m4_append([gltests_LIBSOURCES_LIST], _gl_NAME, [ ])
+    ])
+  ])
+])
+
+# This macro records the list of files which have been installed by
+# gnulib-tool and may be removed by future gnulib-tool invocations.
+AC_DEFUN([gl_FILE_LIST], [
+  build-aux/announce-gen
+  build-aux/config.rpath
+  build-aux/git-version-gen
+  build-aux/gitlog-to-changelog
+  build-aux/gnupload
+  build-aux/update-copyright
+  build-aux/useless-if-before-free
+  build-aux/vc-list-files
+  lib/_Noreturn.h
+  lib/accept.c
+  lib/access.c
+  lib/af_alg.c
+  lib/af_alg.h
+  lib/alloca.c
+  lib/alloca.in.h
+  lib/arg-nonnull.h
+  lib/arpa_inet.in.h
+  lib/array-mergesort.h
+  lib/asnprintf.c
+  lib/asprintf.c
+  lib/assure.h
+  lib/at-func.c
+  lib/attribute.h
+  lib/base32.c
+  lib/base32.h
+  lib/basename-lgpl.c
+  lib/basename-lgpl.h
+  lib/basename.c
+  lib/binary-io.c
+  lib/binary-io.h
+  lib/bind.c
+  lib/bitrotate.c
+  lib/bitrotate.h
+  lib/btowc.c
+  lib/byteswap.in.h
+  lib/c++defs.h
+  lib/c-ctype.c
+  lib/c-ctype.h
+  lib/c-strcase.h
+  lib/c-strcasecmp.c
+  lib/c-strcaseeq.h
+  lib/c-strcasestr.c
+  lib/c-strcasestr.h
+  lib/c-strncasecmp.c
+  lib/canonicalize.c
+  lib/canonicalize.h
+  lib/cdefs.h
+  lib/chdir-long.c
+  lib/chdir-long.h
+  lib/cloexec.c
+  lib/cloexec.h
+  lib/close.c
+  lib/closedir.c
+  lib/concat-filename.c
+  lib/concat-filename.h
+  lib/connect.c
+  lib/ctype.in.h
+  lib/dirent-private.h
+  lib/dirent.in.h
+  lib/dirfd.c
+  lib/dirname-lgpl.c
+  lib/dirname.c
+  lib/dirname.h
+  lib/dup-safer-flag.c
+  lib/dup-safer.c
+  lib/dup.c
+  lib/dup2.c
+  lib/errno.in.h
+  lib/error.c
+  lib/error.h
+  lib/exitfail.c
+  lib/exitfail.h
+  lib/fatal-signal.c
+  lib/fatal-signal.h
+  lib/fchdir.c
+  lib/fcntl.c
+  lib/fcntl.in.h
+  lib/fd-hook.c
+  lib/fd-hook.h
+  lib/fd-safer-flag.c
+  lib/fd-safer.c
+  lib/fdopendir.c
+  lib/fflush.c
+  lib/file-set.c
+  lib/file-set.h
+  lib/filename.h
+  lib/filenamecat-lgpl.c
+  lib/filenamecat.h
+  lib/findprog-in.c
+  lib/findprog.h
+  lib/flexmember.h
+  lib/float+.h
+  lib/float.c
+  lib/float.in.h
+  lib/flock.c
+  lib/fnmatch.c
+  lib/fnmatch.in.h
+  lib/fnmatch_loop.c
+  lib/fopen.c
+  lib/fpurge.c
+  lib/freading.c
+  lib/freading.h
+  lib/free.c
+  lib/fseek.c
+  lib/fseeko.c
+  lib/fstat.c
+  lib/fstatat.c
+  lib/ftell.c
+  lib/ftello.c
+  lib/futimens.c
+  lib/gai_strerror.c
+  lib/getaddrinfo.c
+  lib/getcwd-lgpl.c
+  lib/getcwd.c
+  lib/getdelim.c
+  lib/getdtablesize.c
+  lib/getgroups.c
+  lib/getline.c
+  lib/getopt-cdefs.in.h
+  lib/getopt-core.h
+  lib/getopt-ext.h
+  lib/getopt-pfx-core.h
+  lib/getopt-pfx-ext.h
+  lib/getopt.c
+  lib/getopt.in.h
+  lib/getopt1.c
+  lib/getopt_int.h
+  lib/getpass.c
+  lib/getpass.h
+  lib/getpeername.c
+  lib/getprogname.c
+  lib/getprogname.h
+  lib/getrandom.c
+  lib/getsockname.c
+  lib/gettext.h
+  lib/gettime.c
+  lib/gettimeofday.c
+  lib/gl_openssl.h
+  lib/glthread/lock.c
+  lib/glthread/lock.h
+  lib/glthread/threadlib.c
+  lib/group-member.c
+  lib/hard-locale.c
+  lib/hard-locale.h
+  lib/hash-pjw.c
+  lib/hash-pjw.h
+  lib/hash-triple-simple.c
+  lib/hash-triple.h
+  lib/hash.c
+  lib/hash.h
+  lib/iconv.in.h
+  lib/idx.h
+  lib/inet_ntop.c
+  lib/intprops.h
+  lib/inttypes.in.h
+  lib/ioctl.c
+  lib/isblank.c
+  lib/iswblank.c
+  lib/iswdigit.c
+  lib/iswxdigit.c
+  lib/itold.c
+  lib/langinfo.in.h
+  lib/lc-charset-dispatch.c
+  lib/lc-charset-dispatch.h
+  lib/libc-config.h
+  lib/libunistring.valgrind
+  lib/limits.in.h
+  lib/link.c
+  lib/listen.c
+  lib/localcharset.c
+  lib/localcharset.h
+  lib/locale.in.h
+  lib/localeconv.c
+  lib/lseek.c
+  lib/lstat.c
+  lib/malloc.c
+  lib/malloc/scratch_buffer.h
+  lib/malloc/scratch_buffer_dupfree.c
+  lib/malloc/scratch_buffer_grow.c
+  lib/malloc/scratch_buffer_grow_preserve.c
+  lib/malloc/scratch_buffer_set_array_size.c
+  lib/malloca.c
+  lib/malloca.h
+  lib/mbchar.c
+  lib/mbchar.h
+  lib/mbiter.c
+  lib/mbiter.h
+  lib/mbrtowc-impl-utf8.h
+  lib/mbrtowc-impl.h
+  lib/mbrtowc.c
+  lib/mbsinit.c
+  lib/mbsrtowcs-impl.h
+  lib/mbsrtowcs-state.c
+  lib/mbsrtowcs.c
+  lib/mbtowc-impl.h
+  lib/mbtowc-lock.c
+  lib/mbtowc-lock.h
+  lib/mbtowc.c
+  lib/md2.c
+  lib/md2.h
+  lib/md4.c
+  lib/md4.h
+  lib/md5.c
+  lib/md5.h
+  lib/memchr.c
+  lib/memchr.valgrind
+  lib/mempcpy.c
+  lib/memrchr.c
+  lib/minmax.h
+  lib/mkdir.c
+  lib/mkostemp.c
+  lib/mkstemp.c
+  lib/mktime-internal.h
+  lib/mktime.c
+  lib/msvc-inval.c
+  lib/msvc-inval.h
+  lib/msvc-nothrow.c
+  lib/msvc-nothrow.h
+  lib/nanosleep.c
+  lib/netdb.in.h
+  lib/netinet_in.in.h
+  lib/nl_langinfo-lock.c
+  lib/nl_langinfo.c
+  lib/open.c
+  lib/openat-die.c
+  lib/openat-priv.h
+  lib/openat-proc.c
+  lib/openat.c
+  lib/openat.h
+  lib/opendir.c
+  lib/os2-spawn.c
+  lib/os2-spawn.h
+  lib/pathmax.h
+  lib/pipe-safer.c
+  lib/pipe.c
+  lib/pipe2-safer.c
+  lib/pipe2.c
+  lib/printf-args.c
+  lib/printf-args.h
+  lib/printf-parse.c
+  lib/printf-parse.h
+  lib/quote.h
+  lib/quotearg.c
+  lib/quotearg.h
+  lib/raise.c
+  lib/rawmemchr.c
+  lib/rawmemchr.valgrind
+  lib/readdir.c
+  lib/readlink.c
+  lib/realloc.c
+  lib/recv.c
+  lib/regcomp.c
+  lib/regex.c
+  lib/regex.h
+  lib/regex_internal.c
+  lib/regex_internal.h
+  lib/regexec.c
+  lib/rewinddir.c
+  lib/same-inode.h
+  lib/save-cwd.c
+  lib/save-cwd.h
+  lib/sched.in.h
+  lib/scratch_buffer.h
+  lib/secure_getenv.c
+  lib/select.c
+  lib/send.c
+  lib/setlocale-lock.c
+  lib/setlocale_null.c
+  lib/setlocale_null.h
+  lib/setsockopt.c
+  lib/sha1.c
+  lib/sha1.h
+  lib/sha256.c
+  lib/sha256.h
+  lib/sha512.c
+  lib/sha512.h
+  lib/sig-handler.c
+  lib/sig-handler.h
+  lib/sigaction.c
+  lib/signal.in.h
+  lib/sigprocmask.c
+  lib/size_max.h
+  lib/snprintf.c
+  lib/socket.c
+  lib/sockets.c
+  lib/sockets.h
+  lib/spawn-pipe.c
+  lib/spawn-pipe.h
+  lib/spawn.c
+  lib/spawn.in.h
+  lib/spawn_faction_addchdir.c
+  lib/spawn_faction_addclose.c
+  lib/spawn_faction_adddup2.c
+  lib/spawn_faction_addopen.c
+  lib/spawn_faction_destroy.c
+  lib/spawn_faction_init.c
+  lib/spawn_int.h
+  lib/spawnattr_destroy.c
+  lib/spawnattr_init.c
+  lib/spawnattr_setflags.c
+  lib/spawnattr_setpgroup.c
+  lib/spawnattr_setsigmask.c
+  lib/spawni.c
+  lib/spawnp.c
+  lib/stat-time.c
+  lib/stat-time.h
+  lib/stat-w32.c
+  lib/stat-w32.h
+  lib/stat.c
+  lib/stdalign.in.h
+  lib/stdbool.in.h
+  lib/stddef.in.h
+  lib/stdint.in.h
+  lib/stdio-impl.h
+  lib/stdio-write.c
+  lib/stdio.in.h
+  lib/stdlib.in.h
+  lib/stpcpy.c
+  lib/str-two-way.h
+  lib/strcasecmp.c
+  lib/strchrnul.c
+  lib/strchrnul.valgrind
+  lib/strdup.c
+  lib/streq.h
+  lib/strerror-override.c
+  lib/strerror-override.h
+  lib/strerror.c
+  lib/strerror_r.c
+  lib/string.in.h
+  lib/strings.in.h
+  lib/stripslash.c
+  lib/strncasecmp.c
+  lib/strndup.c
+  lib/strnlen.c
+  lib/strnlen1.c
+  lib/strnlen1.h
+  lib/strpbrk.c
+  lib/strptime.c
+  lib/strtok_r.c
+  lib/strtol.c
+  lib/strtoll.c
+  lib/symlink.c
+  lib/sys-limits.h
+  lib/sys_file.in.h
+  lib/sys_ioctl.in.h
+  lib/sys_random.in.h
+  lib/sys_select.in.h
+  lib/sys_socket.c
+  lib/sys_socket.in.h
+  lib/sys_stat.in.h
+  lib/sys_time.in.h
+  lib/sys_types.in.h
+  lib/sys_uio.in.h
+  lib/sys_wait.in.h
+  lib/tempname.c
+  lib/tempname.h
+  lib/thread-optim.h
+  lib/time.in.h
+  lib/time_r.c
+  lib/timegm.c
+  lib/timespec.c
+  lib/timespec.h
+  lib/tmpdir.c
+  lib/tmpdir.h
+  lib/u64.c
+  lib/u64.h
+  lib/unicase.in.h
+  lib/unicase/cased.c
+  lib/unicase/cased.h
+  lib/unicase/caseprop.h
+  lib/unicase/context.h
+  lib/unicase/empty-prefix-context.c
+  lib/unicase/empty-suffix-context.c
+  lib/unicase/ignorable.c
+  lib/unicase/ignorable.h
+  lib/unicase/simple-mapping.h
+  lib/unicase/special-casing-table.gperf
+  lib/unicase/special-casing.c
+  lib/unicase/special-casing.in.h
+  lib/unicase/tolower.c
+  lib/unicase/tolower.h
+  lib/unicase/u-casemap.h
+  lib/unicase/u8-casemap.c
+  lib/unicase/u8-tolower.c
+  lib/unicase/unicasemap.h
+  lib/unictype.in.h
+  lib/unictype/bitmap.h
+  lib/unictype/combiningclass.c
+  lib/unictype/combiningclass.h
+  lib/unictype/pr_soft_dotted.c
+  lib/unictype/pr_soft_dotted.h
+  lib/uninorm.in.h
+  lib/uninorm/decompose-internal.c
+  lib/uninorm/decompose-internal.h
+  lib/uninorm/normalize-internal.h
+  lib/uninorm/u-normalize-internal.h
+  lib/uninorm/u8-normalize.c
+  lib/unistd--.h
+  lib/unistd-safer.h
+  lib/unistd.c
+  lib/unistd.in.h
+  lib/unistr.in.h
+  lib/unistr/u-cpy.h
+  lib/unistr/u8-cpy.c
+  lib/unistr/u8-mbtouc-unsafe-aux.c
+  lib/unistr/u8-mbtouc-unsafe.c
+  lib/unistr/u8-strlen.c
+  lib/unistr/u8-uctomb-aux.c
+  lib/unistr/u8-uctomb.c
+  lib/unitypes.in.h
+  lib/uniwidth.in.h
+  lib/uniwidth/cjk.h
+  lib/uniwidth/width.c
+  lib/unlink.c
+  lib/unlocked-io.h
+  lib/unused-parameter.h
+  lib/utime.c
+  lib/utime.in.h
+  lib/utimens.c
+  lib/utimens.h
+  lib/vasnprintf.c
+  lib/vasnprintf.h
+  lib/vasprintf.c
+  lib/verify.h
+  lib/vsnprintf.c
+  lib/w32sock.h
+  lib/wait-process.c
+  lib/wait-process.h
+  lib/waitpid.c
+  lib/warn-on-use.h
+  lib/wchar.in.h
+  lib/wcrtomb.c
+  lib/wctype-h.c
+  lib/wctype.in.h
+  lib/wcwidth.c
+  lib/windows-initguard.h
+  lib/windows-mutex.c
+  lib/windows-mutex.h
+  lib/windows-once.c
+  lib/windows-once.h
+  lib/windows-recmutex.c
+  lib/windows-recmutex.h
+  lib/windows-rwlock.c
+  lib/windows-rwlock.h
+  lib/windows-spawn.c
+  lib/windows-spawn.h
+  lib/wmemchr-impl.h
+  lib/wmemchr.c
+  lib/wmempcpy.c
+  lib/write.c
+  lib/xalloc-die.c
+  lib/xalloc-oversized.h
+  lib/xalloc.h
+  lib/xmalloc.c
+  lib/xmemdup0.c
+  lib/xmemdup0.h
+  lib/xsize.c
+  lib/xsize.h
+  lib/xstrndup.c
+  lib/xstrndup.h
+  m4/00gnulib.m4
+  m4/__inline.m4
+  m4/absolute-header.m4
+  m4/access.m4
+  m4/af_alg.m4
+  m4/alloca.m4
+  m4/arpa_inet_h.m4
+  m4/asm-underscore.m4
+  m4/base32.m4
+  m4/btowc.m4
+  m4/builtin-expect.m4
+  m4/byteswap.m4
+  m4/canonicalize.m4
+  m4/chdir-long.m4
+  m4/clock_time.m4
+  m4/close.m4
+  m4/closedir.m4
+  m4/codeset.m4
+  m4/ctype.m4
+  m4/d-ino.m4
+  m4/dirent_h.m4
+  m4/dirfd.m4
+  m4/double-slash-root.m4
+  m4/dup.m4
+  m4/dup2.m4
+  m4/eaccess.m4
+  m4/eealloc.m4
+  m4/environ.m4
+  m4/errno_h.m4
+  m4/error.m4
+  m4/exponentd.m4
+  m4/extensions.m4
+  m4/extern-inline.m4
+  m4/fatal-signal.m4
+  m4/fchdir.m4
+  m4/fcntl-o.m4
+  m4/fcntl.m4
+  m4/fcntl_h.m4
+  m4/fdopendir.m4
+  m4/fflush.m4
+  m4/filenamecat.m4
+  m4/findprog-in.m4
+  m4/flexmember.m4
+  m4/float_h.m4
+  m4/flock.m4
+  m4/fnmatch.m4
+  m4/fnmatch_h.m4
+  m4/fopen.m4
+  m4/fpurge.m4
+  m4/freading.m4
+  m4/free.m4
+  m4/fseek.m4
+  m4/fseeko.m4
+  m4/fstat.m4
+  m4/fstatat.m4
+  m4/ftell.m4
+  m4/ftello.m4
+  m4/futimens.m4
+  m4/getaddrinfo.m4
+  m4/getcwd-abort-bug.m4
+  m4/getcwd-path-max.m4
+  m4/getcwd.m4
+  m4/getdelim.m4
+  m4/getdtablesize.m4
+  m4/getgroups.m4
+  m4/getline.m4
+  m4/getopt.m4
+  m4/getpagesize.m4
+  m4/getpass.m4
+  m4/getprogname.m4
+  m4/getrandom.m4
+  m4/gettime.m4
+  m4/gettimeofday.m4
+  m4/gl-openssl.m4
+  m4/gnulib-common.m4
+  m4/group-member.m4
+  m4/host-cpu-c-abi.m4
+  m4/hostent.m4
+  m4/iconv.m4
+  m4/iconv_h.m4
+  m4/include_next.m4
+  m4/inet_ntop.m4
+  m4/inline.m4
+  m4/intmax_t.m4
+  m4/inttypes.m4
+  m4/inttypes_h.m4
+  m4/ioctl.m4
+  m4/isblank.m4
+  m4/iswblank.m4
+  m4/iswdigit.m4
+  m4/iswxdigit.m4
+  m4/langinfo_h.m4
+  m4/largefile.m4
+  m4/lib-ld.m4
+  m4/lib-link.m4
+  m4/lib-prefix.m4
+  m4/libunistring-base.m4
+  m4/libunistring-optional.m4
+  m4/libunistring.m4
+  m4/limits-h.m4
+  m4/link.m4
+  m4/localcharset.m4
+  m4/locale-fr.m4
+  m4/locale-ja.m4
+  m4/locale-zh.m4
+  m4/locale_h.m4
+  m4/localeconv.m4
+  m4/lock.m4
+  m4/lseek.m4
+  m4/lstat.m4
+  m4/malloc.m4
+  m4/malloca.m4
+  m4/math_h.m4
+  m4/mbchar.m4
+  m4/mbiter.m4
+  m4/mbrtowc.m4
+  m4/mbsinit.m4
+  m4/mbsrtowcs.m4
+  m4/mbstate_t.m4
+  m4/mbtowc.m4
+  m4/md4.m4
+  m4/md5.m4
+  m4/memchr.m4
+  m4/mempcpy.m4
+  m4/memrchr.m4
+  m4/minmax.m4
+  m4/mkdir.m4
+  m4/mkostemp.m4
+  m4/mkstemp.m4
+  m4/mktime.m4
+  m4/mmap-anon.m4
+  m4/mode_t.m4
+  m4/msvc-inval.m4
+  m4/msvc-nothrow.m4
+  m4/multiarch.m4
+  m4/nanosleep.m4
+  m4/netdb_h.m4
+  m4/netinet_in_h.m4
+  m4/nl_langinfo.m4
+  m4/nocrash.m4
+  m4/off_t.m4
+  m4/open-cloexec.m4
+  m4/open-slash.m4
+  m4/open.m4
+  m4/openat.m4
+  m4/opendir.m4
+  m4/pathmax.m4
+  m4/pid_t.m4
+  m4/pipe.m4
+  m4/pipe2.m4
+  m4/posix_spawn.m4
+  m4/posix_spawn_faction_addchdir.m4
+  m4/printf.m4
+  m4/pthread_rwlock_rdlock.m4
+  m4/quote.m4
+  m4/quotearg.m4
+  m4/raise.m4
+  m4/rawmemchr.m4
+  m4/readdir.m4
+  m4/readlink.m4
+  m4/realloc.m4
+  m4/regex.m4
+  m4/rewinddir.m4
+  m4/save-cwd.m4
+  m4/sched_h.m4
+  m4/secure_getenv.m4
+  m4/select.m4
+  m4/servent.m4
+  m4/setlocale_null.m4
+  m4/sh-filename.m4
+  m4/sha1.m4
+  m4/sha256.m4
+  m4/sha512.m4
+  m4/sig_atomic_t.m4
+  m4/sigaction.m4
+  m4/signal_h.m4
+  m4/signalblocking.m4
+  m4/sigpipe.m4
+  m4/size_max.m4
+  m4/snprintf.m4
+  m4/socketlib.m4
+  m4/sockets.m4
+  m4/socklen.m4
+  m4/sockpfaf.m4
+  m4/spawn-pipe.m4
+  m4/spawn_h.m4
+  m4/ssize_t.m4
+  m4/stat-time.m4
+  m4/stat.m4
+  m4/std-gnu11.m4
+  m4/stdalign.m4
+  m4/stdbool.m4
+  m4/stddef_h.m4
+  m4/stdint.m4
+  m4/stdint_h.m4
+  m4/stdio_h.m4
+  m4/stdlib_h.m4
+  m4/stpcpy.m4
+  m4/strcase.m4
+  m4/strchrnul.m4
+  m4/strdup.m4
+  m4/strerror.m4
+  m4/strerror_r.m4
+  m4/string_h.m4
+  m4/strings_h.m4
+  m4/strndup.m4
+  m4/strnlen.m4
+  m4/strpbrk.m4
+  m4/strptime.m4
+  m4/strtok_r.m4
+  m4/strtol.m4
+  m4/strtoll.m4
+  m4/symlink.m4
+  m4/sys_file_h.m4
+  m4/sys_ioctl_h.m4
+  m4/sys_random_h.m4
+  m4/sys_select_h.m4
+  m4/sys_socket_h.m4
+  m4/sys_stat_h.m4
+  m4/sys_time_h.m4
+  m4/sys_types_h.m4
+  m4/sys_uio_h.m4
+  m4/sys_wait_h.m4
+  m4/tempname.m4
+  m4/threadlib.m4
+  m4/time_h.m4
+  m4/time_r.m4
+  m4/timegm.m4
+  m4/timespec.m4
+  m4/tm_gmtoff.m4
+  m4/tmpdir.m4
+  m4/unistd-safer.m4
+  m4/unistd_h.m4
+  m4/unlink.m4
+  m4/unlocked-io.m4
+  m4/utime.m4
+  m4/utime_h.m4
+  m4/utimens.m4
+  m4/utimes.m4
+  m4/vasnprintf.m4
+  m4/vasprintf.m4
+  m4/visibility.m4
+  m4/vsnprintf.m4
+  m4/wait-process.m4
+  m4/waitpid.m4
+  m4/warn-on-use.m4
+  m4/warnings.m4
+  m4/wchar_h.m4
+  m4/wchar_t.m4
+  m4/wcrtomb.m4
+  m4/wctype_h.m4
+  m4/wcwidth.m4
+  m4/wint_t.m4
+  m4/wmemchr.m4
+  m4/wmempcpy.m4
+  m4/write.m4
+  m4/xalloc.m4
+  m4/xsize.m4
+  m4/xstrndup.m4
+  m4/zzgnulib.m4
+  top/GNUmakefile
+  top/maint.mk
+])
diff --git a/m4/group-member.m4 b/m4/group-member.m4
new file mode 100644
index 0000000..ad7368c
--- /dev/null
+++ b/m4/group-member.m4
@@ -0,0 +1,29 @@
+# serial 14
+
+# Copyright (C) 1999-2001, 2003-2007, 2009-2020 Free Software Foundation, Inc.
+
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+dnl Written by Jim Meyering
+
+AC_DEFUN([gl_FUNC_GROUP_MEMBER],
+[
+  AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
+
+  dnl Persuade glibc <unistd.h> to declare group_member().
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
+
+  dnl Do this replacement check manually because I want the hyphen
+  dnl (not the underscore) in the filename.
+  AC_CHECK_FUNC([group_member], , [
+    HAVE_GROUP_MEMBER=0
+  ])
+])
+
+# Prerequisites of lib/group-member.c.
+AC_DEFUN([gl_PREREQ_GROUP_MEMBER],
+[
+  AC_REQUIRE([AC_FUNC_GETGROUPS])
+])
diff --git a/m4/host-cpu-c-abi.m4 b/m4/host-cpu-c-abi.m4
new file mode 100644
index 0000000..6db2aa2
--- /dev/null
+++ b/m4/host-cpu-c-abi.m4
@@ -0,0 +1,675 @@
+# host-cpu-c-abi.m4 serial 13
+dnl Copyright (C) 2002-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl From Bruno Haible and Sam Steingold.
+
+dnl Sets the HOST_CPU variable to the canonical name of the CPU.
+dnl Sets the HOST_CPU_C_ABI variable to the canonical name of the CPU with its
+dnl C language ABI (application binary interface).
+dnl Also defines __${HOST_CPU}__ and __${HOST_CPU_C_ABI}__ as C macros in
+dnl config.h.
+dnl
+dnl This canonical name can be used to select a particular assembly language
+dnl source file that will interoperate with C code on the given host.
+dnl
+dnl For example:
+dnl * 'i386' and 'sparc' are different canonical names, because code for i386
+dnl   will not run on SPARC CPUs and vice versa. They have different
+dnl   instruction sets.
+dnl * 'sparc' and 'sparc64' are different canonical names, because code for
+dnl   'sparc' and code for 'sparc64' cannot be linked together: 'sparc' code
+dnl   contains 32-bit instructions, whereas 'sparc64' code contains 64-bit
+dnl   instructions. A process on a SPARC CPU can be in 32-bit mode or in 64-bit
+dnl   mode, but not both.
+dnl * 'mips' and 'mipsn32' are different canonical names, because they use
+dnl   different argument passing and return conventions for C functions, and
+dnl   although the instruction set of 'mips' is a large subset of the
+dnl   instruction set of 'mipsn32'.
+dnl * 'mipsn32' and 'mips64' are different canonical names, because they use
+dnl   different sizes for the C types like 'int' and 'void *', and although
+dnl   the instruction sets of 'mipsn32' and 'mips64' are the same.
+dnl * The same canonical name is used for different endiannesses. You can
+dnl   determine the endianness through preprocessor symbols:
+dnl   - 'arm': test __ARMEL__.
+dnl   - 'mips', 'mipsn32', 'mips64': test _MIPSEB vs. _MIPSEL.
+dnl   - 'powerpc64': test _BIG_ENDIAN vs. _LITTLE_ENDIAN.
+dnl * The same name 'i386' is used for CPUs of type i386, i486, i586
+dnl   (Pentium), AMD K7, Pentium II, Pentium IV, etc., because
+dnl   - Instructions that do not exist on all of these CPUs (cmpxchg,
+dnl     MMX, SSE, SSE2, 3DNow! etc.) are not frequently used. If your
+dnl     assembly language source files use such instructions, you will
+dnl     need to make the distinction.
+dnl   - Speed of execution of the common instruction set is reasonable across
+dnl     the entire family of CPUs. If you have assembly language source files
+dnl     that are optimized for particular CPU types (like GNU gmp has), you
+dnl     will need to make the distinction.
+dnl   See <https://en.wikipedia.org/wiki/X86_instruction_listings>.
+AC_DEFUN([gl_HOST_CPU_C_ABI],
+[
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  AC_REQUIRE([gl_C_ASM])
+  AC_CACHE_CHECK([host CPU and C ABI], [gl_cv_host_cpu_c_abi],
+    [case "$host_cpu" in
+
+changequote(,)dnl
+       i[34567]86 )
+changequote([,])dnl
+         gl_cv_host_cpu_c_abi=i386
+         ;;
+
+       x86_64 )
+         # On x86_64 systems, the C compiler may be generating code in one of
+         # these ABIs:
+         # - 64-bit instruction set, 64-bit pointers, 64-bit 'long': x86_64.
+         # - 64-bit instruction set, 64-bit pointers, 32-bit 'long': x86_64
+         #   with native Windows (mingw, MSVC).
+         # - 64-bit instruction set, 32-bit pointers, 32-bit 'long': x86_64-x32.
+         # - 32-bit instruction set, 32-bit pointers, 32-bit 'long': i386.
+         AC_COMPILE_IFELSE(
+           [AC_LANG_SOURCE(
+              [[#if (defined __x86_64__ || defined __amd64__ \
+                     || defined _M_X64 || defined _M_AMD64)
+                 int ok;
+                #else
+                 error fail
+                #endif
+              ]])],
+           [AC_COMPILE_IFELSE(
+              [AC_LANG_SOURCE(
+                 [[#if defined __ILP32__ || defined _ILP32
+                    int ok;
+                   #else
+                    error fail
+                   #endif
+                 ]])],
+              [gl_cv_host_cpu_c_abi=x86_64-x32],
+              [gl_cv_host_cpu_c_abi=x86_64])],
+           [gl_cv_host_cpu_c_abi=i386])
+         ;;
+
+changequote(,)dnl
+       alphaev[4-8] | alphaev56 | alphapca5[67] | alphaev6[78] )
+changequote([,])dnl
+         gl_cv_host_cpu_c_abi=alpha
+         ;;
+
+       arm* | aarch64 )
+         # Assume arm with EABI.
+         # On arm64 systems, the C compiler may be generating code in one of
+         # these ABIs:
+         # - aarch64 instruction set, 64-bit pointers, 64-bit 'long': arm64.
+         # - aarch64 instruction set, 32-bit pointers, 32-bit 'long': arm64-ilp32.
+         # - 32-bit instruction set, 32-bit pointers, 32-bit 'long': arm or armhf.
+         AC_COMPILE_IFELSE(
+           [AC_LANG_SOURCE(
+              [[#ifdef __aarch64__
+                 int ok;
+                #else
+                 error fail
+                #endif
+              ]])],
+           [AC_COMPILE_IFELSE(
+              [AC_LANG_SOURCE(
+                [[#if defined __ILP32__ || defined _ILP32
+                   int ok;
+                  #else
+                   error fail
+                  #endif
+                ]])],
+              [gl_cv_host_cpu_c_abi=arm64-ilp32],
+              [gl_cv_host_cpu_c_abi=arm64])],
+           [# Don't distinguish little-endian and big-endian arm, since they
+            # don't require different machine code for simple operations and
+            # since the user can distinguish them through the preprocessor
+            # defines __ARMEL__ vs. __ARMEB__.
+            # But distinguish arm which passes floating-point arguments and
+            # return values in integer registers (r0, r1, ...) - this is
+            # gcc -mfloat-abi=soft or gcc -mfloat-abi=softfp - from arm which
+            # passes them in float registers (s0, s1, ...) and double registers
+            # (d0, d1, ...) - this is gcc -mfloat-abi=hard. GCC 4.6 or newer
+            # sets the preprocessor defines __ARM_PCS (for the first case) and
+            # __ARM_PCS_VFP (for the second case), but older GCC does not.
+            echo 'double ddd; void func (double dd) { ddd = dd; }' > conftest.c
+            # Look for a reference to the register d0 in the .s file.
+            AC_TRY_COMMAND(${CC-cc} $CFLAGS $CPPFLAGS $gl_c_asm_opt conftest.c) >/dev/null 2>&1
+            if LC_ALL=C grep 'd0,' conftest.$gl_asmext >/dev/null; then
+              gl_cv_host_cpu_c_abi=armhf
+            else
+              gl_cv_host_cpu_c_abi=arm
+            fi
+            rm -f conftest*
+           ])
+         ;;
+
+       hppa1.0 | hppa1.1 | hppa2.0* | hppa64 )
+         # On hppa, the C compiler may be generating 32-bit code or 64-bit
+         # code. In the latter case, it defines _LP64 and __LP64__.
+         AC_COMPILE_IFELSE(
+           [AC_LANG_SOURCE(
+              [[#ifdef __LP64__
+                 int ok;
+                #else
+                 error fail
+                #endif
+              ]])],
+           [gl_cv_host_cpu_c_abi=hppa64],
+           [gl_cv_host_cpu_c_abi=hppa])
+         ;;
+
+       ia64* )
+         # On ia64 on HP-UX, the C compiler may be generating 64-bit code or
+         # 32-bit code. In the latter case, it defines _ILP32.
+         AC_COMPILE_IFELSE(
+           [AC_LANG_SOURCE(
+              [[#ifdef _ILP32
+                 int ok;
+                #else
+                 error fail
+                #endif
+              ]])],
+           [gl_cv_host_cpu_c_abi=ia64-ilp32],
+           [gl_cv_host_cpu_c_abi=ia64])
+         ;;
+
+       mips* )
+         # We should also check for (_MIPS_SZPTR == 64), but gcc keeps this
+         # at 32.
+         AC_COMPILE_IFELSE(
+           [AC_LANG_SOURCE(
+              [[#if defined _MIPS_SZLONG && (_MIPS_SZLONG == 64)
+                 int ok;
+                #else
+                 error fail
+                #endif
+              ]])],
+           [gl_cv_host_cpu_c_abi=mips64],
+           [# In the n32 ABI, _ABIN32 is defined, _ABIO32 is not defined (but
+            # may later get defined by <sgidefs.h>), and _MIPS_SIM == _ABIN32.
+            # In the 32 ABI, _ABIO32 is defined, _ABIN32 is not defined (but
+            # may later get defined by <sgidefs.h>), and _MIPS_SIM == _ABIO32.
+            AC_COMPILE_IFELSE(
+              [AC_LANG_SOURCE(
+                 [[#if (_MIPS_SIM == _ABIN32)
+                    int ok;
+                   #else
+                    error fail
+                   #endif
+                 ]])],
+              [gl_cv_host_cpu_c_abi=mipsn32],
+              [gl_cv_host_cpu_c_abi=mips])])
+         ;;
+
+       powerpc* )
+         # Different ABIs are in use on AIX vs. Mac OS X vs. Linux,*BSD.
+         # No need to distinguish them here; the caller may distinguish
+         # them based on the OS.
+         # On powerpc64 systems, the C compiler may still be generating
+         # 32-bit code. And on powerpc-ibm-aix systems, the C compiler may
+         # be generating 64-bit code.
+         AC_COMPILE_IFELSE(
+           [AC_LANG_SOURCE(
+              [[#if defined __powerpc64__ || defined _ARCH_PPC64
+                 int ok;
+                #else
+                 error fail
+                #endif
+              ]])],
+           [# On powerpc64, there are two ABIs on Linux: The AIX compatible
+            # one and the ELFv2 one. The latter defines _CALL_ELF=2.
+            AC_COMPILE_IFELSE(
+              [AC_LANG_SOURCE(
+                 [[#if defined _CALL_ELF && _CALL_ELF == 2
+                    int ok;
+                   #else
+                    error fail
+                   #endif
+                 ]])],
+              [gl_cv_host_cpu_c_abi=powerpc64-elfv2],
+              [gl_cv_host_cpu_c_abi=powerpc64])
+           ],
+           [gl_cv_host_cpu_c_abi=powerpc])
+         ;;
+
+       rs6000 )
+         gl_cv_host_cpu_c_abi=powerpc
+         ;;
+
+       riscv32 | riscv64 )
+         # There are 2 architectures (with variants): rv32* and rv64*.
+         AC_COMPILE_IFELSE(
+           [AC_LANG_SOURCE(
+              [[#if __riscv_xlen == 64
+                  int ok;
+                #else
+                  error fail
+                #endif
+              ]])],
+           [cpu=riscv64],
+           [cpu=riscv32])
+         # There are 6 ABIs: ilp32, ilp32f, ilp32d, lp64, lp64f, lp64d.
+         # Size of 'long' and 'void *':
+         AC_COMPILE_IFELSE(
+           [AC_LANG_SOURCE(
+              [[#if defined __LP64__
+                  int ok;
+                #else
+                  error fail
+                #endif
+              ]])],
+           [main_abi=lp64],
+           [main_abi=ilp32])
+         # Float ABIs:
+         # __riscv_float_abi_double:
+         #   'float' and 'double' are passed in floating-point registers.
+         # __riscv_float_abi_single:
+         #   'float' are passed in floating-point registers.
+         # __riscv_float_abi_soft:
+         #   No values are passed in floating-point registers.
+         AC_COMPILE_IFELSE(
+           [AC_LANG_SOURCE(
+              [[#if defined __riscv_float_abi_double
+                  int ok;
+                #else
+                  error fail
+                #endif
+              ]])],
+           [float_abi=d],
+           [AC_COMPILE_IFELSE(
+              [AC_LANG_SOURCE(
+                 [[#if defined __riscv_float_abi_single
+                     int ok;
+                   #else
+                     error fail
+                   #endif
+                 ]])],
+              [float_abi=f],
+              [float_abi=''])
+           ])
+         gl_cv_host_cpu_c_abi="${cpu}-${main_abi}${float_abi}"
+         ;;
+
+       s390* )
+         # On s390x, the C compiler may be generating 64-bit (= s390x) code
+         # or 31-bit (= s390) code.
+         AC_COMPILE_IFELSE(
+           [AC_LANG_SOURCE(
+              [[#if defined __LP64__ || defined __s390x__
+                  int ok;
+                #else
+                  error fail
+                #endif
+              ]])],
+           [gl_cv_host_cpu_c_abi=s390x],
+           [gl_cv_host_cpu_c_abi=s390])
+         ;;
+
+       sparc | sparc64 )
+         # UltraSPARCs running Linux have `uname -m` = "sparc64", but the
+         # C compiler still generates 32-bit code.
+         AC_COMPILE_IFELSE(
+           [AC_LANG_SOURCE(
+              [[#if defined __sparcv9 || defined __arch64__
+                 int ok;
+                #else
+                 error fail
+                #endif
+              ]])],
+           [gl_cv_host_cpu_c_abi=sparc64],
+           [gl_cv_host_cpu_c_abi=sparc])
+         ;;
+
+       *)
+         gl_cv_host_cpu_c_abi="$host_cpu"
+         ;;
+     esac
+    ])
+
+  dnl In most cases, $HOST_CPU and $HOST_CPU_C_ABI are the same.
+  HOST_CPU=`echo "$gl_cv_host_cpu_c_abi" | sed -e 's/-.*//'`
+  HOST_CPU_C_ABI="$gl_cv_host_cpu_c_abi"
+  AC_SUBST([HOST_CPU])
+  AC_SUBST([HOST_CPU_C_ABI])
+
+  # This was
+  #   AC_DEFINE_UNQUOTED([__${HOST_CPU}__])
+  #   AC_DEFINE_UNQUOTED([__${HOST_CPU_C_ABI}__])
+  # earlier, but KAI C++ 3.2d doesn't like this.
+  sed -e 's/-/_/g' >> confdefs.h <<EOF
+#ifndef __${HOST_CPU}__
+#define __${HOST_CPU}__ 1
+#endif
+#ifndef __${HOST_CPU_C_ABI}__
+#define __${HOST_CPU_C_ABI}__ 1
+#endif
+EOF
+  AH_TOP([/* CPU and C ABI indicator */
+#ifndef __i386__
+#undef __i386__
+#endif
+#ifndef __x86_64_x32__
+#undef __x86_64_x32__
+#endif
+#ifndef __x86_64__
+#undef __x86_64__
+#endif
+#ifndef __alpha__
+#undef __alpha__
+#endif
+#ifndef __arm__
+#undef __arm__
+#endif
+#ifndef __armhf__
+#undef __armhf__
+#endif
+#ifndef __arm64_ilp32__
+#undef __arm64_ilp32__
+#endif
+#ifndef __arm64__
+#undef __arm64__
+#endif
+#ifndef __hppa__
+#undef __hppa__
+#endif
+#ifndef __hppa64__
+#undef __hppa64__
+#endif
+#ifndef __ia64_ilp32__
+#undef __ia64_ilp32__
+#endif
+#ifndef __ia64__
+#undef __ia64__
+#endif
+#ifndef __m68k__
+#undef __m68k__
+#endif
+#ifndef __mips__
+#undef __mips__
+#endif
+#ifndef __mipsn32__
+#undef __mipsn32__
+#endif
+#ifndef __mips64__
+#undef __mips64__
+#endif
+#ifndef __powerpc__
+#undef __powerpc__
+#endif
+#ifndef __powerpc64__
+#undef __powerpc64__
+#endif
+#ifndef __powerpc64_elfv2__
+#undef __powerpc64_elfv2__
+#endif
+#ifndef __riscv32__
+#undef __riscv32__
+#endif
+#ifndef __riscv64__
+#undef __riscv64__
+#endif
+#ifndef __riscv32_ilp32__
+#undef __riscv32_ilp32__
+#endif
+#ifndef __riscv32_ilp32f__
+#undef __riscv32_ilp32f__
+#endif
+#ifndef __riscv32_ilp32d__
+#undef __riscv32_ilp32d__
+#endif
+#ifndef __riscv64_ilp32__
+#undef __riscv64_ilp32__
+#endif
+#ifndef __riscv64_ilp32f__
+#undef __riscv64_ilp32f__
+#endif
+#ifndef __riscv64_ilp32d__
+#undef __riscv64_ilp32d__
+#endif
+#ifndef __riscv64_lp64__
+#undef __riscv64_lp64__
+#endif
+#ifndef __riscv64_lp64f__
+#undef __riscv64_lp64f__
+#endif
+#ifndef __riscv64_lp64d__
+#undef __riscv64_lp64d__
+#endif
+#ifndef __s390__
+#undef __s390__
+#endif
+#ifndef __s390x__
+#undef __s390x__
+#endif
+#ifndef __sh__
+#undef __sh__
+#endif
+#ifndef __sparc__
+#undef __sparc__
+#endif
+#ifndef __sparc64__
+#undef __sparc64__
+#endif
+])
+
+])
+
+
+dnl Sets the HOST_CPU_C_ABI_32BIT variable to 'yes' if the C language ABI
+dnl (application binary interface) is a 32-bit one, to 'no' if it is a 64-bit
+dnl one, or to 'unknown' if unknown.
+dnl This is a simplified variant of gl_HOST_CPU_C_ABI.
+AC_DEFUN([gl_HOST_CPU_C_ABI_32BIT],
+[
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  AC_CACHE_CHECK([32-bit host C ABI], [gl_cv_host_cpu_c_abi_32bit],
+    [if test -n "$gl_cv_host_cpu_c_abi"; then
+       case "$gl_cv_host_cpu_c_abi" in
+         i386 | x86_64-x32 | arm | armhf | arm64-ilp32 | hppa | ia64-ilp32 | mips | mipsn32 | powerpc | riscv*-ilp32* | s390 | sparc)
+           gl_cv_host_cpu_c_abi_32bit=yes ;;
+         x86_64 | alpha | arm64 | hppa64 | ia64 | mips64 | powerpc64 | powerpc64-elfv2 | riscv*-lp64* | s390x | sparc64 )
+           gl_cv_host_cpu_c_abi_32bit=no ;;
+         *)
+           gl_cv_host_cpu_c_abi_32bit=unknown ;;
+       esac
+     else
+       case "$host_cpu" in
+
+         # CPUs that only support a 32-bit ABI.
+         arc \
+         | bfin \
+         | cris* \
+         | csky \
+         | epiphany \
+         | ft32 \
+         | h8300 \
+         | m68k \
+         | microblaze | microblazeel \
+         | nds32 | nds32le | nds32be \
+         | nios2 | nios2eb | nios2el \
+         | or1k* \
+         | or32 \
+         | sh | sh[1234] | sh[1234]e[lb] \
+         | tic6x \
+         | xtensa* )
+           gl_cv_host_cpu_c_abi_32bit=yes
+           ;;
+
+         # CPUs that only support a 64-bit ABI.
+changequote(,)dnl
+         alpha | alphaev[4-8] | alphaev56 | alphapca5[67] | alphaev6[78] \
+         | mmix )
+changequote([,])dnl
+           gl_cv_host_cpu_c_abi_32bit=no
+           ;;
+
+changequote(,)dnl
+         i[34567]86 )
+changequote([,])dnl
+           gl_cv_host_cpu_c_abi_32bit=yes
+           ;;
+
+         x86_64 )
+           # On x86_64 systems, the C compiler may be generating code in one of
+           # these ABIs:
+           # - 64-bit instruction set, 64-bit pointers, 64-bit 'long': x86_64.
+           # - 64-bit instruction set, 64-bit pointers, 32-bit 'long': x86_64
+           #   with native Windows (mingw, MSVC).
+           # - 64-bit instruction set, 32-bit pointers, 32-bit 'long': x86_64-x32.
+           # - 32-bit instruction set, 32-bit pointers, 32-bit 'long': i386.
+           AC_COMPILE_IFELSE(
+             [AC_LANG_SOURCE(
+                [[#if (defined __x86_64__ || defined __amd64__ \
+                       || defined _M_X64 || defined _M_AMD64) \
+                      && !(defined __ILP32__ || defined _ILP32)
+                   int ok;
+                  #else
+                   error fail
+                  #endif
+                ]])],
+             [gl_cv_host_cpu_c_abi_32bit=no],
+             [gl_cv_host_cpu_c_abi_32bit=yes])
+           ;;
+
+         arm* | aarch64 )
+           # Assume arm with EABI.
+           # On arm64 systems, the C compiler may be generating code in one of
+           # these ABIs:
+           # - aarch64 instruction set, 64-bit pointers, 64-bit 'long': arm64.
+           # - aarch64 instruction set, 32-bit pointers, 32-bit 'long': arm64-ilp32.
+           # - 32-bit instruction set, 32-bit pointers, 32-bit 'long': arm or armhf.
+           AC_COMPILE_IFELSE(
+             [AC_LANG_SOURCE(
+                [[#if defined __aarch64__ && !(defined __ILP32__ || defined _ILP32)
+                   int ok;
+                  #else
+                   error fail
+                  #endif
+                ]])],
+             [gl_cv_host_cpu_c_abi_32bit=no],
+             [gl_cv_host_cpu_c_abi_32bit=yes])
+           ;;
+
+         hppa1.0 | hppa1.1 | hppa2.0* | hppa64 )
+           # On hppa, the C compiler may be generating 32-bit code or 64-bit
+           # code. In the latter case, it defines _LP64 and __LP64__.
+           AC_COMPILE_IFELSE(
+             [AC_LANG_SOURCE(
+                [[#ifdef __LP64__
+                   int ok;
+                  #else
+                   error fail
+                  #endif
+                ]])],
+             [gl_cv_host_cpu_c_abi_32bit=no],
+             [gl_cv_host_cpu_c_abi_32bit=yes])
+           ;;
+
+         ia64* )
+           # On ia64 on HP-UX, the C compiler may be generating 64-bit code or
+           # 32-bit code. In the latter case, it defines _ILP32.
+           AC_COMPILE_IFELSE(
+             [AC_LANG_SOURCE(
+                [[#ifdef _ILP32
+                   int ok;
+                  #else
+                   error fail
+                  #endif
+                ]])],
+             [gl_cv_host_cpu_c_abi_32bit=yes],
+             [gl_cv_host_cpu_c_abi_32bit=no])
+           ;;
+
+         mips* )
+           # We should also check for (_MIPS_SZPTR == 64), but gcc keeps this
+           # at 32.
+           AC_COMPILE_IFELSE(
+             [AC_LANG_SOURCE(
+                [[#if defined _MIPS_SZLONG && (_MIPS_SZLONG == 64)
+                   int ok;
+                  #else
+                   error fail
+                  #endif
+                ]])],
+             [gl_cv_host_cpu_c_abi_32bit=no],
+             [gl_cv_host_cpu_c_abi_32bit=yes])
+           ;;
+
+         powerpc* )
+           # Different ABIs are in use on AIX vs. Mac OS X vs. Linux,*BSD.
+           # No need to distinguish them here; the caller may distinguish
+           # them based on the OS.
+           # On powerpc64 systems, the C compiler may still be generating
+           # 32-bit code. And on powerpc-ibm-aix systems, the C compiler may
+           # be generating 64-bit code.
+           AC_COMPILE_IFELSE(
+             [AC_LANG_SOURCE(
+                [[#if defined __powerpc64__ || defined _ARCH_PPC64
+                   int ok;
+                  #else
+                   error fail
+                  #endif
+                ]])],
+             [gl_cv_host_cpu_c_abi_32bit=no],
+             [gl_cv_host_cpu_c_abi_32bit=yes])
+           ;;
+
+         rs6000 )
+           gl_cv_host_cpu_c_abi_32bit=yes
+           ;;
+
+         riscv32 | riscv64 )
+           # There are 6 ABIs: ilp32, ilp32f, ilp32d, lp64, lp64f, lp64d.
+           # Size of 'long' and 'void *':
+           AC_COMPILE_IFELSE(
+             [AC_LANG_SOURCE(
+                [[#if defined __LP64__
+                    int ok;
+                  #else
+                    error fail
+                  #endif
+                ]])],
+             [gl_cv_host_cpu_c_abi_32bit=no],
+             [gl_cv_host_cpu_c_abi_32bit=yes])
+           ;;
+
+         s390* )
+           # On s390x, the C compiler may be generating 64-bit (= s390x) code
+           # or 31-bit (= s390) code.
+           AC_COMPILE_IFELSE(
+             [AC_LANG_SOURCE(
+                [[#if defined __LP64__ || defined __s390x__
+                    int ok;
+                  #else
+                    error fail
+                  #endif
+                ]])],
+             [gl_cv_host_cpu_c_abi_32bit=no],
+             [gl_cv_host_cpu_c_abi_32bit=yes])
+           ;;
+
+         sparc | sparc64 )
+           # UltraSPARCs running Linux have `uname -m` = "sparc64", but the
+           # C compiler still generates 32-bit code.
+           AC_COMPILE_IFELSE(
+             [AC_LANG_SOURCE(
+                [[#if defined __sparcv9 || defined __arch64__
+                   int ok;
+                  #else
+                   error fail
+                  #endif
+                ]])],
+             [gl_cv_host_cpu_c_abi_32bit=no],
+             [gl_cv_host_cpu_c_abi_32bit=yes])
+           ;;
+
+         *)
+           gl_cv_host_cpu_c_abi_32bit=unknown
+           ;;
+       esac
+     fi
+    ])
+
+  HOST_CPU_C_ABI_32BIT="$gl_cv_host_cpu_c_abi_32bit"
+])
diff --git a/m4/hostent.m4 b/m4/hostent.m4
new file mode 100644
index 0000000..2860452
--- /dev/null
+++ b/m4/hostent.m4
@@ -0,0 +1,49 @@
+# hostent.m4 serial 3
+dnl Copyright (C) 2008, 2010-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_HOSTENT],
+[
+  dnl Where are gethostent(), sethostent(), endhostent(), gethostbyname(),
+  dnl gethostbyaddr() defined?
+  dnl - On Solaris < 11.4, they are in libnsl. Ignore libxnet.
+  dnl - On Haiku, they are in libnetwork.
+  dnl - On BeOS, they are in libnet.
+  dnl - On native Windows, they are in ws2_32.dll.
+  dnl - Otherwise they are in libc.
+  AC_REQUIRE([gl_HEADER_SYS_SOCKET])dnl for HAVE_SYS_SOCKET_H, HAVE_WINSOCK2_H
+  HOSTENT_LIB=
+  gl_saved_libs="$LIBS"
+  AC_SEARCH_LIBS([gethostbyname], [nsl network net],
+    [if test "$ac_cv_search_gethostbyname" != "none required"; then
+       HOSTENT_LIB="$ac_cv_search_gethostbyname"
+     fi])
+  LIBS="$gl_saved_libs"
+  if test -z "$HOSTENT_LIB"; then
+    AC_CHECK_FUNCS([gethostbyname], , [
+      AC_CACHE_CHECK([for gethostbyname in winsock2.h and -lws2_32],
+        [gl_cv_w32_gethostbyname],
+        [gl_cv_w32_gethostbyname=no
+         gl_save_LIBS="$LIBS"
+         LIBS="$LIBS -lws2_32"
+         AC_LINK_IFELSE(
+           [AC_LANG_PROGRAM(
+              [[
+#ifdef HAVE_WINSOCK2_H
+#include <winsock2.h>
+#endif
+#include <stddef.h>
+              ]],
+              [[gethostbyname(NULL);]])],
+           [gl_cv_w32_gethostbyname=yes])
+         LIBS="$gl_save_LIBS"
+        ])
+      if test "$gl_cv_w32_gethostbyname" = "yes"; then
+        HOSTENT_LIB="-lws2_32"
+      fi
+    ])
+  fi
+  AC_SUBST([HOSTENT_LIB])
+])
diff --git a/m4/iconv.m4 b/m4/iconv.m4
new file mode 100644
index 0000000..f8a536b
--- /dev/null
+++ b/m4/iconv.m4
@@ -0,0 +1,282 @@
+# iconv.m4 serial 23
+dnl Copyright (C) 2000-2002, 2007-2014, 2016-2020 Free Software Foundation,
+dnl Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl From Bruno Haible.
+
+AC_PREREQ([2.64])
+
+dnl Note: AM_ICONV is documented in the GNU gettext manual
+dnl <https://www.gnu.org/software/gettext/manual/html_node/AM_005fICONV.html>.
+dnl Don't make changes that are incompatible with that documentation!
+
+AC_DEFUN([AM_ICONV_LINKFLAGS_BODY],
+[
+  dnl Prerequisites of AC_LIB_LINKFLAGS_BODY.
+  AC_REQUIRE([AC_LIB_PREPARE_PREFIX])
+  AC_REQUIRE([AC_LIB_RPATH])
+
+  dnl Search for libiconv and define LIBICONV, LTLIBICONV and INCICONV
+  dnl accordingly.
+  AC_LIB_LINKFLAGS_BODY([iconv])
+])
+
+AC_DEFUN([AM_ICONV_LINK],
+[
+  dnl Some systems have iconv in libc, some have it in libiconv (OSF/1 and
+  dnl those with the standalone portable GNU libiconv installed).
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+
+  dnl Search for libiconv and define LIBICONV, LTLIBICONV and INCICONV
+  dnl accordingly.
+  AC_REQUIRE([AM_ICONV_LINKFLAGS_BODY])
+
+  dnl Add $INCICONV to CPPFLAGS before performing the following checks,
+  dnl because if the user has installed libiconv and not disabled its use
+  dnl via --without-libiconv-prefix, he wants to use it. The first
+  dnl AC_LINK_IFELSE will then fail, the second AC_LINK_IFELSE will succeed.
+  am_save_CPPFLAGS="$CPPFLAGS"
+  AC_LIB_APPENDTOVAR([CPPFLAGS], [$INCICONV])
+
+  AC_CACHE_CHECK([for iconv], [am_cv_func_iconv], [
+    am_cv_func_iconv="no, consider installing GNU libiconv"
+    am_cv_lib_iconv=no
+    AC_LINK_IFELSE(
+      [AC_LANG_PROGRAM(
+         [[
+#include <stdlib.h>
+#include <iconv.h>
+         ]],
+         [[iconv_t cd = iconv_open("","");
+           iconv(cd,NULL,NULL,NULL,NULL);
+           iconv_close(cd);]])],
+      [am_cv_func_iconv=yes])
+    if test "$am_cv_func_iconv" != yes; then
+      am_save_LIBS="$LIBS"
+      LIBS="$LIBS $LIBICONV"
+      AC_LINK_IFELSE(
+        [AC_LANG_PROGRAM(
+           [[
+#include <stdlib.h>
+#include <iconv.h>
+           ]],
+           [[iconv_t cd = iconv_open("","");
+             iconv(cd,NULL,NULL,NULL,NULL);
+             iconv_close(cd);]])],
+        [am_cv_lib_iconv=yes]
+        [am_cv_func_iconv=yes])
+      LIBS="$am_save_LIBS"
+    fi
+  ])
+  if test "$am_cv_func_iconv" = yes; then
+    AC_CACHE_CHECK([for working iconv], [am_cv_func_iconv_works], [
+      dnl This tests against bugs in AIX 5.1, AIX 6.1..7.1, HP-UX 11.11,
+      dnl Solaris 10.
+      am_save_LIBS="$LIBS"
+      if test $am_cv_lib_iconv = yes; then
+        LIBS="$LIBS $LIBICONV"
+      fi
+      am_cv_func_iconv_works=no
+      for ac_iconv_const in '' 'const'; do
+        AC_RUN_IFELSE(
+          [AC_LANG_PROGRAM(
+             [[
+#include <iconv.h>
+#include <string.h>
+
+#ifndef ICONV_CONST
+# define ICONV_CONST $ac_iconv_const
+#endif
+             ]],
+             [[int result = 0;
+  /* Test against AIX 5.1 bug: Failures are not distinguishable from successful
+     returns.  */
+  {
+    iconv_t cd_utf8_to_88591 = iconv_open ("ISO8859-1", "UTF-8");
+    if (cd_utf8_to_88591 != (iconv_t)(-1))
+      {
+        static ICONV_CONST char input[] = "\342\202\254"; /* EURO SIGN */
+        char buf[10];
+        ICONV_CONST char *inptr = input;
+        size_t inbytesleft = strlen (input);
+        char *outptr = buf;
+        size_t outbytesleft = sizeof (buf);
+        size_t res = iconv (cd_utf8_to_88591,
+                            &inptr, &inbytesleft,
+                            &outptr, &outbytesleft);
+        if (res == 0)
+          result |= 1;
+        iconv_close (cd_utf8_to_88591);
+      }
+  }
+  /* Test against Solaris 10 bug: Failures are not distinguishable from
+     successful returns.  */
+  {
+    iconv_t cd_ascii_to_88591 = iconv_open ("ISO8859-1", "646");
+    if (cd_ascii_to_88591 != (iconv_t)(-1))
+      {
+        static ICONV_CONST char input[] = "\263";
+        char buf[10];
+        ICONV_CONST char *inptr = input;
+        size_t inbytesleft = strlen (input);
+        char *outptr = buf;
+        size_t outbytesleft = sizeof (buf);
+        size_t res = iconv (cd_ascii_to_88591,
+                            &inptr, &inbytesleft,
+                            &outptr, &outbytesleft);
+        if (res == 0)
+          result |= 2;
+        iconv_close (cd_ascii_to_88591);
+      }
+  }
+  /* Test against AIX 6.1..7.1 bug: Buffer overrun.  */
+  {
+    iconv_t cd_88591_to_utf8 = iconv_open ("UTF-8", "ISO-8859-1");
+    if (cd_88591_to_utf8 != (iconv_t)(-1))
+      {
+        static ICONV_CONST char input[] = "\304";
+        static char buf[2] = { (char)0xDE, (char)0xAD };
+        ICONV_CONST char *inptr = input;
+        size_t inbytesleft = 1;
+        char *outptr = buf;
+        size_t outbytesleft = 1;
+        size_t res = iconv (cd_88591_to_utf8,
+                            &inptr, &inbytesleft,
+                            &outptr, &outbytesleft);
+        if (res != (size_t)(-1) || outptr - buf > 1 || buf[1] != (char)0xAD)
+          result |= 4;
+        iconv_close (cd_88591_to_utf8);
+      }
+  }
+#if 0 /* This bug could be worked around by the caller.  */
+  /* Test against HP-UX 11.11 bug: Positive return value instead of 0.  */
+  {
+    iconv_t cd_88591_to_utf8 = iconv_open ("utf8", "iso88591");
+    if (cd_88591_to_utf8 != (iconv_t)(-1))
+      {
+        static ICONV_CONST char input[] = "\304rger mit b\366sen B\374bchen ohne Augenma\337";
+        char buf[50];
+        ICONV_CONST char *inptr = input;
+        size_t inbytesleft = strlen (input);
+        char *outptr = buf;
+        size_t outbytesleft = sizeof (buf);
+        size_t res = iconv (cd_88591_to_utf8,
+                            &inptr, &inbytesleft,
+                            &outptr, &outbytesleft);
+        if ((int)res > 0)
+          result |= 8;
+        iconv_close (cd_88591_to_utf8);
+      }
+  }
+#endif
+  /* Test against HP-UX 11.11 bug: No converter from EUC-JP to UTF-8 is
+     provided.  */
+  {
+    /* Try standardized names.  */
+    iconv_t cd1 = iconv_open ("UTF-8", "EUC-JP");
+    /* Try IRIX, OSF/1 names.  */
+    iconv_t cd2 = iconv_open ("UTF-8", "eucJP");
+    /* Try AIX names.  */
+    iconv_t cd3 = iconv_open ("UTF-8", "IBM-eucJP");
+    /* Try HP-UX names.  */
+    iconv_t cd4 = iconv_open ("utf8", "eucJP");
+    if (cd1 == (iconv_t)(-1) && cd2 == (iconv_t)(-1)
+        && cd3 == (iconv_t)(-1) && cd4 == (iconv_t)(-1))
+      result |= 16;
+    if (cd1 != (iconv_t)(-1))
+      iconv_close (cd1);
+    if (cd2 != (iconv_t)(-1))
+      iconv_close (cd2);
+    if (cd3 != (iconv_t)(-1))
+      iconv_close (cd3);
+    if (cd4 != (iconv_t)(-1))
+      iconv_close (cd4);
+  }
+  return result;
+]])],
+          [am_cv_func_iconv_works=yes], ,
+          [case "$host_os" in
+             aix* | hpux*) am_cv_func_iconv_works="guessing no" ;;
+             *)            am_cv_func_iconv_works="guessing yes" ;;
+           esac])
+        test "$am_cv_func_iconv_works" = no || break
+      done
+      LIBS="$am_save_LIBS"
+    ])
+    case "$am_cv_func_iconv_works" in
+      *no) am_func_iconv=no am_cv_lib_iconv=no ;;
+      *)   am_func_iconv=yes ;;
+    esac
+  else
+    am_func_iconv=no am_cv_lib_iconv=no
+  fi
+  if test "$am_func_iconv" = yes; then
+    AC_DEFINE([HAVE_ICONV], [1],
+      [Define if you have the iconv() function and it works.])
+  fi
+  if test "$am_cv_lib_iconv" = yes; then
+    AC_MSG_CHECKING([how to link with libiconv])
+    AC_MSG_RESULT([$LIBICONV])
+  else
+    dnl If $LIBICONV didn't lead to a usable library, we don't need $INCICONV
+    dnl either.
+    CPPFLAGS="$am_save_CPPFLAGS"
+    LIBICONV=
+    LTLIBICONV=
+  fi
+  AC_SUBST([LIBICONV])
+  AC_SUBST([LTLIBICONV])
+])
+
+dnl Define AM_ICONV using AC_DEFUN_ONCE, in order to avoid warnings like
+dnl "warning: AC_REQUIRE: `AM_ICONV' was expanded before it was required".
+dnl This is tricky because of the way 'aclocal' is implemented:
+dnl - It requires defining an auxiliary macro whose name ends in AC_DEFUN.
+dnl   Otherwise aclocal's initial scan pass would miss the macro definition.
+dnl - It requires a line break inside the AC_DEFUN_ONCE and AC_DEFUN expansions.
+dnl   Otherwise aclocal would emit many "Use of uninitialized value $1"
+dnl   warnings.
+AC_DEFUN_ONCE([AM_ICONV],
+[
+  AM_ICONV_LINK
+  if test "$am_cv_func_iconv" = yes; then
+    AC_CACHE_CHECK([whether iconv is compatible with its POSIX signature],
+      [gl_cv_iconv_nonconst],
+      [AC_COMPILE_IFELSE(
+         [AC_LANG_PROGRAM(
+            [[
+#include <stdlib.h>
+#include <iconv.h>
+extern
+#ifdef __cplusplus
+"C"
+#endif
+size_t iconv (iconv_t cd, char * *inbuf, size_t *inbytesleft, char * *outbuf, size_t *outbytesleft);
+            ]],
+            [[]])],
+         [gl_cv_iconv_nonconst=yes],
+         [gl_cv_iconv_nonconst=no])
+      ])
+  else
+    dnl When compiling GNU libiconv on a system that does not have iconv yet,
+    dnl pick the POSIX compliant declaration without 'const'.
+    gl_cv_iconv_nonconst=yes
+  fi
+  if test $gl_cv_iconv_nonconst = yes; then
+    iconv_arg1=""
+  else
+    iconv_arg1="const"
+  fi
+  AC_DEFINE_UNQUOTED([ICONV_CONST], [$iconv_arg1],
+    [Define as const if the declaration of iconv() needs const.])
+  dnl Also substitute ICONV_CONST in the gnulib generated <iconv.h>.
+  m4_ifdef([gl_ICONV_H_DEFAULTS],
+    [AC_REQUIRE([gl_ICONV_H_DEFAULTS])
+     if test $gl_cv_iconv_nonconst != yes; then
+       ICONV_CONST="const"
+     fi
+    ])
+])
diff --git a/m4/iconv_h.m4 b/m4/iconv_h.m4
new file mode 100644
index 0000000..23d41c9
--- /dev/null
+++ b/m4/iconv_h.m4
@@ -0,0 +1,57 @@
+# iconv_h.m4 serial 12
+dnl Copyright (C) 2007-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_ICONV_H],
+[
+  AC_REQUIRE([gl_ICONV_H_DEFAULTS])
+
+  dnl Execute this unconditionally, because ICONV_H may be set by other
+  dnl modules, after this code is executed.
+  gl_CHECK_NEXT_HEADERS([iconv.h])
+
+  dnl Check for declarations of anything we want to poison if the
+  dnl corresponding gnulib module is not in use, and which is not
+  dnl guaranteed by C89.
+  gl_WARN_ON_USE_PREPARE([[#include <iconv.h>
+    ]], [iconv iconv_open])
+
+  AC_REQUIRE([AC_C_RESTRICT])
+])
+
+dnl Unconditionally enables the replacement of <iconv.h>.
+AC_DEFUN([gl_REPLACE_ICONV_H],
+[
+  AC_REQUIRE([gl_ICONV_H_DEFAULTS])
+  ICONV_H='iconv.h'
+  AM_CONDITIONAL([GL_GENERATE_ICONV_H], [test -n "$ICONV_H"])
+])
+
+AC_DEFUN([gl_ICONV_MODULE_INDICATOR],
+[
+  dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
+  AC_REQUIRE([gl_ICONV_H_DEFAULTS])
+  gl_MODULE_INDICATOR_SET_VARIABLE([$1])
+])
+
+AC_DEFUN([gl_ICONV_H_DEFAULTS],
+[
+  m4_ifdef([gl_ANSI_CXX], [AC_REQUIRE([gl_ANSI_CXX])])
+  GNULIB_ICONV=0;       AC_SUBST([GNULIB_ICONV])
+  dnl Assume proper GNU behavior unless another module says otherwise.
+  ICONV_CONST=;         AC_SUBST([ICONV_CONST])
+  REPLACE_ICONV=0;      AC_SUBST([REPLACE_ICONV])
+  REPLACE_ICONV_OPEN=0; AC_SUBST([REPLACE_ICONV_OPEN])
+  REPLACE_ICONV_UTF=0;  AC_SUBST([REPLACE_ICONV_UTF])
+  ICONV_H='';           AC_SUBST([ICONV_H])
+  m4_ifdef([gl_POSIXCHECK],
+    [ICONV_H='iconv.h'],
+    [if m4_ifdef([gl_ANSI_CXX], [test "$CXX" != no], [false]); then
+       dnl Override <fnmatch.h> always, to support the C++ GNULIB_NAMESPACE.
+       ICONV_H='iconv.h'
+     fi
+    ])
+  AM_CONDITIONAL([GL_GENERATE_ICONV_H], [test -n "$ICONV_H"])
+])
diff --git a/m4/include_next.m4 b/m4/include_next.m4
new file mode 100644
index 0000000..9221d9f
--- /dev/null
+++ b/m4/include_next.m4
@@ -0,0 +1,224 @@
+# include_next.m4 serial 26
+dnl Copyright (C) 2006-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl From Paul Eggert and Derek Price.
+
+dnl Sets INCLUDE_NEXT, INCLUDE_NEXT_AS_FIRST_DIRECTIVE, PRAGMA_SYSTEM_HEADER,
+dnl and PRAGMA_COLUMNS.
+dnl
+dnl INCLUDE_NEXT expands to 'include_next' if the compiler supports it, or to
+dnl 'include' otherwise.
+dnl
+dnl INCLUDE_NEXT_AS_FIRST_DIRECTIVE expands to 'include_next' if the compiler
+dnl supports it in the special case that it is the first include directive in
+dnl the given file, or to 'include' otherwise.
+dnl
+dnl PRAGMA_SYSTEM_HEADER can be used in files that contain #include_next,
+dnl so as to avoid GCC warnings when the gcc option -pedantic is used.
+dnl '#pragma GCC system_header' has the same effect as if the file was found
+dnl through the include search path specified with '-isystem' options (as
+dnl opposed to the search path specified with '-I' options). Namely, gcc
+dnl does not warn about some things, and on some systems (Solaris and Interix)
+dnl __STDC__ evaluates to 0 instead of to 1. The latter is an undesired side
+dnl effect; we are therefore careful to use 'defined __STDC__' or '1' instead
+dnl of plain '__STDC__'.
+dnl
+dnl PRAGMA_COLUMNS can be used in files that override system header files, so
+dnl as to avoid compilation errors on HP NonStop systems when the gnulib file
+dnl is included by a system header file that does a "#pragma COLUMNS 80" (which
+dnl has the effect of truncating the lines of that file and all files that it
+dnl includes to 80 columns) and the gnulib file has lines longer than 80
+dnl columns.
+
+AC_DEFUN([gl_INCLUDE_NEXT],
+[
+  AC_LANG_PREPROC_REQUIRE()
+  AC_CACHE_CHECK([whether the preprocessor supports include_next],
+    [gl_cv_have_include_next],
+    [rm -rf conftestd1a conftestd1b conftestd2
+     mkdir conftestd1a conftestd1b conftestd2
+     dnl IBM C 9.0, 10.1 (original versions, prior to the 2009-01 updates) on
+     dnl AIX 6.1 support include_next when used as first preprocessor directive
+     dnl in a file, but not when preceded by another include directive. Check
+     dnl for this bug by including <stdio.h>.
+     dnl Additionally, with this same compiler, include_next is a no-op when
+     dnl used in a header file that was included by specifying its absolute
+     dnl file name. Despite these two bugs, include_next is used in the
+     dnl compiler's <math.h>. By virtue of the second bug, we need to use
+     dnl include_next as well in this case.
+     cat <<EOF > conftestd1a/conftest.h
+#define DEFINED_IN_CONFTESTD1
+#include_next <conftest.h>
+#ifdef DEFINED_IN_CONFTESTD2
+int foo;
+#else
+#error "include_next doesn't work"
+#endif
+EOF
+     cat <<EOF > conftestd1b/conftest.h
+#define DEFINED_IN_CONFTESTD1
+#include <stdio.h>
+#include_next <conftest.h>
+#ifdef DEFINED_IN_CONFTESTD2
+int foo;
+#else
+#error "include_next doesn't work"
+#endif
+EOF
+     cat <<EOF > conftestd2/conftest.h
+#ifndef DEFINED_IN_CONFTESTD1
+#error "include_next test doesn't work"
+#endif
+#define DEFINED_IN_CONFTESTD2
+EOF
+     gl_save_CPPFLAGS="$CPPFLAGS"
+     CPPFLAGS="$gl_save_CPPFLAGS -Iconftestd1b -Iconftestd2"
+dnl We intentionally avoid using AC_LANG_SOURCE here.
+     AC_COMPILE_IFELSE([AC_LANG_DEFINES_PROVIDED[#include <conftest.h>]],
+       [gl_cv_have_include_next=yes],
+       [CPPFLAGS="$gl_save_CPPFLAGS -Iconftestd1a -Iconftestd2"
+        AC_COMPILE_IFELSE([AC_LANG_DEFINES_PROVIDED[#include <conftest.h>]],
+          [gl_cv_have_include_next=buggy],
+          [gl_cv_have_include_next=no])
+       ])
+     CPPFLAGS="$gl_save_CPPFLAGS"
+     rm -rf conftestd1a conftestd1b conftestd2
+    ])
+  PRAGMA_SYSTEM_HEADER=
+  if test $gl_cv_have_include_next = yes; then
+    INCLUDE_NEXT=include_next
+    INCLUDE_NEXT_AS_FIRST_DIRECTIVE=include_next
+    if test -n "$GCC"; then
+      PRAGMA_SYSTEM_HEADER='#pragma GCC system_header'
+    fi
+  else
+    if test $gl_cv_have_include_next = buggy; then
+      INCLUDE_NEXT=include
+      INCLUDE_NEXT_AS_FIRST_DIRECTIVE=include_next
+    else
+      INCLUDE_NEXT=include
+      INCLUDE_NEXT_AS_FIRST_DIRECTIVE=include
+    fi
+  fi
+  AC_SUBST([INCLUDE_NEXT])
+  AC_SUBST([INCLUDE_NEXT_AS_FIRST_DIRECTIVE])
+  AC_SUBST([PRAGMA_SYSTEM_HEADER])
+
+  dnl HP NonStop systems, which define __TANDEM, limit the line length
+  dnl after including some system header files.
+  AC_CACHE_CHECK([whether source code line length is unlimited],
+    [gl_cv_source_line_length_unlimited],
+    [AC_EGREP_CPP([choke me],
+       [
+#ifdef __TANDEM
+choke me
+#endif
+       ],
+       [gl_cv_source_line_length_unlimited=no],
+       [gl_cv_source_line_length_unlimited=yes])
+    ])
+  if test $gl_cv_source_line_length_unlimited = no; then
+    PRAGMA_COLUMNS="#pragma COLUMNS 10000"
+  else
+    PRAGMA_COLUMNS=
+  fi
+  AC_SUBST([PRAGMA_COLUMNS])
+])
+
+# gl_CHECK_NEXT_HEADERS(HEADER1 HEADER2 ...)
+# ------------------------------------------
+# For each arg foo.h, if #include_next works, define NEXT_FOO_H to be
+# '<foo.h>'; otherwise define it to be
+# '"///usr/include/foo.h"', or whatever other absolute file name is suitable.
+# Also, if #include_next works as first preprocessing directive in a file,
+# define NEXT_AS_FIRST_DIRECTIVE_FOO_H to be '<foo.h>'; otherwise define it to
+# be
+# '"///usr/include/foo.h"', or whatever other absolute file name is suitable.
+# That way, a header file with the following line:
+#       #@INCLUDE_NEXT@ @NEXT_FOO_H@
+# or
+#       #@INCLUDE_NEXT_AS_FIRST_DIRECTIVE@ @NEXT_AS_FIRST_DIRECTIVE_FOO_H@
+# behaves (after sed substitution) as if it contained
+#       #include_next <foo.h>
+# even if the compiler does not support include_next.
+# The three "///" are to pacify Sun C 5.8, which otherwise would say
+# "warning: #include of /usr/include/... may be non-portable".
+# Use '""', not '<>', so that the /// cannot be confused with a C99 comment.
+# Note: This macro assumes that the header file is not empty after
+# preprocessing, i.e. it does not only define preprocessor macros but also
+# provides some type/enum definitions or function/variable declarations.
+#
+# This macro also checks whether each header exists, by invoking
+# AC_CHECK_HEADERS_ONCE or AC_CHECK_HEADERS on each argument.
+AC_DEFUN([gl_CHECK_NEXT_HEADERS],
+[
+  gl_NEXT_HEADERS_INTERNAL([$1], [check])
+])
+
+# gl_NEXT_HEADERS(HEADER1 HEADER2 ...)
+# ------------------------------------
+# Like gl_CHECK_NEXT_HEADERS, except do not check whether the headers exist.
+# This is suitable for headers like <stddef.h> that are standardized by C89
+# and therefore can be assumed to exist.
+AC_DEFUN([gl_NEXT_HEADERS],
+[
+  gl_NEXT_HEADERS_INTERNAL([$1], [assume])
+])
+
+# The guts of gl_CHECK_NEXT_HEADERS and gl_NEXT_HEADERS.
+AC_DEFUN([gl_NEXT_HEADERS_INTERNAL],
+[
+  AC_REQUIRE([gl_INCLUDE_NEXT])
+  AC_REQUIRE([AC_CANONICAL_HOST])
+
+  m4_if([$2], [check],
+    [AC_CHECK_HEADERS_ONCE([$1])
+    ])
+
+  m4_foreach_w([gl_HEADER_NAME], [$1],
+    [AS_VAR_PUSHDEF([gl_next_header],
+                    [gl_cv_next_]m4_defn([gl_HEADER_NAME]))
+     if test $gl_cv_have_include_next = yes; then
+       AS_VAR_SET([gl_next_header], ['<'gl_HEADER_NAME'>'])
+     else
+       AC_CACHE_CHECK(
+         [absolute name of <]m4_defn([gl_HEADER_NAME])[>],
+         [gl_next_header],
+         [m4_if([$2], [check],
+            [AS_VAR_PUSHDEF([gl_header_exists],
+                            [ac_cv_header_]m4_defn([gl_HEADER_NAME]))
+             if test AS_VAR_GET([gl_header_exists]) = yes; then
+             AS_VAR_POPDEF([gl_header_exists])
+            ])
+           gl_ABSOLUTE_HEADER_ONE(gl_HEADER_NAME)
+           AS_VAR_COPY([gl_header], [gl_cv_absolute_]AS_TR_SH(gl_HEADER_NAME))
+           AS_VAR_SET([gl_next_header], ['"'$gl_header'"'])
+          m4_if([$2], [check],
+            [else
+               AS_VAR_SET([gl_next_header], ['<'gl_HEADER_NAME'>'])
+             fi
+            ])
+         ])
+     fi
+     AC_SUBST(
+       AS_TR_CPP([NEXT_]m4_defn([gl_HEADER_NAME])),
+       [AS_VAR_GET([gl_next_header])])
+     if test $gl_cv_have_include_next = yes || test $gl_cv_have_include_next = buggy; then
+       # INCLUDE_NEXT_AS_FIRST_DIRECTIVE='include_next'
+       gl_next_as_first_directive='<'gl_HEADER_NAME'>'
+     else
+       # INCLUDE_NEXT_AS_FIRST_DIRECTIVE='include'
+       gl_next_as_first_directive=AS_VAR_GET([gl_next_header])
+     fi
+     AC_SUBST(
+       AS_TR_CPP([NEXT_AS_FIRST_DIRECTIVE_]m4_defn([gl_HEADER_NAME])),
+       [$gl_next_as_first_directive])
+     AS_VAR_POPDEF([gl_next_header])])
+])
+
+# Autoconf 2.68 added warnings for our use of AC_COMPILE_IFELSE;
+# this fallback is safe for all earlier autoconf versions.
+m4_define_default([AC_LANG_DEFINES_PROVIDED])
diff --git a/m4/inet_ntop.m4 b/m4/inet_ntop.m4
new file mode 100644
index 0000000..39a6a9b
--- /dev/null
+++ b/m4/inet_ntop.m4
@@ -0,0 +1,70 @@
+# inet_ntop.m4 serial 21
+dnl Copyright (C) 2005-2006, 2008-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_INET_NTOP],
+[
+  AC_REQUIRE([gl_ARPA_INET_H_DEFAULTS])
+
+  dnl Persuade Solaris <arpa/inet.h> to declare inet_ntop.
+  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+
+  AC_REQUIRE([AC_C_RESTRICT])
+
+  dnl Most platforms that provide inet_ntop define it in libc.
+  dnl Solaris 8..10 provide inet_ntop in libnsl instead.
+  dnl Solaris 2.6..7 provide inet_ntop in libresolv instead.
+  dnl Haiku provides it in -lnetwork.
+  dnl Native Windows provides it in -lws2_32 instead, with a declaration in
+  dnl <ws2tcpip.h>, and it uses stdcall calling convention, not cdecl
+  dnl (hence we cannot use AC_CHECK_FUNCS, AC_SEARCH_LIBS to find it).
+  HAVE_INET_NTOP=1
+  INET_NTOP_LIB=
+  gl_PREREQ_SYS_H_WINSOCK2
+  if test $HAVE_WINSOCK2_H = 1; then
+    dnl It needs to be overridden, because the stdcall calling convention
+    dnl is not compliant with POSIX.  Set REPLACE_INET_NTOP in order to avoid
+    dnl a name conflict at the linker level, even though the header file
+    dnl <ws2tcpip.h> declares inet_ntop only if _WIN32_WINNT >= 0x0600.
+    REPLACE_INET_NTOP=1
+    AC_CHECK_DECLS([inet_ntop],,, [[#include <ws2tcpip.h>]])
+    if test $ac_cv_have_decl_inet_ntop = yes; then
+      INET_NTOP_LIB="-lws2_32"
+    else
+      HAVE_DECL_INET_NTOP=0
+    fi
+  else
+    gl_save_LIBS=$LIBS
+    AC_SEARCH_LIBS([inet_ntop], [nsl resolv network], [],
+      [AC_CHECK_FUNCS([inet_ntop])
+       if test $ac_cv_func_inet_ntop = no; then
+         HAVE_INET_NTOP=0
+       fi
+      ])
+    LIBS=$gl_save_LIBS
+
+    if test "$ac_cv_search_inet_ntop" != "no" \
+       && test "$ac_cv_search_inet_ntop" != "none required"; then
+      INET_NTOP_LIB="$ac_cv_search_inet_ntop"
+    fi
+
+    AC_CHECK_HEADERS_ONCE([netdb.h])
+    AC_CHECK_DECLS([inet_ntop],,,
+      [[#include <arpa/inet.h>
+        #if HAVE_NETDB_H
+        # include <netdb.h>
+        #endif
+      ]])
+    if test $ac_cv_have_decl_inet_ntop = no; then
+      HAVE_DECL_INET_NTOP=0
+    fi
+  fi
+  AC_SUBST([INET_NTOP_LIB])
+])
+
+# Prerequisites of lib/inet_ntop.c.
+AC_DEFUN([gl_PREREQ_INET_NTOP], [
+  AC_REQUIRE([gl_SOCKET_FAMILIES])
+])
diff --git a/m4/inline.m4 b/m4/inline.m4
new file mode 100644
index 0000000..0a7cd8b
--- /dev/null
+++ b/m4/inline.m4
@@ -0,0 +1,40 @@
+# inline.m4 serial 4
+dnl Copyright (C) 2006, 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl Test for the 'inline' keyword or equivalent.
+dnl Define 'inline' to a supported equivalent, or to nothing if not supported,
+dnl like AC_C_INLINE does.  Also, define HAVE_INLINE if 'inline' or an
+dnl equivalent is effectively supported, i.e. if the compiler is likely to
+dnl drop unused 'static inline' functions.
+AC_DEFUN([gl_INLINE],
+[
+  AC_REQUIRE([AC_C_INLINE])
+  AC_CACHE_CHECK([whether the compiler generally respects inline],
+    [gl_cv_c_inline_effective],
+    [if test $ac_cv_c_inline = no; then
+       gl_cv_c_inline_effective=no
+     else
+       dnl GCC defines __NO_INLINE__ if not optimizing or if -fno-inline is
+       dnl specified.
+       dnl Use AC_COMPILE_IFELSE here, not AC_EGREP_CPP, because the result
+       dnl depends on optimization flags, which can be in CFLAGS.
+       dnl (AC_EGREP_CPP looks only at the CPPFLAGS.)
+       AC_COMPILE_IFELSE(
+         [AC_LANG_PROGRAM([[]],
+           [[#ifdef __NO_INLINE__
+               #error "inline is not effective"
+             #endif]])],
+         [gl_cv_c_inline_effective=yes],
+         [gl_cv_c_inline_effective=no])
+     fi
+    ])
+  if test $gl_cv_c_inline_effective = yes; then
+    AC_DEFINE([HAVE_INLINE], [1],
+      [Define to 1 if the compiler supports one of the keywords
+       'inline', '__inline__', '__inline' and effectively inlines
+       functions marked as such.])
+  fi
+])
diff --git a/m4/intlmacosx.m4 b/m4/intlmacosx.m4
new file mode 100644
index 0000000..8a045f6
--- /dev/null
+++ b/m4/intlmacosx.m4
@@ -0,0 +1,56 @@
+# intlmacosx.m4 serial 5 (gettext-0.18.2)
+dnl Copyright (C) 2004-2014 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+dnl
+dnl This file can can be used in projects which are not available under
+dnl the GNU General Public License or the GNU Library General Public
+dnl License but which still want to provide support for the GNU gettext
+dnl functionality.
+dnl Please note that the actual code of the GNU gettext library is covered
+dnl by the GNU Library General Public License, and the rest of the GNU
+dnl gettext package package is covered by the GNU General Public License.
+dnl They are *not* in the public domain.
+
+dnl Checks for special options needed on Mac OS X.
+dnl Defines INTL_MACOSX_LIBS.
+AC_DEFUN([gt_INTL_MACOSX],
+[
+  dnl Check for API introduced in Mac OS X 10.2.
+  AC_CACHE_CHECK([for CFPreferencesCopyAppValue],
+    [gt_cv_func_CFPreferencesCopyAppValue],
+    [gt_save_LIBS="$LIBS"
+     LIBS="$LIBS -Wl,-framework -Wl,CoreFoundation"
+     AC_LINK_IFELSE(
+       [AC_LANG_PROGRAM(
+          [[#include <CoreFoundation/CFPreferences.h>]],
+          [[CFPreferencesCopyAppValue(NULL, NULL)]])],
+       [gt_cv_func_CFPreferencesCopyAppValue=yes],
+       [gt_cv_func_CFPreferencesCopyAppValue=no])
+     LIBS="$gt_save_LIBS"])
+  if test $gt_cv_func_CFPreferencesCopyAppValue = yes; then
+    AC_DEFINE([HAVE_CFPREFERENCESCOPYAPPVALUE], [1],
+      [Define to 1 if you have the Mac OS X function CFPreferencesCopyAppValue in the CoreFoundation framework.])
+  fi
+  dnl Check for API introduced in Mac OS X 10.3.
+  AC_CACHE_CHECK([for CFLocaleCopyCurrent], [gt_cv_func_CFLocaleCopyCurrent],
+    [gt_save_LIBS="$LIBS"
+     LIBS="$LIBS -Wl,-framework -Wl,CoreFoundation"
+     AC_LINK_IFELSE(
+       [AC_LANG_PROGRAM(
+          [[#include <CoreFoundation/CFLocale.h>]],
+          [[CFLocaleCopyCurrent();]])],
+       [gt_cv_func_CFLocaleCopyCurrent=yes],
+       [gt_cv_func_CFLocaleCopyCurrent=no])
+     LIBS="$gt_save_LIBS"])
+  if test $gt_cv_func_CFLocaleCopyCurrent = yes; then
+    AC_DEFINE([HAVE_CFLOCALECOPYCURRENT], [1],
+      [Define to 1 if you have the Mac OS X function CFLocaleCopyCurrent in the CoreFoundation framework.])
+  fi
+  INTL_MACOSX_LIBS=
+  if test $gt_cv_func_CFPreferencesCopyAppValue = yes || test $gt_cv_func_CFLocaleCopyCurrent = yes; then
+    INTL_MACOSX_LIBS="-Wl,-framework -Wl,CoreFoundation"
+  fi
+  AC_SUBST([INTL_MACOSX_LIBS])
+])
diff --git a/m4/intmax_t.m4 b/m4/intmax_t.m4
new file mode 100644
index 0000000..72fc8a9
--- /dev/null
+++ b/m4/intmax_t.m4
@@ -0,0 +1,59 @@
+# intmax_t.m4 serial 9
+dnl Copyright (C) 1997-2004, 2006-2007, 2009-2020 Free Software Foundation,
+dnl Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl From Paul Eggert.
+
+AC_PREREQ([2.53])
+
+# Define intmax_t to 'long' or 'long long'
+# if it is not already defined in <stdint.h> or <inttypes.h>.
+
+AC_DEFUN([gl_AC_TYPE_INTMAX_T],
+[
+  dnl For simplicity, we assume that a header file defines 'intmax_t' if and
+  dnl only if it defines 'uintmax_t'.
+  AC_REQUIRE([gl_AC_HEADER_INTTYPES_H])
+  AC_REQUIRE([gl_AC_HEADER_STDINT_H])
+  if test $gl_cv_header_inttypes_h = no && test $gl_cv_header_stdint_h = no; then
+    AC_DEFINE_UNQUOTED([intmax_t], [long long],
+     [Define to long or long long if <inttypes.h> and <stdint.h> don't define.])
+  else
+    AC_DEFINE([HAVE_INTMAX_T], [1],
+      [Define if you have the 'intmax_t' type in <stdint.h> or <inttypes.h>.])
+  fi
+])
+
+dnl An alternative would be to explicitly test for 'intmax_t'.
+
+AC_DEFUN([gt_AC_TYPE_INTMAX_T],
+[
+  AC_REQUIRE([gl_AC_HEADER_INTTYPES_H])
+  AC_REQUIRE([gl_AC_HEADER_STDINT_H])
+  AC_CACHE_CHECK([for intmax_t], [gt_cv_c_intmax_t],
+    [AC_COMPILE_IFELSE(
+       [AC_LANG_PROGRAM(
+          [[
+#include <stddef.h>
+#include <stdlib.h>
+#if HAVE_STDINT_H_WITH_UINTMAX
+#include <stdint.h>
+#endif
+#if HAVE_INTTYPES_H_WITH_UINTMAX
+#include <inttypes.h>
+#endif
+          ]],
+          [[intmax_t x = -1; return !x;]])],
+       [gt_cv_c_intmax_t=yes],
+       [gt_cv_c_intmax_t=no])])
+  if test $gt_cv_c_intmax_t = yes; then
+    AC_DEFINE([HAVE_INTMAX_T], [1],
+      [Define if you have the 'intmax_t' type in <stdint.h> or <inttypes.h>.])
+  else
+    AC_DEFINE_UNQUOTED([intmax_t], [long long],
+     [Define to long or long long if <stdint.h> and <inttypes.h> don't define.])
+  fi
+])
diff --git a/m4/inttypes.m4 b/m4/inttypes.m4
new file mode 100644
index 0000000..84b1654
--- /dev/null
+++ b/m4/inttypes.m4
@@ -0,0 +1,165 @@
+# inttypes.m4 serial 32
+dnl Copyright (C) 2006-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl From Derek Price, Bruno Haible.
+dnl Test whether <inttypes.h> is supported or must be substituted.
+
+AC_DEFUN([gl_INTTYPES_H],
+[
+  AC_REQUIRE([gl_INTTYPES_INCOMPLETE])
+  gl_INTTYPES_PRI_SCN
+])
+
+AC_DEFUN_ONCE([gl_INTTYPES_INCOMPLETE],
+[
+  AC_REQUIRE([gl_STDINT_H])
+  AC_CHECK_HEADERS_ONCE([inttypes.h])
+
+  dnl Override <inttypes.h> always, so that the portability warnings work.
+  AC_REQUIRE([gl_INTTYPES_H_DEFAULTS])
+  gl_CHECK_NEXT_HEADERS([inttypes.h])
+
+  AC_REQUIRE([gl_MULTIARCH])
+
+  dnl Check for declarations of anything we want to poison if the
+  dnl corresponding gnulib module is not in use.
+  gl_WARN_ON_USE_PREPARE([[#include <inttypes.h>
+    ]], [imaxabs imaxdiv strtoimax strtoumax])
+
+  AC_REQUIRE([AC_C_RESTRICT])
+])
+
+# Ensure that the PRI* and SCN* macros are defined appropriately.
+AC_DEFUN([gl_INTTYPES_PRI_SCN],
+[
+  PRIPTR_PREFIX=
+  if test -n "$STDINT_H"; then
+    dnl Using the gnulib <stdint.h>. It defines intptr_t to 'long' or
+    dnl 'long long', depending on _WIN64.
+    AC_COMPILE_IFELSE(
+      [AC_LANG_PROGRAM([[
+         #ifdef _WIN64
+         LLP64
+         #endif
+         ]])
+      ],
+      [PRIPTR_PREFIX='"l"'],
+      [PRIPTR_PREFIX='"ll"'])
+  else
+    dnl Using the system's <stdint.h>.
+    for glpfx in '' l ll I64; do
+      case $glpfx in
+        '')  gltype1='int';;
+        l)   gltype1='long int';;
+        ll)  gltype1='long long int';;
+        I64) gltype1='__int64';;
+      esac
+      AC_COMPILE_IFELSE(
+        [AC_LANG_PROGRAM([[#include <stdint.h>
+           extern intptr_t foo;
+           extern $gltype1 foo;]])],
+        [PRIPTR_PREFIX='"'$glpfx'"'])
+      test -n "$PRIPTR_PREFIX" && break
+    done
+  fi
+  AC_SUBST([PRIPTR_PREFIX])
+
+  gl_INTTYPES_CHECK_LONG_LONG_INT_CONDITION(
+    [INT32_MAX_LT_INTMAX_MAX],
+    [defined INT32_MAX && defined INTMAX_MAX],
+    [INT32_MAX < INTMAX_MAX],
+    [sizeof (int) < sizeof (long long int)])
+  if test $APPLE_UNIVERSAL_BUILD = 0; then
+    gl_INTTYPES_CHECK_LONG_LONG_INT_CONDITION(
+      [INT64_MAX_EQ_LONG_MAX],
+      [defined INT64_MAX],
+      [INT64_MAX == LONG_MAX],
+      [sizeof (long long int) == sizeof (long int)])
+  else
+    INT64_MAX_EQ_LONG_MAX=-1
+  fi
+  gl_INTTYPES_CHECK_LONG_LONG_INT_CONDITION(
+    [UINT32_MAX_LT_UINTMAX_MAX],
+    [defined UINT32_MAX && defined UINTMAX_MAX],
+    [UINT32_MAX < UINTMAX_MAX],
+    [sizeof (unsigned int) < sizeof (unsigned long long int)])
+  if test $APPLE_UNIVERSAL_BUILD = 0; then
+    gl_INTTYPES_CHECK_LONG_LONG_INT_CONDITION(
+      [UINT64_MAX_EQ_ULONG_MAX],
+      [defined UINT64_MAX],
+      [UINT64_MAX == ULONG_MAX],
+      [sizeof (unsigned long long int) == sizeof (unsigned long int)])
+  else
+    UINT64_MAX_EQ_ULONG_MAX=-1
+  fi
+])
+
+# Define the symbol $1 to be 1 if the condition is true, 0 otherwise.
+# If $2 is true, the condition is $3; otherwise if long long int is supported
+# approximate the condition with $4; otherwise, assume the condition is false.
+# The condition should work on all C99 platforms; the approximations should be
+# good enough to work on all practical pre-C99 platforms.
+# $2 is evaluated by the C preprocessor, $3 and $4 as compile-time constants.
+AC_DEFUN([gl_INTTYPES_CHECK_LONG_LONG_INT_CONDITION],
+[
+  AC_CACHE_CHECK([whether $3],
+    [gl_cv_test_$1],
+    [AC_COMPILE_IFELSE(
+       [AC_LANG_PROGRAM(
+          [[/* Work also in C++ mode.  */
+            #define __STDC_LIMIT_MACROS 1
+
+            /* Work if build is not clean.  */
+            #define _GL_JUST_INCLUDE_SYSTEM_STDINT_H
+
+            #include <limits.h>
+            #if HAVE_STDINT_H
+             #include <stdint.h>
+            #endif
+
+            #if $2
+             #define CONDITION ($3)
+            #else
+             #define CONDITION ($4)
+            #endif
+            int test[CONDITION ? 1 : -1];]])],
+       [gl_cv_test_$1=yes],
+       [gl_cv_test_$1=no])])
+  if test $gl_cv_test_$1 = yes; then
+    $1=1;
+  else
+    $1=0;
+  fi
+  AC_SUBST([$1])
+])
+
+AC_DEFUN([gl_INTTYPES_MODULE_INDICATOR],
+[
+  dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
+  AC_REQUIRE([gl_INTTYPES_H_DEFAULTS])
+  gl_MODULE_INDICATOR_SET_VARIABLE([$1])
+])
+
+AC_DEFUN([gl_INTTYPES_H_DEFAULTS],
+[
+  GNULIB_IMAXABS=0;      AC_SUBST([GNULIB_IMAXABS])
+  GNULIB_IMAXDIV=0;      AC_SUBST([GNULIB_IMAXDIV])
+  GNULIB_STRTOIMAX=0;    AC_SUBST([GNULIB_STRTOIMAX])
+  GNULIB_STRTOUMAX=0;    AC_SUBST([GNULIB_STRTOUMAX])
+  dnl Assume proper GNU behavior unless another module says otherwise.
+  HAVE_DECL_IMAXABS=1;   AC_SUBST([HAVE_DECL_IMAXABS])
+  HAVE_DECL_IMAXDIV=1;   AC_SUBST([HAVE_DECL_IMAXDIV])
+  HAVE_DECL_STRTOIMAX=1; AC_SUBST([HAVE_DECL_STRTOIMAX])
+  HAVE_DECL_STRTOUMAX=1; AC_SUBST([HAVE_DECL_STRTOUMAX])
+  HAVE_IMAXDIV_T=1;      AC_SUBST([HAVE_IMAXDIV_T])
+  REPLACE_STRTOIMAX=0;   AC_SUBST([REPLACE_STRTOIMAX])
+  REPLACE_STRTOUMAX=0;   AC_SUBST([REPLACE_STRTOUMAX])
+  INT32_MAX_LT_INTMAX_MAX=1;  AC_SUBST([INT32_MAX_LT_INTMAX_MAX])
+  INT64_MAX_EQ_LONG_MAX='defined _LP64';  AC_SUBST([INT64_MAX_EQ_LONG_MAX])
+  PRIPTR_PREFIX=__PRIPTR_PREFIX;  AC_SUBST([PRIPTR_PREFIX])
+  UINT32_MAX_LT_UINTMAX_MAX=1;  AC_SUBST([UINT32_MAX_LT_UINTMAX_MAX])
+  UINT64_MAX_EQ_ULONG_MAX='defined _LP64';  AC_SUBST([UINT64_MAX_EQ_ULONG_MAX])
+])
diff --git a/m4/inttypes_h.m4 b/m4/inttypes_h.m4
new file mode 100644
index 0000000..ebb5320
--- /dev/null
+++ b/m4/inttypes_h.m4
@@ -0,0 +1,29 @@
+# inttypes_h.m4 serial 10
+dnl Copyright (C) 1997-2004, 2006, 2008-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl From Paul Eggert.
+
+# Define HAVE_INTTYPES_H_WITH_UINTMAX if <inttypes.h> exists,
+# doesn't clash with <sys/types.h>, and declares uintmax_t.
+
+AC_DEFUN([gl_AC_HEADER_INTTYPES_H],
+[
+  AC_CACHE_CHECK([for inttypes.h], [gl_cv_header_inttypes_h],
+    [AC_COMPILE_IFELSE(
+       [AC_LANG_PROGRAM(
+          [[
+#include <sys/types.h>
+#include <inttypes.h>
+          ]],
+          [[uintmax_t i = (uintmax_t) -1; return !i;]])],
+       [gl_cv_header_inttypes_h=yes],
+       [gl_cv_header_inttypes_h=no])])
+  if test $gl_cv_header_inttypes_h = yes; then
+    AC_DEFINE_UNQUOTED([HAVE_INTTYPES_H_WITH_UINTMAX], [1],
+      [Define if <inttypes.h> exists, doesn't clash with <sys/types.h>,
+       and declares uintmax_t. ])
+  fi
+])
diff --git a/m4/ioctl.m4 b/m4/ioctl.m4
new file mode 100644
index 0000000..263aaae
--- /dev/null
+++ b/m4/ioctl.m4
@@ -0,0 +1,44 @@
+# ioctl.m4 serial 5
+dnl Copyright (C) 2008-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_IOCTL],
+[
+  AC_REQUIRE([gl_SYS_IOCTL_H_DEFAULTS])
+  AC_REQUIRE([gl_HEADER_SYS_SOCKET])
+  HAVE_IOCTL=1
+  if test "$ac_cv_header_winsock2_h" = yes; then
+    dnl Even if the 'socket' module is not used here, another part of the
+    dnl application may use it and pass file descriptors that refer to
+    dnl sockets to the ioctl() function. So enable the support for sockets.
+    HAVE_IOCTL=0
+  else
+    AC_CHECK_FUNCS([ioctl])
+    dnl On glibc systems, the second parameter is 'unsigned long int request',
+    dnl not 'int request'. We cannot simply cast the function pointer, but
+    dnl instead need a wrapper.
+    AC_CACHE_CHECK([for ioctl with POSIX signature],
+      [gl_cv_func_ioctl_posix_signature],
+      [AC_COMPILE_IFELSE(
+         [AC_LANG_PROGRAM(
+            [[#include <sys/ioctl.h>
+              /* On some platforms, ioctl() is declared in <unistd.h>.  */
+              #include <unistd.h>
+            ]],
+            [[extern
+              #ifdef __cplusplus
+              "C"
+              #endif
+              int ioctl (int, int, ...);
+            ]])
+         ],
+         [gl_cv_func_ioctl_posix_signature=yes],
+         [gl_cv_func_ioctl_posix_signature=no])
+      ])
+    if test $gl_cv_func_ioctl_posix_signature != yes; then
+      REPLACE_IOCTL=1
+    fi
+  fi
+])
diff --git a/m4/isblank.m4 b/m4/isblank.m4
new file mode 100644
index 0000000..5e1b783
--- /dev/null
+++ b/m4/isblank.m4
@@ -0,0 +1,17 @@
+# isblank.m4 serial 3
+dnl Copyright (C) 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_ISBLANK],
+[
+  dnl Persuade glibc <ctype.h> to declare isblank().
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
+
+  AC_REQUIRE([gl_CTYPE_H_DEFAULTS])
+  AC_CHECK_FUNCS_ONCE([isblank])
+  if test $ac_cv_func_isblank = no; then
+    HAVE_ISBLANK=0
+  fi
+])
diff --git a/m4/iswblank.m4 b/m4/iswblank.m4
new file mode 100644
index 0000000..dd6ed94
--- /dev/null
+++ b/m4/iswblank.m4
@@ -0,0 +1,34 @@
+# iswblank.m4 serial 5
+dnl Copyright (C) 2011-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_ISWBLANK],
+[
+  AC_REQUIRE([gl_WCTYPE_H_DEFAULTS])
+  AC_REQUIRE([gl_WCTYPE_H])
+  dnl Persuade glibc <wctype.h> to declare iswblank().
+  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+  AC_CHECK_FUNCS_ONCE([iswblank])
+  AC_CHECK_DECLS([iswblank], , , [[
+    #include <wchar.h>
+    #include <wctype.h>
+  ]])
+  if test $ac_cv_func_iswblank = no; then
+    HAVE_ISWBLANK=0
+    if test $ac_cv_have_decl_iswblank = yes; then
+      REPLACE_ISWBLANK=1
+    fi
+  fi
+  if test $HAVE_ISWCNTRL = 0 || test $REPLACE_ISWCNTRL = 1; then
+    dnl Redefine all of iswcntrl, ..., towupper in <wctype.h>.
+    :
+  else
+    if test $HAVE_ISWBLANK = 0 || test $REPLACE_ISWBLANK = 1; then
+      dnl Redefine only iswblank.
+      :
+    fi
+  fi
+
+])
diff --git a/m4/iswdigit.m4 b/m4/iswdigit.m4
new file mode 100644
index 0000000..4ad6a42
--- /dev/null
+++ b/m4/iswdigit.m4
@@ -0,0 +1,115 @@
+# iswdigit.m4 serial 2
+dnl Copyright (C) 2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_ISWDIGIT],
+[
+  AC_REQUIRE([gl_WCTYPE_H_DEFAULTS])
+  AC_REQUIRE([gl_WCTYPE_H])
+  AC_REQUIRE([gt_LOCALE_FR])
+  AC_REQUIRE([gt_LOCALE_JA])
+  AC_REQUIRE([gt_LOCALE_FR_UTF8])
+  AC_REQUIRE([gt_LOCALE_ZH_CN])
+
+  if test $HAVE_ISWCNTRL = 0 || test $REPLACE_ISWCNTRL = 1; then
+    dnl <wctype.h> redefines iswdigit already.
+    REPLACE_ISWDIGIT="$REPLACE_ISWCNTRL"
+  else
+    AC_CACHE_CHECK([whether iswdigit is ISO C compliant],
+      [gl_cv_func_iswdigit_works],
+      [
+       dnl Initial guess, used when cross-compiling or when no suitable locale
+       dnl is present.
+changequote(,)dnl
+       case "$host_os" in
+         # Guess no on FreeBSD, NetBSD, Solaris, native Windows.
+         freebsd* | dragonfly* | netbsd* | solaris* | mingw*)
+           gl_cv_func_iswdigit_works="guessing no" ;;
+         # Guess yes otherwise.
+         *) gl_cv_func_iswdigit_works="guessing yes" ;;
+       esac
+changequote([,])dnl
+       if test $LOCALE_FR != none || test $LOCALE_JA != none || test $LOCALE_FR_UTF8 != none || test $LOCALE_ZH_CN != none; then
+         AC_RUN_IFELSE(
+           [AC_LANG_SOURCE([[
+#include <locale.h>
+#include <stdlib.h>
+#include <string.h>
+#include <wchar.h>
+#include <wctype.h>
+
+/* Returns the value of iswdigit for the multibyte character s[0..n-1].  */
+static int
+for_character (const char *s, size_t n)
+{
+  mbstate_t state;
+  wchar_t wc;
+  size_t ret;
+
+  memset (&state, '\0', sizeof (mbstate_t));
+  wc = (wchar_t) 0xBADFACE;
+  ret = mbrtowc (&wc, s, n, &state);
+  if (ret != n)
+    abort ();
+
+  return iswdigit (wc);
+}
+
+int
+main (int argc, char *argv[])
+{
+  int is;
+  int result = 0;
+
+  if (setlocale (LC_ALL, "$LOCALE_FR") != NULL)
+    {
+      /* This fails on mingw, MSVC 14.  */
+      /* U+00B2 SUPERSCRIPT TWO */
+      is = for_character ("\262", 1);
+      if (!(is == 0))
+        result |= 1;
+    }
+  if (setlocale (LC_ALL, "$LOCALE_JA") != NULL)
+    {
+      /* This fails on NetBSD 8.0.  */
+      /* U+FF11 FULLWIDTH DIGIT ONE */
+      is = for_character ("\243\261", 2);
+      if (!(is == 0))
+        result |= 2;
+    }
+  if (setlocale (LC_ALL, "$LOCALE_FR_UTF8") != NULL)
+    {
+      /* This fails on FreeBSD 12, NetBSD 8.0, MSVC 14.  */
+      /* U+0663 ARABIC-INDIC DIGIT THREE */
+      is = for_character ("\331\243", 2);
+      if (!(is == 0))
+        result |= 4;
+      /* This fails on FreeBSD 12, NetBSD 8.0, MSVC 14.  */
+      /* U+FF11 FULLWIDTH DIGIT ONE */
+      is = for_character ("\357\274\221", 3);
+      if (!(is == 0))
+        result |= 8;
+    }
+  if (setlocale (LC_ALL, "$LOCALE_ZH_CN") != NULL)
+    {
+      /* This fails on NetBSD 8.0, Solaris 10, Solaris 11.4.  */
+      /* U+FF11 FULLWIDTH DIGIT ONE */
+      is = for_character ("\243\261", 2);
+      if (!(is == 0))
+        result |= 16;
+    }
+  return result;
+}]])],
+           [gl_cv_func_iswdigit_works=yes],
+           [gl_cv_func_iswdigit_works=no],
+           [:])
+       fi
+      ])
+    case "$gl_cv_func_iswdigit_works" in
+      *yes) ;;
+      *) REPLACE_ISWDIGIT=1 ;;
+    esac
+  fi
+])
diff --git a/m4/iswxdigit.m4 b/m4/iswxdigit.m4
new file mode 100644
index 0000000..c63e81e
--- /dev/null
+++ b/m4/iswxdigit.m4
@@ -0,0 +1,106 @@
+# iswxdigit.m4 serial 2
+dnl Copyright (C) 2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_ISWXDIGIT],
+[
+  AC_REQUIRE([gl_WCTYPE_H_DEFAULTS])
+  AC_REQUIRE([gl_WCTYPE_H])
+  AC_REQUIRE([gt_LOCALE_JA])
+  AC_REQUIRE([gt_LOCALE_FR_UTF8])
+  AC_REQUIRE([gt_LOCALE_ZH_CN])
+
+  if test $HAVE_ISWCNTRL = 0 || test $REPLACE_ISWCNTRL = 1; then
+    dnl <wctype.h> redefines iswxdigit already.
+    REPLACE_ISWXDIGIT="$REPLACE_ISWCNTRL"
+  else
+    AC_CACHE_CHECK([whether iswxdigit is ISO C compliant],
+      [gl_cv_func_iswxdigit_works],
+      [
+       dnl Initial guess, used when cross-compiling or when no suitable locale
+       dnl is present.
+changequote(,)dnl
+       case "$host_os" in
+         # Guess no on FreeBSD, NetBSD, Solaris, native Windows.
+         freebsd* | dragonfly* | netbsd* | solaris* | mingw*)
+           gl_cv_func_iswxdigit_works="guessing no" ;;
+         # Guess yes otherwise.
+         *) gl_cv_func_iswxdigit_works="guessing yes" ;;
+       esac
+changequote([,])dnl
+       if test $LOCALE_JA != none || test $LOCALE_FR_UTF8 != none || test $LOCALE_ZH_CN != none; then
+         AC_RUN_IFELSE(
+           [AC_LANG_SOURCE([[
+#include <locale.h>
+#include <stdlib.h>
+#include <string.h>
+#include <wchar.h>
+#include <wctype.h>
+
+/* Returns the value of iswxdigit for the multibyte character s[0..n-1].  */
+static int
+for_character (const char *s, size_t n)
+{
+  mbstate_t state;
+  wchar_t wc;
+  size_t ret;
+
+  memset (&state, '\0', sizeof (mbstate_t));
+  wc = (wchar_t) 0xBADFACE;
+  ret = mbrtowc (&wc, s, n, &state);
+  if (ret != n)
+    abort ();
+
+  return iswxdigit (wc);
+}
+
+int
+main (int argc, char *argv[])
+{
+  int is;
+  int result = 0;
+
+  if (setlocale (LC_ALL, "$LOCALE_JA") != NULL)
+    {
+      /* This fails on NetBSD 8.0.  */
+      /* U+FF21 FULLWIDTH LATIN CAPITAL LETTER A */
+      is = for_character ("\243\301", 2);
+      if (!(is == 0))
+        result |= 1;
+    }
+  if (setlocale (LC_ALL, "$LOCALE_FR_UTF8") != NULL)
+    {
+      /* This fails on FreeBSD 12.  */
+      /* U+0663 ARABIC-INDIC DIGIT THREE */
+      is = for_character ("\331\243", 2);
+      if (!(is == 0))
+        result |= 2;
+      /* This fails on MSVC 14.  */
+      /* U+FF21 FULLWIDTH LATIN CAPITAL LETTER A */
+      is = for_character ("\357\274\241", 3);
+      if (!(is == 0))
+        result |= 4;
+    }
+  if (setlocale (LC_ALL, "$LOCALE_ZH_CN") != NULL)
+    {
+      /* This fails on Solaris 10, Solaris 11.4.  */
+      /* U+FF11 FULLWIDTH DIGIT ONE */
+      is = for_character ("\243\261", 2);
+      if (!(is == 0))
+        result |= 8;
+    }
+  return result;
+}]])],
+           [gl_cv_func_iswxdigit_works=yes],
+           [gl_cv_func_iswxdigit_works=no],
+           [:])
+       fi
+      ])
+    case "$gl_cv_func_iswxdigit_works" in
+      *yes) ;;
+      *) REPLACE_ISWXDIGIT=1 ;;
+    esac
+  fi
+])
diff --git a/m4/langinfo_h.m4 b/m4/langinfo_h.m4
new file mode 100644
index 0000000..9d5e16e
--- /dev/null
+++ b/m4/langinfo_h.m4
@@ -0,0 +1,122 @@
+# langinfo_h.m4 serial 9
+dnl Copyright (C) 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_LANGINFO_H],
+[
+  AC_REQUIRE([gl_LANGINFO_H_DEFAULTS])
+
+  dnl Persuade glibc-2.0.6 <langinfo.h> to define CODESET.
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
+
+  dnl <langinfo.h> is always overridden, because of GNULIB_POSIXCHECK.
+  gl_CHECK_NEXT_HEADERS([langinfo.h])
+
+  dnl Determine whether <langinfo.h> exists. It is missing on mingw and BeOS.
+  HAVE_LANGINFO_CODESET=0
+  HAVE_LANGINFO_T_FMT_AMPM=0
+  HAVE_LANGINFO_ALTMON=0
+  HAVE_LANGINFO_ERA=0
+  HAVE_LANGINFO_YESEXPR=0
+  AC_CHECK_HEADERS_ONCE([langinfo.h])
+  if test $ac_cv_header_langinfo_h = yes; then
+    HAVE_LANGINFO_H=1
+    dnl Determine what <langinfo.h> defines.
+    dnl CODESET is missing on OpenBSD 3.8.
+    dnl ERA etc. are missing on OpenBSD 6.7.
+    dnl T_FMT_AMPM and YESEXPR, NOEXPR are missing on IRIX 5.3.
+    dnl ALTMON_* are missing on glibc 2.26 and many other systems.
+    AC_CACHE_CHECK([whether langinfo.h defines CODESET],
+      [gl_cv_header_langinfo_codeset],
+      [AC_COMPILE_IFELSE(
+         [AC_LANG_PROGRAM([[#include <langinfo.h>
+int a = CODESET;
+]])],
+         [gl_cv_header_langinfo_codeset=yes],
+         [gl_cv_header_langinfo_codeset=no])
+      ])
+    if test $gl_cv_header_langinfo_codeset = yes; then
+      HAVE_LANGINFO_CODESET=1
+    fi
+    AC_CACHE_CHECK([whether langinfo.h defines T_FMT_AMPM],
+      [gl_cv_header_langinfo_t_fmt_ampm],
+      [AC_COMPILE_IFELSE(
+         [AC_LANG_PROGRAM([[#include <langinfo.h>
+int a = T_FMT_AMPM;
+]])],
+         [gl_cv_header_langinfo_t_fmt_ampm=yes],
+         [gl_cv_header_langinfo_t_fmt_ampm=no])
+      ])
+    if test $gl_cv_header_langinfo_t_fmt_ampm = yes; then
+      HAVE_LANGINFO_T_FMT_AMPM=1
+    fi
+    AC_CACHE_CHECK([whether langinfo.h defines ALTMON_1],
+      [gl_cv_header_langinfo_altmon],
+      [AC_COMPILE_IFELSE(
+         [AC_LANG_PROGRAM([[#include <langinfo.h>
+int a = ALTMON_1;
+]])],
+         [gl_cv_header_langinfo_altmon=yes],
+         [gl_cv_header_langinfo_altmon=no])
+      ])
+    if test $gl_cv_header_langinfo_altmon = yes; then
+      HAVE_LANGINFO_ALTMON=1
+    fi
+    AC_CACHE_CHECK([whether langinfo.h defines ERA],
+      [gl_cv_header_langinfo_era],
+      [AC_COMPILE_IFELSE(
+         [AC_LANG_PROGRAM([[#include <langinfo.h>
+int a = ERA;
+]])],
+         [gl_cv_header_langinfo_era=yes],
+         [gl_cv_header_langinfo_era=no])
+      ])
+    if test $gl_cv_header_langinfo_era = yes; then
+      HAVE_LANGINFO_ERA=1
+    fi
+    AC_CACHE_CHECK([whether langinfo.h defines YESEXPR],
+      [gl_cv_header_langinfo_yesexpr],
+      [AC_COMPILE_IFELSE(
+         [AC_LANG_PROGRAM([[#include <langinfo.h>
+int a = YESEXPR;
+]])],
+         [gl_cv_header_langinfo_yesexpr=yes],
+         [gl_cv_header_langinfo_yesexpr=no])
+      ])
+    if test $gl_cv_header_langinfo_yesexpr = yes; then
+      HAVE_LANGINFO_YESEXPR=1
+    fi
+  else
+    HAVE_LANGINFO_H=0
+  fi
+  AC_SUBST([HAVE_LANGINFO_H])
+  AC_SUBST([HAVE_LANGINFO_CODESET])
+  AC_SUBST([HAVE_LANGINFO_T_FMT_AMPM])
+  AC_SUBST([HAVE_LANGINFO_ALTMON])
+  AC_SUBST([HAVE_LANGINFO_ERA])
+  AC_SUBST([HAVE_LANGINFO_YESEXPR])
+
+  dnl Check for declarations of anything we want to poison if the
+  dnl corresponding gnulib module is not in use.
+  gl_WARN_ON_USE_PREPARE([[#include <langinfo.h>
+    ]], [nl_langinfo])
+])
+
+AC_DEFUN([gl_LANGINFO_MODULE_INDICATOR],
+[
+  dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
+  AC_REQUIRE([gl_LANGINFO_H_DEFAULTS])
+  gl_MODULE_INDICATOR_SET_VARIABLE([$1])
+  dnl Define it also as a C macro, for the benefit of the unit tests.
+  gl_MODULE_INDICATOR_FOR_TESTS([$1])
+])
+
+AC_DEFUN([gl_LANGINFO_H_DEFAULTS],
+[
+  GNULIB_NL_LANGINFO=0;  AC_SUBST([GNULIB_NL_LANGINFO])
+  dnl Assume proper GNU behavior unless another module says otherwise.
+  HAVE_NL_LANGINFO=1;    AC_SUBST([HAVE_NL_LANGINFO])
+  REPLACE_NL_LANGINFO=0; AC_SUBST([REPLACE_NL_LANGINFO])
+])
diff --git a/m4/largefile.m4 b/m4/largefile.m4
new file mode 100644
index 0000000..c4cc835
--- /dev/null
+++ b/m4/largefile.m4
@@ -0,0 +1,178 @@
+# Enable large files on systems where this is not the default.
+# Enable support for files on Linux file systems with 64-bit inode numbers.
+
+# Copyright 1992-1996, 1998-2020 Free Software Foundation, Inc.
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+# The following macro works around a problem in Autoconf's AC_FUNC_FSEEKO:
+# It does not set _LARGEFILE_SOURCE=1 on HP-UX/ia64 32-bit, although this
+# setting of _LARGEFILE_SOURCE is needed so that <stdio.h> declares fseeko
+# and ftello in C++ mode as well.
+AC_DEFUN([gl_SET_LARGEFILE_SOURCE],
+[
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  AC_FUNC_FSEEKO
+  case "$host_os" in
+    hpux*)
+      AC_DEFINE([_LARGEFILE_SOURCE], [1],
+        [Define to 1 to make fseeko visible on some hosts (e.g. glibc 2.2).])
+      ;;
+  esac
+])
+
+# The following implementation works around a problem in autoconf <= 2.69;
+# AC_SYS_LARGEFILE does not configure for large inodes on Mac OS X 10.5,
+# or configures them incorrectly in some cases.
+m4_version_prereq([2.70], [], [
+
+# _AC_SYS_LARGEFILE_TEST_INCLUDES
+# -------------------------------
+m4_define([_AC_SYS_LARGEFILE_TEST_INCLUDES],
+[#include <sys/types.h>
+ /* Check that off_t can represent 2**63 - 1 correctly.
+    We can't simply define LARGE_OFF_T to be 9223372036854775807,
+    since some C++ compilers masquerading as C compilers
+    incorrectly reject 9223372036854775807.  */
+#define LARGE_OFF_T (((off_t) 1 << 31 << 31) - 1 + ((off_t) 1 << 31 << 31))
+  int off_t_is_large[[(LARGE_OFF_T % 2147483629 == 721
+                       && LARGE_OFF_T % 2147483647 == 1)
+                      ? 1 : -1]];[]dnl
+])
+
+
+# _AC_SYS_LARGEFILE_MACRO_VALUE(C-MACRO, VALUE,
+#                               CACHE-VAR,
+#                               DESCRIPTION,
+#                               PROLOGUE, [FUNCTION-BODY])
+# --------------------------------------------------------
+m4_define([_AC_SYS_LARGEFILE_MACRO_VALUE],
+[AC_CACHE_CHECK([for $1 value needed for large files], [$3],
+[while :; do
+  m4_ifval([$6], [AC_LINK_IFELSE], [AC_COMPILE_IFELSE])(
+    [AC_LANG_PROGRAM([$5], [$6])],
+    [$3=no; break])
+  m4_ifval([$6], [AC_LINK_IFELSE], [AC_COMPILE_IFELSE])(
+    [AC_LANG_PROGRAM([#define $1 $2
+$5], [$6])],
+    [$3=$2; break])
+  $3=unknown
+  break
+done])
+case $$3 in #(
+  no | unknown) ;;
+  *) AC_DEFINE_UNQUOTED([$1], [$$3], [$4]);;
+esac
+rm -rf conftest*[]dnl
+])# _AC_SYS_LARGEFILE_MACRO_VALUE
+
+
+# AC_SYS_LARGEFILE
+# ----------------
+# By default, many hosts won't let programs access large files;
+# one must use special compiler options to get large-file access to work.
+# For more details about this brain damage please see:
+# http://www.unix.org/version2/whatsnew/lfs20mar.html
+# Additionally, on Linux file systems with 64-bit inodes a file that happens
+# to have a 64-bit inode number cannot be accessed by 32-bit applications on
+# Linux x86/x86_64.  This can occur with file systems such as XFS and NFS.
+AC_DEFUN([AC_SYS_LARGEFILE],
+[AC_ARG_ENABLE(largefile,
+               [  --disable-largefile     omit support for large files])
+if test "$enable_largefile" != no; then
+
+  AC_CACHE_CHECK([for special C compiler options needed for large files],
+    ac_cv_sys_largefile_CC,
+    [ac_cv_sys_largefile_CC=no
+     if test "$GCC" != yes; then
+       ac_save_CC=$CC
+       while :; do
+         # IRIX 6.2 and later do not support large files by default,
+         # so use the C compiler's -n32 option if that helps.
+         AC_LANG_CONFTEST([AC_LANG_PROGRAM([_AC_SYS_LARGEFILE_TEST_INCLUDES])])
+         AC_COMPILE_IFELSE([], [break])
+         CC="$CC -n32"
+         AC_COMPILE_IFELSE([], [ac_cv_sys_largefile_CC=' -n32'; break])
+         break
+       done
+       CC=$ac_save_CC
+       rm -f conftest.$ac_ext
+    fi])
+  if test "$ac_cv_sys_largefile_CC" != no; then
+    CC=$CC$ac_cv_sys_largefile_CC
+  fi
+
+  _AC_SYS_LARGEFILE_MACRO_VALUE(_FILE_OFFSET_BITS, 64,
+    ac_cv_sys_file_offset_bits,
+    [Number of bits in a file offset, on hosts where this is settable.],
+    [_AC_SYS_LARGEFILE_TEST_INCLUDES])
+  if test $ac_cv_sys_file_offset_bits = unknown; then
+    _AC_SYS_LARGEFILE_MACRO_VALUE(_LARGE_FILES, 1,
+      ac_cv_sys_large_files,
+      [Define for large files, on AIX-style hosts.],
+      [_AC_SYS_LARGEFILE_TEST_INCLUDES])
+  fi
+fi
+])# AC_SYS_LARGEFILE
+])# m4_version_prereq 2.70
+
+# Enable large files on systems where this is implemented by Gnulib, not by the
+# system headers.
+# Set the variables WINDOWS_64_BIT_OFF_T, WINDOWS_64_BIT_ST_SIZE if Gnulib
+# overrides ensure that off_t or 'struct size.st_size' are 64-bit, respectively.
+AC_DEFUN([gl_LARGEFILE],
+[
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  case "$host_os" in
+    mingw*)
+      dnl Native Windows.
+      dnl mingw64 defines off_t to a 64-bit type already, if
+      dnl _FILE_OFFSET_BITS=64, which is ensured by AC_SYS_LARGEFILE.
+      AC_CACHE_CHECK([for 64-bit off_t], [gl_cv_type_off_t_64],
+        [AC_COMPILE_IFELSE(
+           [AC_LANG_PROGRAM(
+              [[#include <sys/types.h>
+                int verify_off_t_size[sizeof (off_t) >= 8 ? 1 : -1];
+              ]],
+              [[]])],
+           [gl_cv_type_off_t_64=yes], [gl_cv_type_off_t_64=no])
+        ])
+      if test $gl_cv_type_off_t_64 = no; then
+        WINDOWS_64_BIT_OFF_T=1
+      else
+        WINDOWS_64_BIT_OFF_T=0
+      fi
+      dnl Some mingw versions define, if _FILE_OFFSET_BITS=64, 'struct stat'
+      dnl to 'struct _stat32i64' or 'struct _stat64' (depending on
+      dnl _USE_32BIT_TIME_T), which has a 32-bit st_size member.
+      AC_CACHE_CHECK([for 64-bit st_size], [gl_cv_member_st_size_64],
+        [AC_COMPILE_IFELSE(
+           [AC_LANG_PROGRAM(
+              [[#include <sys/types.h>
+                struct stat buf;
+                int verify_st_size_size[sizeof (buf.st_size) >= 8 ? 1 : -1];
+              ]],
+              [[]])],
+           [gl_cv_member_st_size_64=yes], [gl_cv_member_st_size_64=no])
+        ])
+      if test $gl_cv_member_st_size_64 = no; then
+        WINDOWS_64_BIT_ST_SIZE=1
+      else
+        WINDOWS_64_BIT_ST_SIZE=0
+      fi
+      ;;
+    *)
+      dnl Nothing to do on gnulib's side.
+      dnl A 64-bit off_t is
+      dnl   - already the default on Mac OS X, FreeBSD, NetBSD, OpenBSD, IRIX,
+      dnl     OSF/1, Cygwin,
+      dnl   - enabled by _FILE_OFFSET_BITS=64 (ensured by AC_SYS_LARGEFILE) on
+      dnl     glibc, HP-UX, Solaris,
+      dnl   - enabled by _LARGE_FILES=1 (ensured by AC_SYS_LARGEFILE) on AIX,
+      dnl   - impossible to achieve on Minix 3.1.8.
+      WINDOWS_64_BIT_OFF_T=0
+      WINDOWS_64_BIT_ST_SIZE=0
+      ;;
+  esac
+])
diff --git a/m4/lib-ld.m4 b/m4/lib-ld.m4
new file mode 100644
index 0000000..98c348f
--- /dev/null
+++ b/m4/lib-ld.m4
@@ -0,0 +1,168 @@
+# lib-ld.m4 serial 9
+dnl Copyright (C) 1996-2003, 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl Subroutines of libtool.m4,
+dnl with replacements s/_*LT_PATH/AC_LIB_PROG/ and s/lt_/acl_/ to avoid
+dnl collision with libtool.m4.
+
+dnl From libtool-2.4. Sets the variable with_gnu_ld to yes or no.
+AC_DEFUN([AC_LIB_PROG_LD_GNU],
+[AC_CACHE_CHECK([if the linker ($LD) is GNU ld], [acl_cv_prog_gnu_ld],
+[# I'd rather use --version here, but apparently some GNU lds only accept -v.
+case `$LD -v 2>&1 </dev/null` in
+*GNU* | *'with BFD'*)
+  acl_cv_prog_gnu_ld=yes
+  ;;
+*)
+  acl_cv_prog_gnu_ld=no
+  ;;
+esac])
+with_gnu_ld=$acl_cv_prog_gnu_ld
+])
+
+dnl From libtool-2.4. Sets the variable LD.
+AC_DEFUN([AC_LIB_PROG_LD],
+[AC_REQUIRE([AC_PROG_CC])dnl
+AC_REQUIRE([AC_CANONICAL_HOST])dnl
+
+AC_ARG_WITH([gnu-ld],
+    [AS_HELP_STRING([--with-gnu-ld],
+        [assume the C compiler uses GNU ld [default=no]])],
+    [test "$withval" = no || with_gnu_ld=yes],
+    [with_gnu_ld=no])dnl
+
+# Prepare PATH_SEPARATOR.
+# The user is always right.
+if test "${PATH_SEPARATOR+set}" != set; then
+  # Determine PATH_SEPARATOR by trying to find /bin/sh in a PATH which
+  # contains only /bin. Note that ksh looks also at the FPATH variable,
+  # so we have to set that as well for the test.
+  PATH_SEPARATOR=:
+  (PATH='/bin;/bin'; FPATH=$PATH; sh -c :) >/dev/null 2>&1 \
+    && { (PATH='/bin:/bin'; FPATH=$PATH; sh -c :) >/dev/null 2>&1 \
+           || PATH_SEPARATOR=';'
+       }
+fi
+
+if test -n "$LD"; then
+  AC_MSG_CHECKING([for ld])
+elif test "$GCC" = yes; then
+  AC_MSG_CHECKING([for ld used by $CC])
+elif test "$with_gnu_ld" = yes; then
+  AC_MSG_CHECKING([for GNU ld])
+else
+  AC_MSG_CHECKING([for non-GNU ld])
+fi
+if test -n "$LD"; then
+  # Let the user override the test with a path.
+  :
+else
+  AC_CACHE_VAL([acl_cv_path_LD],
+  [
+    acl_cv_path_LD= # Final result of this test
+    ac_prog=ld # Program to search in $PATH
+    if test "$GCC" = yes; then
+      # Check if gcc -print-prog-name=ld gives a path.
+      case $host in
+        *-*-mingw*)
+          # gcc leaves a trailing carriage return which upsets mingw
+          acl_output=`($CC -print-prog-name=ld) 2>&5 | tr -d '\015'` ;;
+        *)
+          acl_output=`($CC -print-prog-name=ld) 2>&5` ;;
+      esac
+      case $acl_output in
+        # Accept absolute paths.
+        [[\\/]]* | ?:[[\\/]]*)
+          re_direlt='/[[^/]][[^/]]*/\.\./'
+          # Canonicalize the pathname of ld
+          acl_output=`echo "$acl_output" | sed 's%\\\\%/%g'`
+          while echo "$acl_output" | grep "$re_direlt" > /dev/null 2>&1; do
+            acl_output=`echo $acl_output | sed "s%$re_direlt%/%"`
+          done
+          # Got the pathname. No search in PATH is needed.
+          acl_cv_path_LD="$acl_output"
+          ac_prog=
+          ;;
+        "")
+          # If it fails, then pretend we aren't using GCC.
+          ;;
+        *)
+          # If it is relative, then search for the first ld in PATH.
+          with_gnu_ld=unknown
+          ;;
+      esac
+    fi
+    if test -n "$ac_prog"; then
+      # Search for $ac_prog in $PATH.
+      acl_save_ifs="$IFS"; IFS=$PATH_SEPARATOR
+      for ac_dir in $PATH; do
+        IFS="$acl_save_ifs"
+        test -z "$ac_dir" && ac_dir=.
+        if test -f "$ac_dir/$ac_prog" || test -f "$ac_dir/$ac_prog$ac_exeext"; then
+          acl_cv_path_LD="$ac_dir/$ac_prog"
+          # Check to see if the program is GNU ld.  I'd rather use --version,
+          # but apparently some variants of GNU ld only accept -v.
+          # Break only if it was the GNU/non-GNU ld that we prefer.
+          case `"$acl_cv_path_LD" -v 2>&1 </dev/null` in
+            *GNU* | *'with BFD'*)
+              test "$with_gnu_ld" != no && break
+              ;;
+            *)
+              test "$with_gnu_ld" != yes && break
+              ;;
+          esac
+        fi
+      done
+      IFS="$acl_save_ifs"
+    fi
+    case $host in
+      *-*-aix*)
+        AC_COMPILE_IFELSE(
+          [AC_LANG_SOURCE(
+             [[#if defined __powerpc64__ || defined _ARCH_PPC64
+                int ok;
+               #else
+                error fail
+               #endif
+             ]])],
+          [# The compiler produces 64-bit code. Add option '-b64' so that the
+           # linker groks 64-bit object files.
+           case "$acl_cv_path_LD " in
+             *" -b64 "*) ;;
+             *) acl_cv_path_LD="$acl_cv_path_LD -b64" ;;
+           esac
+          ], [])
+        ;;
+      sparc64-*-netbsd*)
+        AC_COMPILE_IFELSE(
+          [AC_LANG_SOURCE(
+             [[#if defined __sparcv9 || defined __arch64__
+                int ok;
+               #else
+                error fail
+               #endif
+             ]])],
+          [],
+          [# The compiler produces 32-bit code. Add option '-m elf32_sparc'
+           # so that the linker groks 32-bit object files.
+           case "$acl_cv_path_LD " in
+             *" -m elf32_sparc "*) ;;
+             *) acl_cv_path_LD="$acl_cv_path_LD -m elf32_sparc" ;;
+           esac
+          ])
+        ;;
+    esac
+  ])
+  LD="$acl_cv_path_LD"
+fi
+if test -n "$LD"; then
+  AC_MSG_RESULT([$LD])
+else
+  AC_MSG_RESULT([no])
+  AC_MSG_ERROR([no acceptable ld found in \$PATH])
+fi
+AC_LIB_PROG_LD_GNU
+])
diff --git a/m4/lib-link.m4 b/m4/lib-link.m4
new file mode 100644
index 0000000..5ce1aa2
--- /dev/null
+++ b/m4/lib-link.m4
@@ -0,0 +1,813 @@
+# lib-link.m4 serial 32
+dnl Copyright (C) 2001-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl From Bruno Haible.
+
+AC_PREREQ([2.61])
+
+dnl AC_LIB_LINKFLAGS(name [, dependencies]) searches for libname and
+dnl the libraries corresponding to explicit and implicit dependencies.
+dnl Sets and AC_SUBSTs the LIB${NAME} and LTLIB${NAME} variables and
+dnl augments the CPPFLAGS variable.
+dnl Sets and AC_SUBSTs the LIB${NAME}_PREFIX variable to nonempty if libname
+dnl was found in ${LIB${NAME}_PREFIX}/$acl_libdirstem.
+AC_DEFUN([AC_LIB_LINKFLAGS],
+[
+  AC_REQUIRE([AC_LIB_PREPARE_PREFIX])
+  AC_REQUIRE([AC_LIB_RPATH])
+  pushdef([Name],[m4_translit([$1],[./+-], [____])])
+  pushdef([NAME],[m4_translit([$1],[abcdefghijklmnopqrstuvwxyz./+-],
+                                   [ABCDEFGHIJKLMNOPQRSTUVWXYZ____])])
+  AC_CACHE_CHECK([how to link with lib[]$1], [ac_cv_lib[]Name[]_libs], [
+    AC_LIB_LINKFLAGS_BODY([$1], [$2])
+    ac_cv_lib[]Name[]_libs="$LIB[]NAME"
+    ac_cv_lib[]Name[]_ltlibs="$LTLIB[]NAME"
+    ac_cv_lib[]Name[]_cppflags="$INC[]NAME"
+    ac_cv_lib[]Name[]_prefix="$LIB[]NAME[]_PREFIX"
+  ])
+  LIB[]NAME="$ac_cv_lib[]Name[]_libs"
+  LTLIB[]NAME="$ac_cv_lib[]Name[]_ltlibs"
+  INC[]NAME="$ac_cv_lib[]Name[]_cppflags"
+  LIB[]NAME[]_PREFIX="$ac_cv_lib[]Name[]_prefix"
+  AC_LIB_APPENDTOVAR([CPPFLAGS], [$INC]NAME)
+  AC_SUBST([LIB]NAME)
+  AC_SUBST([LTLIB]NAME)
+  AC_SUBST([LIB]NAME[_PREFIX])
+  dnl Also set HAVE_LIB[]NAME so that AC_LIB_HAVE_LINKFLAGS can reuse the
+  dnl results of this search when this library appears as a dependency.
+  HAVE_LIB[]NAME=yes
+  popdef([NAME])
+  popdef([Name])
+])
+
+dnl AC_LIB_HAVE_LINKFLAGS(name, dependencies, includes, testcode, [missing-message])
+dnl searches for libname and the libraries corresponding to explicit and
+dnl implicit dependencies, together with the specified include files and
+dnl the ability to compile and link the specified testcode. The missing-message
+dnl defaults to 'no' and may contain additional hints for the user.
+dnl If found, it sets and AC_SUBSTs HAVE_LIB${NAME}=yes and the LIB${NAME}
+dnl and LTLIB${NAME} variables and augments the CPPFLAGS variable, and
+dnl #defines HAVE_LIB${NAME} to 1. Otherwise, it sets and AC_SUBSTs
+dnl HAVE_LIB${NAME}=no and LIB${NAME} and LTLIB${NAME} to empty.
+dnl Sets and AC_SUBSTs the LIB${NAME}_PREFIX variable to nonempty if libname
+dnl was found in ${LIB${NAME}_PREFIX}/$acl_libdirstem.
+AC_DEFUN([AC_LIB_HAVE_LINKFLAGS],
+[
+  AC_REQUIRE([AC_LIB_PREPARE_PREFIX])
+  AC_REQUIRE([AC_LIB_RPATH])
+  pushdef([Name],[m4_translit([$1],[./+-], [____])])
+  pushdef([NAME],[m4_translit([$1],[abcdefghijklmnopqrstuvwxyz./+-],
+                                   [ABCDEFGHIJKLMNOPQRSTUVWXYZ____])])
+
+  dnl Search for lib[]Name and define LIB[]NAME, LTLIB[]NAME and INC[]NAME
+  dnl accordingly.
+  AC_LIB_LINKFLAGS_BODY([$1], [$2])
+
+  dnl Add $INC[]NAME to CPPFLAGS before performing the following checks,
+  dnl because if the user has installed lib[]Name and not disabled its use
+  dnl via --without-lib[]Name-prefix, he wants to use it.
+  ac_save_CPPFLAGS="$CPPFLAGS"
+  AC_LIB_APPENDTOVAR([CPPFLAGS], [$INC]NAME)
+
+  AC_CACHE_CHECK([for lib[]$1], [ac_cv_lib[]Name], [
+    ac_save_LIBS="$LIBS"
+    dnl If $LIB[]NAME contains some -l options, add it to the end of LIBS,
+    dnl because these -l options might require -L options that are present in
+    dnl LIBS. -l options benefit only from the -L options listed before it.
+    dnl Otherwise, add it to the front of LIBS, because it may be a static
+    dnl library that depends on another static library that is present in LIBS.
+    dnl Static libraries benefit only from the static libraries listed after
+    dnl it.
+    case " $LIB[]NAME" in
+      *" -l"*) LIBS="$LIBS $LIB[]NAME" ;;
+      *)       LIBS="$LIB[]NAME $LIBS" ;;
+    esac
+    AC_LINK_IFELSE(
+      [AC_LANG_PROGRAM([[$3]], [[$4]])],
+      [ac_cv_lib[]Name=yes],
+      [ac_cv_lib[]Name='m4_if([$5], [], [no], [[$5]])'])
+    LIBS="$ac_save_LIBS"
+  ])
+  if test "$ac_cv_lib[]Name" = yes; then
+    HAVE_LIB[]NAME=yes
+    AC_DEFINE([HAVE_LIB]NAME, 1, [Define if you have the lib][$1 library.])
+    AC_MSG_CHECKING([how to link with lib[]$1])
+    AC_MSG_RESULT([$LIB[]NAME])
+  else
+    HAVE_LIB[]NAME=no
+    dnl If $LIB[]NAME didn't lead to a usable library, we don't need
+    dnl $INC[]NAME either.
+    CPPFLAGS="$ac_save_CPPFLAGS"
+    LIB[]NAME=
+    LTLIB[]NAME=
+    LIB[]NAME[]_PREFIX=
+  fi
+  AC_SUBST([HAVE_LIB]NAME)
+  AC_SUBST([LIB]NAME)
+  AC_SUBST([LTLIB]NAME)
+  AC_SUBST([LIB]NAME[_PREFIX])
+  popdef([NAME])
+  popdef([Name])
+])
+
+dnl Determine the platform dependent parameters needed to use rpath:
+dnl   acl_libext,
+dnl   acl_shlibext,
+dnl   acl_libname_spec,
+dnl   acl_library_names_spec,
+dnl   acl_hardcode_libdir_flag_spec,
+dnl   acl_hardcode_libdir_separator,
+dnl   acl_hardcode_direct,
+dnl   acl_hardcode_minus_L.
+AC_DEFUN([AC_LIB_RPATH],
+[
+  dnl Complain if config.rpath is missing.
+  AC_REQUIRE_AUX_FILE([config.rpath])
+  AC_REQUIRE([AC_PROG_CC])                dnl we use $CC, $GCC, $LDFLAGS
+  AC_REQUIRE([AC_LIB_PROG_LD])            dnl we use $LD, $with_gnu_ld
+  AC_REQUIRE([AC_CANONICAL_HOST])         dnl we use $host
+  AC_REQUIRE([AC_CONFIG_AUX_DIR_DEFAULT]) dnl we use $ac_aux_dir
+  AC_CACHE_CHECK([for shared library run path origin], [acl_cv_rpath], [
+    CC="$CC" GCC="$GCC" LDFLAGS="$LDFLAGS" LD="$LD" with_gnu_ld="$with_gnu_ld" \
+    ${CONFIG_SHELL-/bin/sh} "$ac_aux_dir/config.rpath" "$host" > conftest.sh
+    . ./conftest.sh
+    rm -f ./conftest.sh
+    acl_cv_rpath=done
+  ])
+  wl="$acl_cv_wl"
+  acl_libext="$acl_cv_libext"
+  acl_shlibext="$acl_cv_shlibext"
+  acl_libname_spec="$acl_cv_libname_spec"
+  acl_library_names_spec="$acl_cv_library_names_spec"
+  acl_hardcode_libdir_flag_spec="$acl_cv_hardcode_libdir_flag_spec"
+  acl_hardcode_libdir_separator="$acl_cv_hardcode_libdir_separator"
+  acl_hardcode_direct="$acl_cv_hardcode_direct"
+  acl_hardcode_minus_L="$acl_cv_hardcode_minus_L"
+  dnl Determine whether the user wants rpath handling at all.
+  AC_ARG_ENABLE([rpath],
+    [  --disable-rpath         do not hardcode runtime library paths],
+    :, enable_rpath=yes)
+])
+
+dnl AC_LIB_FROMPACKAGE(name, package)
+dnl declares that libname comes from the given package. The configure file
+dnl will then not have a --with-libname-prefix option but a
+dnl --with-package-prefix option. Several libraries can come from the same
+dnl package. This declaration must occur before an AC_LIB_LINKFLAGS or similar
+dnl macro call that searches for libname.
+AC_DEFUN([AC_LIB_FROMPACKAGE],
+[
+  pushdef([NAME],[m4_translit([$1],[abcdefghijklmnopqrstuvwxyz./+-],
+                                   [ABCDEFGHIJKLMNOPQRSTUVWXYZ____])])
+  define([acl_frompackage_]NAME, [$2])
+  popdef([NAME])
+  pushdef([PACK],[$2])
+  pushdef([PACKUP],[m4_translit(PACK,[abcdefghijklmnopqrstuvwxyz./+-],
+                                     [ABCDEFGHIJKLMNOPQRSTUVWXYZ____])])
+  define([acl_libsinpackage_]PACKUP,
+    m4_ifdef([acl_libsinpackage_]PACKUP, [m4_defn([acl_libsinpackage_]PACKUP)[, ]],)[lib$1])
+  popdef([PACKUP])
+  popdef([PACK])
+])
+
+dnl AC_LIB_LINKFLAGS_BODY(name [, dependencies]) searches for libname and
+dnl the libraries corresponding to explicit and implicit dependencies.
+dnl Sets the LIB${NAME}, LTLIB${NAME} and INC${NAME} variables.
+dnl Also, sets the LIB${NAME}_PREFIX variable to nonempty if libname was found
+dnl in ${LIB${NAME}_PREFIX}/$acl_libdirstem.
+AC_DEFUN([AC_LIB_LINKFLAGS_BODY],
+[
+  AC_REQUIRE([AC_LIB_PREPARE_MULTILIB])
+  pushdef([NAME],[m4_translit([$1],[abcdefghijklmnopqrstuvwxyz./+-],
+                                   [ABCDEFGHIJKLMNOPQRSTUVWXYZ____])])
+  pushdef([PACK],[m4_ifdef([acl_frompackage_]NAME, [acl_frompackage_]NAME, lib[$1])])
+  pushdef([PACKUP],[m4_translit(PACK,[abcdefghijklmnopqrstuvwxyz./+-],
+                                     [ABCDEFGHIJKLMNOPQRSTUVWXYZ____])])
+  pushdef([PACKLIBS],[m4_ifdef([acl_frompackage_]NAME, [acl_libsinpackage_]PACKUP, lib[$1])])
+  dnl By default, look in $includedir and $libdir.
+  use_additional=yes
+  AC_LIB_WITH_FINAL_PREFIX([
+    eval additional_includedir=\"$includedir\"
+    eval additional_libdir=\"$libdir\"
+    eval additional_libdir2=\"$exec_prefix/$acl_libdirstem2\"
+    eval additional_libdir3=\"$exec_prefix/$acl_libdirstem3\"
+  ])
+  AC_ARG_WITH(PACK[-prefix],
+[[  --with-]]PACK[[-prefix[=DIR]  search for ]PACKLIBS[ in DIR/include and DIR/lib
+  --without-]]PACK[[-prefix     don't search for ]PACKLIBS[ in includedir and libdir]],
+[
+    if test "X$withval" = "Xno"; then
+      use_additional=no
+    else
+      if test "X$withval" = "X"; then
+        AC_LIB_WITH_FINAL_PREFIX([
+          eval additional_includedir=\"$includedir\"
+          eval additional_libdir=\"$libdir\"
+          eval additional_libdir2=\"$exec_prefix/$acl_libdirstem2\"
+          eval additional_libdir3=\"$exec_prefix/$acl_libdirstem3\"
+        ])
+      else
+        additional_includedir="$withval/include"
+        additional_libdir="$withval/$acl_libdirstem"
+        additional_libdir2="$withval/$acl_libdirstem2"
+        additional_libdir3="$withval/$acl_libdirstem3"
+      fi
+    fi
+])
+  if test "X$additional_libdir2" = "X$additional_libdir"; then
+    additional_libdir2=
+  fi
+  if test "X$additional_libdir3" = "X$additional_libdir"; then
+    additional_libdir3=
+  fi
+  dnl Search the library and its dependencies in $additional_libdir and
+  dnl $LDFLAGS. Using breadth-first-seach.
+  LIB[]NAME=
+  LTLIB[]NAME=
+  INC[]NAME=
+  LIB[]NAME[]_PREFIX=
+  dnl HAVE_LIB${NAME} is an indicator that LIB${NAME}, LTLIB${NAME} have been
+  dnl computed. So it has to be reset here.
+  HAVE_LIB[]NAME=
+  rpathdirs=
+  ltrpathdirs=
+  names_already_handled=
+  names_next_round='$1 $2'
+  while test -n "$names_next_round"; do
+    names_this_round="$names_next_round"
+    names_next_round=
+    for name in $names_this_round; do
+      already_handled=
+      for n in $names_already_handled; do
+        if test "$n" = "$name"; then
+          already_handled=yes
+          break
+        fi
+      done
+      if test -z "$already_handled"; then
+        names_already_handled="$names_already_handled $name"
+        dnl See if it was already located by an earlier AC_LIB_LINKFLAGS
+        dnl or AC_LIB_HAVE_LINKFLAGS call.
+        uppername=`echo "$name" | sed -e 'y|abcdefghijklmnopqrstuvwxyz./+-|ABCDEFGHIJKLMNOPQRSTUVWXYZ____|'`
+        eval value=\"\$HAVE_LIB$uppername\"
+        if test -n "$value"; then
+          if test "$value" = yes; then
+            eval value=\"\$LIB$uppername\"
+            test -z "$value" || LIB[]NAME="${LIB[]NAME}${LIB[]NAME:+ }$value"
+            eval value=\"\$LTLIB$uppername\"
+            test -z "$value" || LTLIB[]NAME="${LTLIB[]NAME}${LTLIB[]NAME:+ }$value"
+          else
+            dnl An earlier call to AC_LIB_HAVE_LINKFLAGS has determined
+            dnl that this library doesn't exist. So just drop it.
+            :
+          fi
+        else
+          dnl Search the library lib$name in $additional_libdir and $LDFLAGS
+          dnl and the already constructed $LIBNAME/$LTLIBNAME.
+          found_dir=
+          found_la=
+          found_so=
+          found_a=
+          eval libname=\"$acl_libname_spec\"    # typically: libname=lib$name
+          if test -n "$acl_shlibext"; then
+            shrext=".$acl_shlibext"             # typically: shrext=.so
+          else
+            shrext=
+          fi
+          if test $use_additional = yes; then
+            for additional_libdir_variable in additional_libdir additional_libdir2 additional_libdir3; do
+              if test "X$found_dir" = "X"; then
+                eval dir=\$$additional_libdir_variable
+                if test -n "$dir"; then
+                  dnl The same code as in the loop below:
+                  dnl First look for a shared library.
+                  if test -n "$acl_shlibext"; then
+                    if test -f "$dir/$libname$shrext" && acl_is_expected_elfclass < "$dir/$libname$shrext"; then
+                      found_dir="$dir"
+                      found_so="$dir/$libname$shrext"
+                    else
+                      if test "$acl_library_names_spec" = '$libname$shrext$versuffix'; then
+                        ver=`(cd "$dir" && \
+                              for f in "$libname$shrext".*; do echo "$f"; done \
+                              | sed -e "s,^$libname$shrext\\\\.,," \
+                              | sort -t '.' -n -r -k1,1 -k2,2 -k3,3 -k4,4 -k5,5 \
+                              | sed 1q ) 2>/dev/null`
+                        if test -n "$ver" && test -f "$dir/$libname$shrext.$ver" && acl_is_expected_elfclass < "$dir/$libname$shrext.$ver"; then
+                          found_dir="$dir"
+                          found_so="$dir/$libname$shrext.$ver"
+                        fi
+                      else
+                        eval library_names=\"$acl_library_names_spec\"
+                        for f in $library_names; do
+                          if test -f "$dir/$f" && acl_is_expected_elfclass < "$dir/$f"; then
+                            found_dir="$dir"
+                            found_so="$dir/$f"
+                            break
+                          fi
+                        done
+                      fi
+                    fi
+                  fi
+                  dnl Then look for a static library.
+                  if test "X$found_dir" = "X"; then
+                    if test -f "$dir/$libname.$acl_libext" && ${AR-ar} -p "$dir/$libname.$acl_libext" | acl_is_expected_elfclass; then
+                      found_dir="$dir"
+                      found_a="$dir/$libname.$acl_libext"
+                    fi
+                  fi
+                  if test "X$found_dir" != "X"; then
+                    if test -f "$dir/$libname.la"; then
+                      found_la="$dir/$libname.la"
+                    fi
+                  fi
+                fi
+              fi
+            done
+          fi
+          if test "X$found_dir" = "X"; then
+            for x in $LDFLAGS $LTLIB[]NAME; do
+              AC_LIB_WITH_FINAL_PREFIX([eval x=\"$x\"])
+              case "$x" in
+                -L*)
+                  dir=`echo "X$x" | sed -e 's/^X-L//'`
+                  dnl First look for a shared library.
+                  if test -n "$acl_shlibext"; then
+                    if test -f "$dir/$libname$shrext" && acl_is_expected_elfclass < "$dir/$libname$shrext"; then
+                      found_dir="$dir"
+                      found_so="$dir/$libname$shrext"
+                    else
+                      if test "$acl_library_names_spec" = '$libname$shrext$versuffix'; then
+                        ver=`(cd "$dir" && \
+                              for f in "$libname$shrext".*; do echo "$f"; done \
+                              | sed -e "s,^$libname$shrext\\\\.,," \
+                              | sort -t '.' -n -r -k1,1 -k2,2 -k3,3 -k4,4 -k5,5 \
+                              | sed 1q ) 2>/dev/null`
+                        if test -n "$ver" && test -f "$dir/$libname$shrext.$ver" && acl_is_expected_elfclass < "$dir/$libname$shrext.$ver"; then
+                          found_dir="$dir"
+                          found_so="$dir/$libname$shrext.$ver"
+                        fi
+                      else
+                        eval library_names=\"$acl_library_names_spec\"
+                        for f in $library_names; do
+                          if test -f "$dir/$f" && acl_is_expected_elfclass < "$dir/$f"; then
+                            found_dir="$dir"
+                            found_so="$dir/$f"
+                            break
+                          fi
+                        done
+                      fi
+                    fi
+                  fi
+                  dnl Then look for a static library.
+                  if test "X$found_dir" = "X"; then
+                    if test -f "$dir/$libname.$acl_libext" && ${AR-ar} -p "$dir/$libname.$acl_libext" | acl_is_expected_elfclass; then
+                      found_dir="$dir"
+                      found_a="$dir/$libname.$acl_libext"
+                    fi
+                  fi
+                  if test "X$found_dir" != "X"; then
+                    if test -f "$dir/$libname.la"; then
+                      found_la="$dir/$libname.la"
+                    fi
+                  fi
+                  ;;
+              esac
+              if test "X$found_dir" != "X"; then
+                break
+              fi
+            done
+          fi
+          if test "X$found_dir" != "X"; then
+            dnl Found the library.
+            LTLIB[]NAME="${LTLIB[]NAME}${LTLIB[]NAME:+ }-L$found_dir -l$name"
+            if test "X$found_so" != "X"; then
+              dnl Linking with a shared library. We attempt to hardcode its
+              dnl directory into the executable's runpath, unless it's the
+              dnl standard /usr/lib.
+              if test "$enable_rpath" = no \
+                 || test "X$found_dir" = "X/usr/$acl_libdirstem" \
+                 || test "X$found_dir" = "X/usr/$acl_libdirstem2" \
+                 || test "X$found_dir" = "X/usr/$acl_libdirstem3"; then
+                dnl No hardcoding is needed.
+                LIB[]NAME="${LIB[]NAME}${LIB[]NAME:+ }$found_so"
+              else
+                dnl Use an explicit option to hardcode DIR into the resulting
+                dnl binary.
+                dnl Potentially add DIR to ltrpathdirs.
+                dnl The ltrpathdirs will be appended to $LTLIBNAME at the end.
+                haveit=
+                for x in $ltrpathdirs; do
+                  if test "X$x" = "X$found_dir"; then
+                    haveit=yes
+                    break
+                  fi
+                done
+                if test -z "$haveit"; then
+                  ltrpathdirs="$ltrpathdirs $found_dir"
+                fi
+                dnl The hardcoding into $LIBNAME is system dependent.
+                if test "$acl_hardcode_direct" = yes; then
+                  dnl Using DIR/libNAME.so during linking hardcodes DIR into the
+                  dnl resulting binary.
+                  LIB[]NAME="${LIB[]NAME}${LIB[]NAME:+ }$found_so"
+                else
+                  if test -n "$acl_hardcode_libdir_flag_spec" && test "$acl_hardcode_minus_L" = no; then
+                    dnl Use an explicit option to hardcode DIR into the resulting
+                    dnl binary.
+                    LIB[]NAME="${LIB[]NAME}${LIB[]NAME:+ }$found_so"
+                    dnl Potentially add DIR to rpathdirs.
+                    dnl The rpathdirs will be appended to $LIBNAME at the end.
+                    haveit=
+                    for x in $rpathdirs; do
+                      if test "X$x" = "X$found_dir"; then
+                        haveit=yes
+                        break
+                      fi
+                    done
+                    if test -z "$haveit"; then
+                      rpathdirs="$rpathdirs $found_dir"
+                    fi
+                  else
+                    dnl Rely on "-L$found_dir".
+                    dnl But don't add it if it's already contained in the LDFLAGS
+                    dnl or the already constructed $LIBNAME
+                    haveit=
+                    for x in $LDFLAGS $LIB[]NAME; do
+                      AC_LIB_WITH_FINAL_PREFIX([eval x=\"$x\"])
+                      if test "X$x" = "X-L$found_dir"; then
+                        haveit=yes
+                        break
+                      fi
+                    done
+                    if test -z "$haveit"; then
+                      LIB[]NAME="${LIB[]NAME}${LIB[]NAME:+ }-L$found_dir"
+                    fi
+                    if test "$acl_hardcode_minus_L" != no; then
+                      dnl FIXME: Not sure whether we should use
+                      dnl "-L$found_dir -l$name" or "-L$found_dir $found_so"
+                      dnl here.
+                      LIB[]NAME="${LIB[]NAME}${LIB[]NAME:+ }$found_so"
+                    else
+                      dnl We cannot use $acl_hardcode_runpath_var and LD_RUN_PATH
+                      dnl here, because this doesn't fit in flags passed to the
+                      dnl compiler. So give up. No hardcoding. This affects only
+                      dnl very old systems.
+                      dnl FIXME: Not sure whether we should use
+                      dnl "-L$found_dir -l$name" or "-L$found_dir $found_so"
+                      dnl here.
+                      LIB[]NAME="${LIB[]NAME}${LIB[]NAME:+ }-l$name"
+                    fi
+                  fi
+                fi
+              fi
+            else
+              if test "X$found_a" != "X"; then
+                dnl Linking with a static library.
+                LIB[]NAME="${LIB[]NAME}${LIB[]NAME:+ }$found_a"
+              else
+                dnl We shouldn't come here, but anyway it's good to have a
+                dnl fallback.
+                LIB[]NAME="${LIB[]NAME}${LIB[]NAME:+ }-L$found_dir -l$name"
+              fi
+            fi
+            dnl Assume the include files are nearby.
+            additional_includedir=
+            case "$found_dir" in
+              */$acl_libdirstem | */$acl_libdirstem/)
+                basedir=`echo "X$found_dir" | sed -e 's,^X,,' -e "s,/$acl_libdirstem/"'*$,,'`
+                if test "$name" = '$1'; then
+                  LIB[]NAME[]_PREFIX="$basedir"
+                fi
+                additional_includedir="$basedir/include"
+                ;;
+              */$acl_libdirstem2 | */$acl_libdirstem2/)
+                basedir=`echo "X$found_dir" | sed -e 's,^X,,' -e "s,/$acl_libdirstem2/"'*$,,'`
+                if test "$name" = '$1'; then
+                  LIB[]NAME[]_PREFIX="$basedir"
+                fi
+                additional_includedir="$basedir/include"
+                ;;
+              */$acl_libdirstem3 | */$acl_libdirstem3/)
+                basedir=`echo "X$found_dir" | sed -e 's,^X,,' -e "s,/$acl_libdirstem3/"'*$,,'`
+                if test "$name" = '$1'; then
+                  LIB[]NAME[]_PREFIX="$basedir"
+                fi
+                additional_includedir="$basedir/include"
+                ;;
+            esac
+            if test "X$additional_includedir" != "X"; then
+              dnl Potentially add $additional_includedir to $INCNAME.
+              dnl But don't add it
+              dnl   1. if it's the standard /usr/include,
+              dnl   2. if it's /usr/local/include and we are using GCC on Linux,
+              dnl   3. if it's already present in $CPPFLAGS or the already
+              dnl      constructed $INCNAME,
+              dnl   4. if it doesn't exist as a directory.
+              if test "X$additional_includedir" != "X/usr/include"; then
+                haveit=
+                if test "X$additional_includedir" = "X/usr/local/include"; then
+                  if test -n "$GCC"; then
+                    case $host_os in
+                      linux* | gnu* | k*bsd*-gnu) haveit=yes;;
+                    esac
+                  fi
+                fi
+                if test -z "$haveit"; then
+                  for x in $CPPFLAGS $INC[]NAME; do
+                    AC_LIB_WITH_FINAL_PREFIX([eval x=\"$x\"])
+                    if test "X$x" = "X-I$additional_includedir"; then
+                      haveit=yes
+                      break
+                    fi
+                  done
+                  if test -z "$haveit"; then
+                    if test -d "$additional_includedir"; then
+                      dnl Really add $additional_includedir to $INCNAME.
+                      INC[]NAME="${INC[]NAME}${INC[]NAME:+ }-I$additional_includedir"
+                    fi
+                  fi
+                fi
+              fi
+            fi
+            dnl Look for dependencies.
+            if test -n "$found_la"; then
+              dnl Read the .la file. It defines the variables
+              dnl dlname, library_names, old_library, dependency_libs, current,
+              dnl age, revision, installed, dlopen, dlpreopen, libdir.
+              save_libdir="$libdir"
+              case "$found_la" in
+                */* | *\\*) . "$found_la" ;;
+                *) . "./$found_la" ;;
+              esac
+              libdir="$save_libdir"
+              dnl We use only dependency_libs.
+              for dep in $dependency_libs; do
+                case "$dep" in
+                  -L*)
+                    dependency_libdir=`echo "X$dep" | sed -e 's/^X-L//'`
+                    dnl Potentially add $dependency_libdir to $LIBNAME and $LTLIBNAME.
+                    dnl But don't add it
+                    dnl   1. if it's the standard /usr/lib,
+                    dnl   2. if it's /usr/local/lib and we are using GCC on Linux,
+                    dnl   3. if it's already present in $LDFLAGS or the already
+                    dnl      constructed $LIBNAME,
+                    dnl   4. if it doesn't exist as a directory.
+                    if test "X$dependency_libdir" != "X/usr/$acl_libdirstem" \
+                       && test "X$dependency_libdir" != "X/usr/$acl_libdirstem2" \
+                       && test "X$dependency_libdir" != "X/usr/$acl_libdirstem3"; then
+                      haveit=
+                      if test "X$dependency_libdir" = "X/usr/local/$acl_libdirstem" \
+                         || test "X$dependency_libdir" = "X/usr/local/$acl_libdirstem2" \
+                         || test "X$dependency_libdir" = "X/usr/local/$acl_libdirstem3"; then
+                        if test -n "$GCC"; then
+                          case $host_os in
+                            linux* | gnu* | k*bsd*-gnu) haveit=yes;;
+                          esac
+                        fi
+                      fi
+                      if test -z "$haveit"; then
+                        haveit=
+                        for x in $LDFLAGS $LIB[]NAME; do
+                          AC_LIB_WITH_FINAL_PREFIX([eval x=\"$x\"])
+                          if test "X$x" = "X-L$dependency_libdir"; then
+                            haveit=yes
+                            break
+                          fi
+                        done
+                        if test -z "$haveit"; then
+                          if test -d "$dependency_libdir"; then
+                            dnl Really add $dependency_libdir to $LIBNAME.
+                            LIB[]NAME="${LIB[]NAME}${LIB[]NAME:+ }-L$dependency_libdir"
+                          fi
+                        fi
+                        haveit=
+                        for x in $LDFLAGS $LTLIB[]NAME; do
+                          AC_LIB_WITH_FINAL_PREFIX([eval x=\"$x\"])
+                          if test "X$x" = "X-L$dependency_libdir"; then
+                            haveit=yes
+                            break
+                          fi
+                        done
+                        if test -z "$haveit"; then
+                          if test -d "$dependency_libdir"; then
+                            dnl Really add $dependency_libdir to $LTLIBNAME.
+                            LTLIB[]NAME="${LTLIB[]NAME}${LTLIB[]NAME:+ }-L$dependency_libdir"
+                          fi
+                        fi
+                      fi
+                    fi
+                    ;;
+                  -R*)
+                    dir=`echo "X$dep" | sed -e 's/^X-R//'`
+                    if test "$enable_rpath" != no; then
+                      dnl Potentially add DIR to rpathdirs.
+                      dnl The rpathdirs will be appended to $LIBNAME at the end.
+                      haveit=
+                      for x in $rpathdirs; do
+                        if test "X$x" = "X$dir"; then
+                          haveit=yes
+                          break
+                        fi
+                      done
+                      if test -z "$haveit"; then
+                        rpathdirs="$rpathdirs $dir"
+                      fi
+                      dnl Potentially add DIR to ltrpathdirs.
+                      dnl The ltrpathdirs will be appended to $LTLIBNAME at the end.
+                      haveit=
+                      for x in $ltrpathdirs; do
+                        if test "X$x" = "X$dir"; then
+                          haveit=yes
+                          break
+                        fi
+                      done
+                      if test -z "$haveit"; then
+                        ltrpathdirs="$ltrpathdirs $dir"
+                      fi
+                    fi
+                    ;;
+                  -l*)
+                    dnl Handle this in the next round.
+                    dnl But on GNU systems, ignore -lc options, because
+                    dnl   - linking with libc is the default anyway,
+                    dnl   - linking with libc.a may produce an error
+                    dnl     "/usr/bin/ld: dynamic STT_GNU_IFUNC symbol `strcmp' with pointer equality in `/usr/lib/libc.a(strcmp.o)' can not be used when making an executable; recompile with -fPIE and relink with -pie"
+                    dnl     or may produce an executable that always crashes, see
+                    dnl     <https://lists.gnu.org/archive/html/grep-devel/2020-09/msg00052.html>.
+                    dep=`echo "X$dep" | sed -e 's/^X-l//'`
+                    if test "X$dep" != Xc \
+                       || case $host_os in
+                            linux* | gnu* | k*bsd*-gnu) false ;;
+                            *)                          true ;;
+                          esac; then
+                      names_next_round="$names_next_round $dep"
+                    fi
+                    ;;
+                  *.la)
+                    dnl Handle this in the next round. Throw away the .la's
+                    dnl directory; it is already contained in a preceding -L
+                    dnl option.
+                    names_next_round="$names_next_round "`echo "X$dep" | sed -e 's,^X.*/,,' -e 's,^lib,,' -e 's,\.la$,,'`
+                    ;;
+                  *)
+                    dnl Most likely an immediate library name.
+                    LIB[]NAME="${LIB[]NAME}${LIB[]NAME:+ }$dep"
+                    LTLIB[]NAME="${LTLIB[]NAME}${LTLIB[]NAME:+ }$dep"
+                    ;;
+                esac
+              done
+            fi
+          else
+            dnl Didn't find the library; assume it is in the system directories
+            dnl known to the linker and runtime loader. (All the system
+            dnl directories known to the linker should also be known to the
+            dnl runtime loader, otherwise the system is severely misconfigured.)
+            LIB[]NAME="${LIB[]NAME}${LIB[]NAME:+ }-l$name"
+            LTLIB[]NAME="${LTLIB[]NAME}${LTLIB[]NAME:+ }-l$name"
+          fi
+        fi
+      fi
+    done
+  done
+  if test "X$rpathdirs" != "X"; then
+    if test -n "$acl_hardcode_libdir_separator"; then
+      dnl Weird platform: only the last -rpath option counts, the user must
+      dnl pass all path elements in one option. We can arrange that for a
+      dnl single library, but not when more than one $LIBNAMEs are used.
+      alldirs=
+      for found_dir in $rpathdirs; do
+        alldirs="${alldirs}${alldirs:+$acl_hardcode_libdir_separator}$found_dir"
+      done
+      dnl Note: acl_hardcode_libdir_flag_spec uses $libdir and $wl.
+      acl_save_libdir="$libdir"
+      libdir="$alldirs"
+      eval flag=\"$acl_hardcode_libdir_flag_spec\"
+      libdir="$acl_save_libdir"
+      LIB[]NAME="${LIB[]NAME}${LIB[]NAME:+ }$flag"
+    else
+      dnl The -rpath options are cumulative.
+      for found_dir in $rpathdirs; do
+        acl_save_libdir="$libdir"
+        libdir="$found_dir"
+        eval flag=\"$acl_hardcode_libdir_flag_spec\"
+        libdir="$acl_save_libdir"
+        LIB[]NAME="${LIB[]NAME}${LIB[]NAME:+ }$flag"
+      done
+    fi
+  fi
+  if test "X$ltrpathdirs" != "X"; then
+    dnl When using libtool, the option that works for both libraries and
+    dnl executables is -R. The -R options are cumulative.
+    for found_dir in $ltrpathdirs; do
+      LTLIB[]NAME="${LTLIB[]NAME}${LTLIB[]NAME:+ }-R$found_dir"
+    done
+  fi
+  popdef([PACKLIBS])
+  popdef([PACKUP])
+  popdef([PACK])
+  popdef([NAME])
+])
+
+dnl AC_LIB_APPENDTOVAR(VAR, CONTENTS) appends the elements of CONTENTS to VAR,
+dnl unless already present in VAR.
+dnl Works only for CPPFLAGS, not for LIB* variables because that sometimes
+dnl contains two or three consecutive elements that belong together.
+AC_DEFUN([AC_LIB_APPENDTOVAR],
+[
+  for element in [$2]; do
+    haveit=
+    for x in $[$1]; do
+      AC_LIB_WITH_FINAL_PREFIX([eval x=\"$x\"])
+      if test "X$x" = "X$element"; then
+        haveit=yes
+        break
+      fi
+    done
+    if test -z "$haveit"; then
+      [$1]="${[$1]}${[$1]:+ }$element"
+    fi
+  done
+])
+
+dnl For those cases where a variable contains several -L and -l options
+dnl referring to unknown libraries and directories, this macro determines the
+dnl necessary additional linker options for the runtime path.
+dnl AC_LIB_LINKFLAGS_FROM_LIBS([LDADDVAR], [LIBSVALUE], [USE-LIBTOOL])
+dnl sets LDADDVAR to linker options needed together with LIBSVALUE.
+dnl If USE-LIBTOOL evaluates to non-empty, linking with libtool is assumed,
+dnl otherwise linking without libtool is assumed.
+AC_DEFUN([AC_LIB_LINKFLAGS_FROM_LIBS],
+[
+  AC_REQUIRE([AC_LIB_RPATH])
+  AC_REQUIRE([AC_LIB_PREPARE_MULTILIB])
+  $1=
+  if test "$enable_rpath" != no; then
+    if test -n "$acl_hardcode_libdir_flag_spec" && test "$acl_hardcode_minus_L" = no; then
+      dnl Use an explicit option to hardcode directories into the resulting
+      dnl binary.
+      rpathdirs=
+      next=
+      for opt in $2; do
+        if test -n "$next"; then
+          dir="$next"
+          dnl No need to hardcode the standard /usr/lib.
+          if test "X$dir" != "X/usr/$acl_libdirstem" \
+             && test "X$dir" != "X/usr/$acl_libdirstem2" \
+             && test "X$dir" != "X/usr/$acl_libdirstem3"; then
+            rpathdirs="$rpathdirs $dir"
+          fi
+          next=
+        else
+          case $opt in
+            -L) next=yes ;;
+            -L*) dir=`echo "X$opt" | sed -e 's,^X-L,,'`
+                 dnl No need to hardcode the standard /usr/lib.
+                 if test "X$dir" != "X/usr/$acl_libdirstem" \
+                    && test "X$dir" != "X/usr/$acl_libdirstem2" \
+                    && test "X$dir" != "X/usr/$acl_libdirstem3"; then
+                   rpathdirs="$rpathdirs $dir"
+                 fi
+                 next= ;;
+            *) next= ;;
+          esac
+        fi
+      done
+      if test "X$rpathdirs" != "X"; then
+        if test -n ""$3""; then
+          dnl libtool is used for linking. Use -R options.
+          for dir in $rpathdirs; do
+            $1="${$1}${$1:+ }-R$dir"
+          done
+        else
+          dnl The linker is used for linking directly.
+          if test -n "$acl_hardcode_libdir_separator"; then
+            dnl Weird platform: only the last -rpath option counts, the user
+            dnl must pass all path elements in one option.
+            alldirs=
+            for dir in $rpathdirs; do
+              alldirs="${alldirs}${alldirs:+$acl_hardcode_libdir_separator}$dir"
+            done
+            acl_save_libdir="$libdir"
+            libdir="$alldirs"
+            eval flag=\"$acl_hardcode_libdir_flag_spec\"
+            libdir="$acl_save_libdir"
+            $1="$flag"
+          else
+            dnl The -rpath options are cumulative.
+            for dir in $rpathdirs; do
+              acl_save_libdir="$libdir"
+              libdir="$dir"
+              eval flag=\"$acl_hardcode_libdir_flag_spec\"
+              libdir="$acl_save_libdir"
+              $1="${$1}${$1:+ }$flag"
+            done
+          fi
+        fi
+      fi
+    fi
+  fi
+  AC_SUBST([$1])
+])
diff --git a/m4/lib-prefix.m4 b/m4/lib-prefix.m4
new file mode 100644
index 0000000..2bcdfdf
--- /dev/null
+++ b/m4/lib-prefix.m4
@@ -0,0 +1,323 @@
+# lib-prefix.m4 serial 19
+dnl Copyright (C) 2001-2005, 2008-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl From Bruno Haible.
+
+dnl AC_LIB_PREFIX adds to the CPPFLAGS and LDFLAGS the flags that are needed
+dnl to access previously installed libraries. The basic assumption is that
+dnl a user will want packages to use other packages he previously installed
+dnl with the same --prefix option.
+dnl This macro is not needed if only AC_LIB_LINKFLAGS is used to locate
+dnl libraries, but is otherwise very convenient.
+AC_DEFUN([AC_LIB_PREFIX],
+[
+  AC_BEFORE([$0], [AC_LIB_LINKFLAGS])
+  AC_REQUIRE([AC_PROG_CC])
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  AC_REQUIRE([AC_LIB_PREPARE_MULTILIB])
+  AC_REQUIRE([AC_LIB_PREPARE_PREFIX])
+  dnl By default, look in $includedir and $libdir.
+  use_additional=yes
+  AC_LIB_WITH_FINAL_PREFIX([
+    eval additional_includedir=\"$includedir\"
+    eval additional_libdir=\"$libdir\"
+  ])
+  AC_ARG_WITH([lib-prefix],
+[[  --with-lib-prefix[=DIR] search for libraries in DIR/include and DIR/lib
+  --without-lib-prefix    don't search for libraries in includedir and libdir]],
+[
+    if test "X$withval" = "Xno"; then
+      use_additional=no
+    else
+      if test "X$withval" = "X"; then
+        AC_LIB_WITH_FINAL_PREFIX([
+          eval additional_includedir=\"$includedir\"
+          eval additional_libdir=\"$libdir\"
+        ])
+      else
+        additional_includedir="$withval/include"
+        additional_libdir="$withval/$acl_libdirstem"
+      fi
+    fi
+])
+  if test $use_additional = yes; then
+    dnl Potentially add $additional_includedir to $CPPFLAGS.
+    dnl But don't add it
+    dnl   1. if it's the standard /usr/include,
+    dnl   2. if it's already present in $CPPFLAGS,
+    dnl   3. if it's /usr/local/include and we are using GCC on Linux,
+    dnl   4. if it doesn't exist as a directory.
+    if test "X$additional_includedir" != "X/usr/include"; then
+      haveit=
+      for x in $CPPFLAGS; do
+        AC_LIB_WITH_FINAL_PREFIX([eval x=\"$x\"])
+        if test "X$x" = "X-I$additional_includedir"; then
+          haveit=yes
+          break
+        fi
+      done
+      if test -z "$haveit"; then
+        if test "X$additional_includedir" = "X/usr/local/include"; then
+          if test -n "$GCC"; then
+            case $host_os in
+              linux* | gnu* | k*bsd*-gnu) haveit=yes;;
+            esac
+          fi
+        fi
+        if test -z "$haveit"; then
+          if test -d "$additional_includedir"; then
+            dnl Really add $additional_includedir to $CPPFLAGS.
+            CPPFLAGS="${CPPFLAGS}${CPPFLAGS:+ }-I$additional_includedir"
+          fi
+        fi
+      fi
+    fi
+    dnl Potentially add $additional_libdir to $LDFLAGS.
+    dnl But don't add it
+    dnl   1. if it's the standard /usr/lib,
+    dnl   2. if it's already present in $LDFLAGS,
+    dnl   3. if it's /usr/local/lib and we are using GCC on Linux,
+    dnl   4. if it doesn't exist as a directory.
+    if test "X$additional_libdir" != "X/usr/$acl_libdirstem"; then
+      haveit=
+      for x in $LDFLAGS; do
+        AC_LIB_WITH_FINAL_PREFIX([eval x=\"$x\"])
+        if test "X$x" = "X-L$additional_libdir"; then
+          haveit=yes
+          break
+        fi
+      done
+      if test -z "$haveit"; then
+        if test "X$additional_libdir" = "X/usr/local/$acl_libdirstem"; then
+          if test -n "$GCC"; then
+            case $host_os in
+              linux*) haveit=yes;;
+            esac
+          fi
+        fi
+        if test -z "$haveit"; then
+          if test -d "$additional_libdir"; then
+            dnl Really add $additional_libdir to $LDFLAGS.
+            LDFLAGS="${LDFLAGS}${LDFLAGS:+ }-L$additional_libdir"
+          fi
+        fi
+      fi
+    fi
+  fi
+])
+
+dnl AC_LIB_PREPARE_PREFIX creates variables acl_final_prefix,
+dnl acl_final_exec_prefix, containing the values to which $prefix and
+dnl $exec_prefix will expand at the end of the configure script.
+AC_DEFUN([AC_LIB_PREPARE_PREFIX],
+[
+  dnl Unfortunately, prefix and exec_prefix get only finally determined
+  dnl at the end of configure.
+  if test "X$prefix" = "XNONE"; then
+    acl_final_prefix="$ac_default_prefix"
+  else
+    acl_final_prefix="$prefix"
+  fi
+  if test "X$exec_prefix" = "XNONE"; then
+    acl_final_exec_prefix='${prefix}'
+  else
+    acl_final_exec_prefix="$exec_prefix"
+  fi
+  acl_save_prefix="$prefix"
+  prefix="$acl_final_prefix"
+  eval acl_final_exec_prefix=\"$acl_final_exec_prefix\"
+  prefix="$acl_save_prefix"
+])
+
+dnl AC_LIB_WITH_FINAL_PREFIX([statement]) evaluates statement, with the
+dnl variables prefix and exec_prefix bound to the values they will have
+dnl at the end of the configure script.
+AC_DEFUN([AC_LIB_WITH_FINAL_PREFIX],
+[
+  acl_save_prefix="$prefix"
+  prefix="$acl_final_prefix"
+  acl_save_exec_prefix="$exec_prefix"
+  exec_prefix="$acl_final_exec_prefix"
+  $1
+  exec_prefix="$acl_save_exec_prefix"
+  prefix="$acl_save_prefix"
+])
+
+dnl AC_LIB_PREPARE_MULTILIB creates
+dnl - a function acl_is_expected_elfclass, that tests whether standard input
+dn;   has a 32-bit or 64-bit ELF header, depending on the host CPU ABI,
+dnl - 3 variables acl_libdirstem, acl_libdirstem2, acl_libdirstem3, containing
+dnl   the basename of the libdir to try in turn, either "lib" or "lib64" or
+dnl   "lib/64" or "lib32" or "lib/sparcv9" or "lib/amd64" or similar.
+AC_DEFUN([AC_LIB_PREPARE_MULTILIB],
+[
+  dnl There is no formal standard regarding lib, lib32, and lib64.
+  dnl On most glibc systems, the current practice is that on a system supporting
+  dnl 32-bit and 64-bit instruction sets or ABIs, 64-bit libraries go under
+  dnl $prefix/lib64 and 32-bit libraries go under $prefix/lib. However, on
+  dnl Arch Linux based distributions, it's the opposite: 32-bit libraries go
+  dnl under $prefix/lib32 and 64-bit libraries go under $prefix/lib.
+  dnl We determine the compiler's default mode by looking at the compiler's
+  dnl library search path. If at least one of its elements ends in /lib64 or
+  dnl points to a directory whose absolute pathname ends in /lib64, we use that
+  dnl for 64-bit ABIs. Similarly for 32-bit ABIs. Otherwise we use the default,
+  dnl namely "lib".
+  dnl On Solaris systems, the current practice is that on a system supporting
+  dnl 32-bit and 64-bit instruction sets or ABIs, 64-bit libraries go under
+  dnl $prefix/lib/64 (which is a symlink to either $prefix/lib/sparcv9 or
+  dnl $prefix/lib/amd64) and 32-bit libraries go under $prefix/lib.
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  AC_REQUIRE([gl_HOST_CPU_C_ABI_32BIT])
+
+  AC_CACHE_CHECK([for ELF binary format], [gl_cv_elf],
+    [AC_EGREP_CPP([Extensible Linking Format],
+       [#ifdef __ELF__
+        Extensible Linking Format
+        #endif
+       ],
+       [gl_cv_elf=yes],
+       [gl_cv_elf=no])
+    ])
+  if test $gl_cv_elf = yes; then
+    # Extract the ELF class of a file (5th byte) in decimal.
+    # Cf. https://en.wikipedia.org/wiki/Executable_and_Linkable_Format#File_header
+    if od -A x < /dev/null >/dev/null 2>/dev/null; then
+      # Use POSIX od.
+      func_elfclass ()
+      {
+        od -A n -t d1 -j 4 -N 1
+      }
+    else
+      # Use BSD hexdump.
+      func_elfclass ()
+      {
+        dd bs=1 count=1 skip=4 2>/dev/null | hexdump -e '1/1 "%3d "'
+        echo
+      }
+    fi
+    # Use 'expr', not 'test', to compare the values of func_elfclass, because on
+    # Solaris 11 OpenIndiana and Solaris 11 OmniOS, the result is 001 or 002,
+    # not 1 or 2.
+changequote(,)dnl
+    case $HOST_CPU_C_ABI_32BIT in
+      yes)
+        # 32-bit ABI.
+        acl_is_expected_elfclass ()
+        {
+          expr "`func_elfclass | sed -e 's/[ 	]//g'`" = 1 > /dev/null
+        }
+        ;;
+      no)
+        # 64-bit ABI.
+        acl_is_expected_elfclass ()
+        {
+          expr "`func_elfclass | sed -e 's/[ 	]//g'`" = 2 > /dev/null
+        }
+        ;;
+      *)
+        # Unknown.
+        acl_is_expected_elfclass ()
+        {
+          :
+        }
+        ;;
+    esac
+changequote([,])dnl
+  else
+    acl_is_expected_elfclass ()
+    {
+      :
+    }
+  fi
+
+  dnl Allow the user to override the result by setting acl_cv_libdirstems.
+  AC_CACHE_CHECK([for the common suffixes of directories in the library search path],
+    [acl_cv_libdirstems],
+    [dnl Try 'lib' first, because that's the default for libdir in GNU, see
+     dnl <https://www.gnu.org/prep/standards/html_node/Directory-Variables.html>.
+     acl_libdirstem=lib
+     acl_libdirstem2=
+     acl_libdirstem3=
+     case "$host_os" in
+       solaris*)
+         dnl See Solaris 10 Software Developer Collection > Solaris 64-bit Developer's Guide > The Development Environment
+         dnl <https://docs.oracle.com/cd/E19253-01/816-5138/dev-env/index.html>.
+         dnl "Portable Makefiles should refer to any library directories using the 64 symbolic link."
+         dnl But we want to recognize the sparcv9 or amd64 subdirectory also if the
+         dnl symlink is missing, so we set acl_libdirstem2 too.
+         if test $HOST_CPU_C_ABI_32BIT = no; then
+           acl_libdirstem2=lib/64
+           case "$host_cpu" in
+             sparc*)        acl_libdirstem3=lib/sparcv9 ;;
+             i*86 | x86_64) acl_libdirstem3=lib/amd64 ;;
+           esac
+         fi
+         ;;
+       *)
+         dnl If $CC generates code for a 32-bit ABI, the libraries are
+         dnl surely under $prefix/lib or $prefix/lib32, not $prefix/lib64.
+         dnl Similarly, if $CC generates code for a 64-bit ABI, the libraries
+         dnl are surely under $prefix/lib or $prefix/lib64, not $prefix/lib32.
+         dnl Find the compiler's search path. However, non-system compilers
+         dnl sometimes have odd library search paths. But we can't simply invoke
+         dnl '/usr/bin/gcc -print-search-dirs' because that would not take into
+         dnl account the -m32/-m31 or -m64 options from the $CC or $CFLAGS.
+         searchpath=`(LC_ALL=C $CC $CPPFLAGS $CFLAGS -print-search-dirs) 2>/dev/null \
+                     | sed -n -e 's,^libraries: ,,p' | sed -e 's,^=,,'`
+         if test $HOST_CPU_C_ABI_32BIT != no; then
+           # 32-bit or unknown ABI.
+           if test -d /usr/lib32; then
+             acl_libdirstem2=lib32
+           fi
+         fi
+         if test $HOST_CPU_C_ABI_32BIT != yes; then
+           # 64-bit or unknown ABI.
+           if test -d /usr/lib64; then
+             acl_libdirstem3=lib64
+           fi
+         fi
+         if test -n "$searchpath"; then
+           acl_save_IFS="${IFS= 	}"; IFS=":"
+           for searchdir in $searchpath; do
+             if test -d "$searchdir"; then
+               case "$searchdir" in
+                 */lib32/ | */lib32 ) acl_libdirstem2=lib32 ;;
+                 */lib64/ | */lib64 ) acl_libdirstem3=lib64 ;;
+                 */../ | */.. )
+                   # Better ignore directories of this form. They are misleading.
+                   ;;
+                 *) searchdir=`cd "$searchdir" && pwd`
+                    case "$searchdir" in
+                      */lib32 ) acl_libdirstem2=lib32 ;;
+                      */lib64 ) acl_libdirstem3=lib64 ;;
+                    esac ;;
+               esac
+             fi
+           done
+           IFS="$acl_save_IFS"
+           if test $HOST_CPU_C_ABI_32BIT = yes; then
+             # 32-bit ABI.
+             acl_libdirstem3=
+           fi
+           if test $HOST_CPU_C_ABI_32BIT = no; then
+             # 64-bit ABI.
+             acl_libdirstem2=
+           fi
+         fi
+         ;;
+     esac
+     test -n "$acl_libdirstem2" || acl_libdirstem2="$acl_libdirstem"
+     test -n "$acl_libdirstem3" || acl_libdirstem3="$acl_libdirstem"
+     acl_cv_libdirstems="$acl_libdirstem,$acl_libdirstem2,$acl_libdirstem3"
+    ])
+  dnl Decompose acl_cv_libdirstems into acl_libdirstem, acl_libdirstem2, and
+  dnl acl_libdirstem3.
+changequote(,)dnl
+  acl_libdirstem=`echo "$acl_cv_libdirstems" | sed -e 's/,.*//'`
+  acl_libdirstem2=`echo "$acl_cv_libdirstems" | sed -e 's/^[^,]*,//' -e 's/,.*//'`
+  acl_libdirstem3=`echo "$acl_cv_libdirstems" | sed -e 's/^[^,]*,[^,]*,//' -e 's/,.*//'`
+changequote([,])dnl
+])
diff --git a/m4/libunistring-base.m4 b/m4/libunistring-base.m4
new file mode 100644
index 0000000..268ec5f
--- /dev/null
+++ b/m4/libunistring-base.m4
@@ -0,0 +1,141 @@
+# libunistring-base.m4 serial 5
+dnl Copyright (C) 2010-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl From Paolo Bonzini and Bruno Haible.
+
+dnl gl_LIBUNISTRING_MODULE([VERSION], [Module])
+dnl Declares that the source files of Module should be compiled, unless we
+dnl are linking with libunistring and its version is >= the given VERSION.
+dnl Defines an automake conditional LIBUNISTRING_COMPILE_$MODULE that is
+dnl true if the source files of Module should be compiled.
+dnl This macro is to be used for public libunistring API, not for
+dnl undocumented API.
+dnl
+dnl You have to bump the VERSION argument to the next projected version
+dnl number each time you make a change that affects the behaviour of the
+dnl functions defined in Module (even if the sources of Module itself do not
+dnl change).
+
+AC_DEFUN([gl_LIBUNISTRING_MODULE],
+[
+  AC_REQUIRE([gl_LIBUNISTRING_LIB_PREPARE])
+  dnl Use the variables HAVE_LIBUNISTRING, LIBUNISTRING_VERSION from
+  dnl gl_LIBUNISTRING_CORE if that macro has been run.
+  AM_CONDITIONAL(AS_TR_CPP([LIBUNISTRING_COMPILE_$2]),
+    [gl_LIBUNISTRING_VERSION_CMP([$1])])
+])
+
+dnl gl_LIBUNISTRING_LIBHEADER([VERSION], [HeaderFile])
+dnl Declares that HeaderFile should be created, unless we are linking
+dnl with libunistring and its version is >= the given VERSION.
+dnl HeaderFile should be relative to the lib directory and end in '.h'.
+dnl Prepares for substituting LIBUNISTRING_HEADERFILE (to HeaderFile or empty).
+dnl
+dnl When we are linking with the already installed libunistring and its version
+dnl is < VERSION, we create HeaderFile here, because we may compile functions
+dnl (via gl_LIBUNISTRING_MODULE above) that are not contained in the installed
+dnl version.
+dnl When we are linking with the already installed libunistring and its version
+dnl is > VERSION, we don't create HeaderFile here: it could cause compilation
+dnl errors in other libunistring header files if some types are missing.
+dnl
+dnl You have to bump the VERSION argument to the next projected version
+dnl number each time you make a non-comment change to the HeaderFile.
+
+AC_DEFUN([gl_LIBUNISTRING_LIBHEADER],
+[
+  AC_REQUIRE([gl_LIBUNISTRING_LIB_PREPARE])
+  dnl Use the variables HAVE_LIBUNISTRING, LIBUNISTRING_VERSION from
+  dnl gl_LIBUNISTRING_CORE if that macro has been run.
+  if gl_LIBUNISTRING_VERSION_CMP([$1]); then
+    LIBUNISTRING_[]AS_TR_CPP([$2])='$2'
+  else
+    LIBUNISTRING_[]AS_TR_CPP([$2])=
+  fi
+  AC_SUBST([LIBUNISTRING_]AS_TR_CPP([$2]))
+])
+
+dnl Miscellaneous preparations/initializations.
+
+AC_DEFUN([gl_LIBUNISTRING_LIB_PREPARE],
+[
+  dnl Ensure that HAVE_LIBUNISTRING is fully determined at this point.
+  m4_ifdef([gl_LIBUNISTRING], [AC_REQUIRE([gl_LIBUNISTRING])])
+
+  AC_REQUIRE([AC_PROG_AWK])
+
+dnl Sed expressions to extract the parts of a version number.
+changequote(,)
+gl_libunistring_sed_extract_major='/^[0-9]/{s/^\([0-9]*\).*/\1/p;q;}
+i\
+0
+q
+'
+gl_libunistring_sed_extract_minor='/^[0-9][0-9]*[.][0-9]/{s/^[0-9]*[.]\([0-9]*\).*/\1/p;q;}
+i\
+0
+q
+'
+gl_libunistring_sed_extract_subminor='/^[0-9][0-9]*[.][0-9][0-9]*[.][0-9]/{s/^[0-9]*[.][0-9]*[.]\([0-9]*\).*/\1/p;q;}
+i\
+0
+q
+'
+changequote([,])
+
+  if test "$HAVE_LIBUNISTRING" = yes; then
+    LIBUNISTRING_VERSION_MAJOR=`echo "$LIBUNISTRING_VERSION" | sed -n -e "$gl_libunistring_sed_extract_major"`
+    LIBUNISTRING_VERSION_MINOR=`echo "$LIBUNISTRING_VERSION" | sed -n -e "$gl_libunistring_sed_extract_minor"`
+    LIBUNISTRING_VERSION_SUBMINOR=`echo "$LIBUNISTRING_VERSION" | sed -n -e "$gl_libunistring_sed_extract_subminor"`
+  fi
+])
+
+dnl gl_LIBUNISTRING_VERSION_CMP([VERSION])
+dnl Expands to a shell statement that evaluates to true if LIBUNISTRING_VERSION
+dnl is less than the VERSION argument.
+AC_DEFUN([gl_LIBUNISTRING_VERSION_CMP],
+[ { test "$HAVE_LIBUNISTRING" != yes \
+    || {
+         dnl AS_LITERAL_IF exists and works fine since autoconf-2.59 at least.
+         AS_LITERAL_IF([$1],
+           [dnl This is the optimized variant, that assumes the argument is a literal:
+            m4_pushdef([requested_version_major],
+              [gl_LIBUNISTRING_ARG_OR_ZERO(m4_bpatsubst([$1], [^\([0-9]*\).*], [\1]), [])])
+            m4_pushdef([requested_version_minor],
+              [gl_LIBUNISTRING_ARG_OR_ZERO(m4_bpatsubst([$1], [^[0-9]*[.]\([0-9]*\).*], [\1]), [$1])])
+            m4_pushdef([requested_version_subminor],
+              [gl_LIBUNISTRING_ARG_OR_ZERO(m4_bpatsubst([$1], [^[0-9]*[.][0-9]*[.]\([0-9]*\).*], [\1]), [$1])])
+            test $LIBUNISTRING_VERSION_MAJOR -lt requested_version_major \
+            || { test $LIBUNISTRING_VERSION_MAJOR -eq requested_version_major \
+                 && { test $LIBUNISTRING_VERSION_MINOR -lt requested_version_minor \
+                      || { test $LIBUNISTRING_VERSION_MINOR -eq requested_version_minor \
+                           && test $LIBUNISTRING_VERSION_SUBMINOR -lt requested_version_subminor
+                         }
+                    }
+               }
+            m4_popdef([requested_version_subminor])
+            m4_popdef([requested_version_minor])
+            m4_popdef([requested_version_major])
+           ],
+           [dnl This is the unoptimized variant:
+            requested_version_major=`echo '$1' | sed -n -e "$gl_libunistring_sed_extract_major"`
+            requested_version_minor=`echo '$1' | sed -n -e "$gl_libunistring_sed_extract_minor"`
+            requested_version_subminor=`echo '$1' | sed -n -e "$gl_libunistring_sed_extract_subminor"`
+            test $LIBUNISTRING_VERSION_MAJOR -lt $requested_version_major \
+            || { test $LIBUNISTRING_VERSION_MAJOR -eq $requested_version_major \
+                 && { test $LIBUNISTRING_VERSION_MINOR -lt $requested_version_minor \
+                      || { test $LIBUNISTRING_VERSION_MINOR -eq $requested_version_minor \
+                           && test $LIBUNISTRING_VERSION_SUBMINOR -lt $requested_version_subminor
+                         }
+                    }
+               }
+           ])
+       }
+  }])
+
+dnl gl_LIBUNISTRING_ARG_OR_ZERO([ARG], [ORIG]) expands to ARG if it is not the
+dnl same as ORIG, otherwise to 0.
+m4_define([gl_LIBUNISTRING_ARG_OR_ZERO], [m4_if([$1], [$2], [0], [$1])])
diff --git a/m4/libunistring-optional.m4 b/m4/libunistring-optional.m4
new file mode 100644
index 0000000..f1a24c0
--- /dev/null
+++ b/m4/libunistring-optional.m4
@@ -0,0 +1,22 @@
+# libunistring-optional.m4 serial 1
+dnl Copyright (C) 2010-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl gl_LIBUNISTRING_OPTIONAL
+dnl Searches for an installed libunistring or uses the included source code
+dnl parts.
+dnl If found, it sets and AC_SUBSTs HAVE_LIBUNISTRING=yes and the LIBUNISTRING
+dnl and LTLIBUNISTRING variables and augments the CPPFLAGS variable, and
+dnl #defines HAVE_LIBUNISTRING to 1. Otherwise, it sets and AC_SUBSTs
+dnl HAVE_LIBUNISTRING=no and LIBUNISTRING and LTLIBUNISTRING to empty.
+
+AC_DEFUN([gl_LIBUNISTRING_OPTIONAL],
+[
+  dnl gl_LIBUNISTRING does a couple of extra things if this macro is used.
+  AC_REQUIRE([gl_LIBUNISTRING])
+
+  AC_MSG_CHECKING([whether to use the included libunistring])
+  AC_MSG_RESULT([$gl_libunistring_use_included])
+])
diff --git a/m4/libunistring.m4 b/m4/libunistring.m4
new file mode 100644
index 0000000..a0c36e3
--- /dev/null
+++ b/m4/libunistring.m4
@@ -0,0 +1,143 @@
+# libunistring.m4 serial 12
+dnl Copyright (C) 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_PREREQ([2.64])
+
+dnl gl_LIBUNISTRING
+dnl Searches for an installed libunistring.
+dnl If found, it sets and AC_SUBSTs HAVE_LIBUNISTRING=yes and the LIBUNISTRING
+dnl and LTLIBUNISTRING variables, sets the LIBUNISTRING_VERSION variable, and
+dnl augments the CPPFLAGS variable, and #defines HAVE_LIBUNISTRING to 1.
+dnl Otherwise, it sets and AC_SUBSTs HAVE_LIBUNISTRING=no and LIBUNISTRING and
+dnl LTLIBUNISTRING to empty.
+
+dnl Define gl_LIBUNISTRING using AC_DEFUN_ONCE, in order dnl to avoid warnings
+dnl like
+dnl "warning: AC_REQUIRE: `gl_LIBUNISTRING' was expanded before it was required".
+dnl This is tricky because of the way 'aclocal' is implemented:
+dnl - It requires defining an auxiliary macro whose name ends in AC_DEFUN.
+dnl   Otherwise aclocal's initial scan pass would miss the macro definition.
+dnl - It requires a line break inside the AC_DEFUN_ONCE and AC_DEFUN expansions.
+dnl   Otherwise aclocal would emit many "Use of uninitialized value $1"
+dnl   warnings.
+AC_DEFUN_ONCE([gl_LIBUNISTRING],
+[
+  AC_BEFORE([$0], [gl_LIBUNISTRING_MODULE])
+  AC_BEFORE([$0], [gl_LIBUNISTRING_LIBHEADER])
+  AC_BEFORE([$0], [gl_LIBUNISTRING_LIB_PREPARE])
+
+  m4_ifdef([gl_LIBUNISTRING_OPTIONAL],
+    [
+      AC_MSG_CHECKING([whether included libunistring is requested])
+      AC_ARG_WITH([included-libunistring],
+        [  --with-included-libunistring  use the libunistring parts included here],
+        [gl_libunistring_force_included=$withval],
+        [gl_libunistring_force_included=no])
+      AC_MSG_RESULT([$gl_libunistring_force_included])
+      gl_libunistring_use_included="$gl_libunistring_force_included"
+      if test "$gl_libunistring_use_included" = yes; then
+        dnl Assume that libunistring is not installed until some other macro
+        dnl explicitly invokes gl_LIBUNISTRING_CORE.
+        if test -z "$HAVE_LIBUNISTRING"; then
+          HAVE_LIBUNISTRING=no
+        fi
+        LIBUNISTRING=
+        LTLIBUNISTRING=
+      else
+        gl_LIBUNISTRING_CORE
+        if test $HAVE_LIBUNISTRING = no; then
+          gl_libunistring_use_included=yes
+          LIBUNISTRING=
+          LTLIBUNISTRING=
+        fi
+      fi
+    ],
+    [gl_LIBUNISTRING_CORE])
+])
+
+AC_DEFUN([gl_LIBUNISTRING_CORE],
+[
+  AC_REQUIRE([AM_ICONV])
+  if test -n "$LIBICONV"; then
+    dnl First, try to link without -liconv. libunistring often depends on
+    dnl libiconv, but we don't know (and often don't need to know) where
+    dnl libiconv is installed.
+    AC_LIB_HAVE_LINKFLAGS([unistring], [],
+      [#include <uniconv.h>], [u8_strconv_from_locale((char*)0);],
+      [no, trying again together with libiconv])
+    if test "$ac_cv_libunistring" != yes; then
+      dnl Second try, with -liconv.
+      dnl We have to erase the cached result of the first AC_LIB_HAVE_LINKFLAGS
+      dnl invocation, otherwise the second one will not be run.
+      unset ac_cv_libunistring
+      glus_save_LIBS="$LIBS"
+      LIBS="$LIBS $LIBICONV"
+      AC_LIB_HAVE_LINKFLAGS([unistring], [],
+        [#include <uniconv.h>], [u8_strconv_from_locale((char*)0);],
+        [no, consider installing GNU libunistring])
+      if test -n "$LIBUNISTRING"; then
+        LIBUNISTRING="$LIBUNISTRING $LIBICONV"
+        LTLIBUNISTRING="$LTLIBUNISTRING $LTLIBICONV"
+      fi
+      LIBS="$glus_save_LIBS"
+    fi
+  else
+    AC_LIB_HAVE_LINKFLAGS([unistring], [],
+      [#include <uniconv.h>], [u8_strconv_from_locale((char*)0);],
+      [no, consider installing GNU libunistring])
+  fi
+  if test $HAVE_LIBUNISTRING = yes; then
+    dnl Determine the installed version.
+    AC_CACHE_CHECK([for libunistring version], [gl_cv_libunistring_version],
+      [AC_COMPUTE_INT([gl_libunistring_hexversion],
+                      [_LIBUNISTRING_VERSION],
+                      [#include <unistring/version.h>])
+       dnl Versions <= 0.9.3 had a hexversion of 0x0009.
+       dnl Use other tests to distinguish them.
+       if test $gl_libunistring_hexversion = 9; then
+         dnl Version 0.9.2 introduced the header <unistring/cdefs.h>.
+         AC_COMPILE_IFELSE(
+           [AC_LANG_PROGRAM([[#include <unistring/cdefs.h>]], [[]])],
+           [gl_cv_libunistring_version092=true],
+           [gl_cv_libunistring_version092=false])
+         if $gl_cv_libunistring_version092; then
+           dnl Version 0.9.3 changed a comment in <unistr.h>.
+           gl_ABSOLUTE_HEADER_ONE([unistr.h])
+           if test -n "$gl_cv_absolute_unistr_h" \
+              && grep 'Copy no more than N units of SRC to DEST.  Return a pointer' $gl_cv_absolute_unistr_h > /dev/null; then
+             dnl Detected version 0.9.3.
+             gl_libunistring_hexversion=2307
+           else
+             dnl Detected version 0.9.2.
+             gl_libunistring_hexversion=2306
+           fi
+         else
+           dnl Version 0.9.1 introduced the type casing_suffix_context_t.
+           AC_COMPILE_IFELSE(
+             [AC_LANG_PROGRAM(
+                [[#include <unicase.h>
+                  casing_suffix_context_t ct;]],
+                [[]])],
+             [gl_cv_libunistring_version091=true],
+             [gl_cv_libunistring_version091=false])
+           if $gl_cv_libunistring_version091; then
+             dnl Detected version 0.9.1.
+             gl_libunistring_hexversion=2305
+           else
+             dnl Detected version 0.9.
+             gl_libunistring_hexversion=2304
+           fi
+         fi
+       fi
+       dnl Transform into the usual major.minor.subminor notation.
+       gl_libunistring_major=`expr $gl_libunistring_hexversion / 65536`
+       gl_libunistring_minor=`expr $gl_libunistring_hexversion / 256 % 256`
+       gl_libunistring_subminor=`expr $gl_libunistring_hexversion % 256`
+       gl_cv_libunistring_version="$gl_libunistring_major.$gl_libunistring_minor.$gl_libunistring_subminor"
+      ])
+    LIBUNISTRING_VERSION="$gl_cv_libunistring_version"
+  fi
+])
diff --git a/m4/limits-h.m4 b/m4/limits-h.m4
new file mode 100644
index 0000000..0b4f092
--- /dev/null
+++ b/m4/limits-h.m4
@@ -0,0 +1,43 @@
+dnl Check whether limits.h has needed features.
+
+dnl Copyright 2016-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl From Paul Eggert.
+
+AC_DEFUN_ONCE([gl_LIMITS_H],
+[
+  gl_CHECK_NEXT_HEADERS([limits.h])
+
+  AC_CACHE_CHECK([whether limits.h has LLONG_MAX, WORD_BIT, ULLONG_WIDTH etc.],
+    [gl_cv_header_limits_width],
+    [AC_COMPILE_IFELSE(
+       [AC_LANG_PROGRAM(
+          [[#ifndef __STDC_WANT_IEC_60559_BFP_EXT__
+             #define __STDC_WANT_IEC_60559_BFP_EXT__ 1
+            #endif
+            #include <limits.h>
+            long long llm = LLONG_MAX;
+            int wb = WORD_BIT;
+            int ullw = ULLONG_WIDTH;
+          ]])],
+       [gl_cv_header_limits_width=yes],
+       [gl_cv_header_limits_width=no])])
+  if test "$gl_cv_header_limits_width" = yes; then
+    LIMITS_H=
+  else
+    LIMITS_H=limits.h
+  fi
+  AC_SUBST([LIMITS_H])
+  AM_CONDITIONAL([GL_GENERATE_LIMITS_H], [test -n "$LIMITS_H"])
+])
+
+dnl Unconditionally enables the replacement of <limits.h>.
+AC_DEFUN([gl_REPLACE_LIMITS_H],
+[
+  AC_REQUIRE([gl_LIMITS_H])
+  LIMITS_H='limits.h'
+  AM_CONDITIONAL([GL_GENERATE_LIMITS_H], [test -n "$LIMITS_H"])
+])
diff --git a/m4/link.m4 b/m4/link.m4
new file mode 100644
index 0000000..0d1de80
--- /dev/null
+++ b/m4/link.m4
@@ -0,0 +1,58 @@
+# link.m4 serial 11
+dnl Copyright (C) 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_LINK],
+[
+  AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_CHECK_FUNCS_ONCE([link])
+  if test $ac_cv_func_link = no; then
+    HAVE_LINK=0
+  else
+    AC_CACHE_CHECK([whether link obeys POSIX],
+      [gl_cv_func_link_works],
+      [touch conftest.a
+       # Assume that if we have lstat, we can also check symlinks.
+       if test $ac_cv_func_lstat = yes; then
+         ln -s conftest.a conftest.lnk
+       fi
+       AC_RUN_IFELSE(
+         [AC_LANG_PROGRAM(
+           [[#include <unistd.h>
+             #include <stdio.h>
+           ]],
+           [[int result = 0;
+             if (!link ("conftest.a", "conftest.b/"))
+               result |= 1;
+#if HAVE_LSTAT
+             if (!link ("conftest.lnk/", "conftest.b"))
+               result |= 2;
+             if (rename ("conftest.a", "conftest.b"))
+               result |= 4;
+             if (!link ("conftest.b", "conftest.lnk"))
+               result |= 8;
+#endif
+             return result;
+           ]])],
+         [gl_cv_func_link_works=yes], [gl_cv_func_link_works=no],
+         [case "$host_os" in
+                             # Guess yes on Linux systems.
+            linux-* | linux) gl_cv_func_link_works="guessing yes" ;;
+                             # Guess yes on glibc systems.
+            *-gnu* | gnu*)   gl_cv_func_link_works="guessing yes" ;;
+                             # If we don't know, obey --enable-cross-guesses.
+            *)               gl_cv_func_link_works="$gl_cross_guess_normal" ;;
+          esac
+         ])
+       rm -f conftest.a conftest.b conftest.lnk])
+    case "$gl_cv_func_link_works" in
+      *yes) ;;
+      *)
+        REPLACE_LINK=1
+        ;;
+    esac
+  fi
+])
diff --git a/m4/localcharset.m4 b/m4/localcharset.m4
new file mode 100644
index 0000000..9d21c4f
--- /dev/null
+++ b/m4/localcharset.m4
@@ -0,0 +1,11 @@
+# localcharset.m4 serial 8
+dnl Copyright (C) 2002, 2004, 2006, 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_LOCALCHARSET],
+[
+  dnl Prerequisites of lib/localcharset.c.
+  AC_REQUIRE([AM_LANGINFO_CODESET])
+])
diff --git a/m4/locale-fr.m4 b/m4/locale-fr.m4
new file mode 100644
index 0000000..406951f
--- /dev/null
+++ b/m4/locale-fr.m4
@@ -0,0 +1,253 @@
+# locale-fr.m4 serial 20
+dnl Copyright (C) 2003, 2005-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl From Bruno Haible.
+
+dnl Determine the name of a french locale with traditional encoding.
+AC_DEFUN([gt_LOCALE_FR],
+[
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  AC_REQUIRE([AM_LANGINFO_CODESET])
+  AC_CACHE_CHECK([for a traditional french locale], [gt_cv_locale_fr], [
+    AC_LANG_CONFTEST([AC_LANG_SOURCE([[
+#include <locale.h>
+#include <time.h>
+#if HAVE_LANGINFO_CODESET
+# include <langinfo.h>
+#endif
+#include <stdlib.h>
+#include <string.h>
+struct tm t;
+char buf[16];
+int main () {
+  /* On BeOS and Haiku, locales are not implemented in libc.  Rather, libintl
+     imitates locale dependent behaviour by looking at the environment
+     variables, and all locales use the UTF-8 encoding.  */
+#if defined __BEOS__ || defined __HAIKU__
+  return 1;
+#else
+  /* Check whether the given locale name is recognized by the system.  */
+# if defined _WIN32 && !defined __CYGWIN__
+  /* On native Windows, setlocale(category, "") looks at the system settings,
+     not at the environment variables.  Also, when an encoding suffix such
+     as ".65001" or ".54936" is specified, it succeeds but sets the LC_CTYPE
+     category of the locale to "C".  */
+  if (setlocale (LC_ALL, getenv ("LC_ALL")) == NULL
+      || strcmp (setlocale (LC_CTYPE, NULL), "C") == 0)
+    return 1;
+# else
+  if (setlocale (LC_ALL, "") == NULL) return 1;
+# endif
+  /* Check whether nl_langinfo(CODESET) is nonempty and not "ASCII" or "646".
+     On Mac OS X 10.3.5 (Darwin 7.5) in the fr_FR locale, nl_langinfo(CODESET)
+     is empty, and the behaviour of Tcl 8.4 in this locale is not useful.
+     On OpenBSD 4.0, when an unsupported locale is specified, setlocale()
+     succeeds but then nl_langinfo(CODESET) is "646". In this situation,
+     some unit tests fail.
+     On MirBSD 10, when an unsupported locale is specified, setlocale()
+     succeeds but then nl_langinfo(CODESET) is "UTF-8".  */
+# if HAVE_LANGINFO_CODESET
+  {
+    const char *cs = nl_langinfo (CODESET);
+    if (cs[0] == '\0' || strcmp (cs, "ASCII") == 0 || strcmp (cs, "646") == 0
+        || strcmp (cs, "UTF-8") == 0)
+      return 1;
+  }
+# endif
+# ifdef __CYGWIN__
+  /* On Cygwin, avoid locale names without encoding suffix, because the
+     locale_charset() function relies on the encoding suffix.  Note that
+     LC_ALL is set on the command line.  */
+  if (strchr (getenv ("LC_ALL"), '.') == NULL) return 1;
+# endif
+  /* Check whether in the abbreviation of the second month, the second
+     character (should be U+00E9: LATIN SMALL LETTER E WITH ACUTE) is only
+     one byte long. This excludes the UTF-8 encoding.  */
+  t.tm_year = 1975 - 1900; t.tm_mon = 2 - 1; t.tm_mday = 4;
+  if (strftime (buf, sizeof (buf), "%b", &t) < 3 || buf[2] != 'v') return 1;
+# if !defined __BIONIC__ /* Bionic libc's 'struct lconv' is just a dummy.  */
+  /* Check whether the decimal separator is a comma.
+     On NetBSD 3.0 in the fr_FR.ISO8859-1 locale, localeconv()->decimal_point
+     are nl_langinfo(RADIXCHAR) are both ".".  */
+  if (localeconv () ->decimal_point[0] != ',') return 1;
+# endif
+  return 0;
+#endif
+}
+      ]])])
+    if AC_TRY_EVAL([ac_link]) && test -s conftest$ac_exeext; then
+      case "$host_os" in
+        # Handle native Windows specially, because there setlocale() interprets
+        # "ar" as "Arabic" or "Arabic_Saudi Arabia.1256",
+        # "fr" or "fra" as "French" or "French_France.1252",
+        # "ge"(!) or "deu"(!) as "German" or "German_Germany.1252",
+        # "ja" as "Japanese" or "Japanese_Japan.932",
+        # and similar.
+        mingw*)
+          # Test for the native Windows locale name.
+          if (LC_ALL=French_France.1252 LC_TIME= LC_CTYPE= ./conftest; exit) 2>/dev/null; then
+            gt_cv_locale_fr=French_France.1252
+          else
+            # None found.
+            gt_cv_locale_fr=none
+          fi
+          ;;
+        *)
+          # Setting LC_ALL is not enough. Need to set LC_TIME to empty, because
+          # otherwise on Mac OS X 10.3.5 the LC_TIME=C from the beginning of the
+          # configure script would override the LC_ALL setting. Likewise for
+          # LC_CTYPE, which is also set at the beginning of the configure script.
+          # Test for the usual locale name.
+          if (LC_ALL=fr_FR LC_TIME= LC_CTYPE= ./conftest; exit) 2>/dev/null; then
+            gt_cv_locale_fr=fr_FR
+          else
+            # Test for the locale name with explicit encoding suffix.
+            if (LC_ALL=fr_FR.ISO-8859-1 LC_TIME= LC_CTYPE= ./conftest; exit) 2>/dev/null; then
+              gt_cv_locale_fr=fr_FR.ISO-8859-1
+            else
+              # Test for the AIX, OSF/1, FreeBSD, NetBSD, OpenBSD locale name.
+              if (LC_ALL=fr_FR.ISO8859-1 LC_TIME= LC_CTYPE= ./conftest; exit) 2>/dev/null; then
+                gt_cv_locale_fr=fr_FR.ISO8859-1
+              else
+                # Test for the HP-UX locale name.
+                if (LC_ALL=fr_FR.iso88591 LC_TIME= LC_CTYPE= ./conftest; exit) 2>/dev/null; then
+                  gt_cv_locale_fr=fr_FR.iso88591
+                else
+                  # Test for the Solaris 7 locale name.
+                  if (LC_ALL=fr LC_TIME= LC_CTYPE= ./conftest; exit) 2>/dev/null; then
+                    gt_cv_locale_fr=fr
+                  else
+                    # None found.
+                    gt_cv_locale_fr=none
+                  fi
+                fi
+              fi
+            fi
+          fi
+          ;;
+      esac
+    fi
+    rm -fr conftest*
+  ])
+  LOCALE_FR=$gt_cv_locale_fr
+  AC_SUBST([LOCALE_FR])
+])
+
+dnl Determine the name of a french locale with UTF-8 encoding.
+AC_DEFUN([gt_LOCALE_FR_UTF8],
+[
+  AC_REQUIRE([AM_LANGINFO_CODESET])
+  AC_CACHE_CHECK([for a french Unicode locale], [gt_cv_locale_fr_utf8], [
+    AC_LANG_CONFTEST([AC_LANG_SOURCE([[
+#include <locale.h>
+#include <time.h>
+#if HAVE_LANGINFO_CODESET
+# include <langinfo.h>
+#endif
+#include <stdlib.h>
+#include <string.h>
+struct tm t;
+char buf[16];
+int main () {
+  /* On BeOS and Haiku, locales are not implemented in libc.  Rather, libintl
+     imitates locale dependent behaviour by looking at the environment
+     variables, and all locales use the UTF-8 encoding.  */
+#if !(defined __BEOS__ || defined __HAIKU__)
+  /* Check whether the given locale name is recognized by the system.  */
+# if defined _WIN32 && !defined __CYGWIN__
+  /* On native Windows, setlocale(category, "") looks at the system settings,
+     not at the environment variables.  Also, when an encoding suffix such
+     as ".65001" or ".54936" is specified, it succeeds but sets the LC_CTYPE
+     category of the locale to "C".  */
+  if (setlocale (LC_ALL, getenv ("LC_ALL")) == NULL
+      || strcmp (setlocale (LC_CTYPE, NULL), "C") == 0)
+    return 1;
+# else
+  if (setlocale (LC_ALL, "") == NULL) return 1;
+# endif
+  /* Check whether nl_langinfo(CODESET) is nonempty and not "ASCII" or "646".
+     On Mac OS X 10.3.5 (Darwin 7.5) in the fr_FR locale, nl_langinfo(CODESET)
+     is empty, and the behaviour of Tcl 8.4 in this locale is not useful.
+     On OpenBSD 4.0, when an unsupported locale is specified, setlocale()
+     succeeds but then nl_langinfo(CODESET) is "646". In this situation,
+     some unit tests fail.  */
+# if HAVE_LANGINFO_CODESET
+  {
+    const char *cs = nl_langinfo (CODESET);
+    if (cs[0] == '\0' || strcmp (cs, "ASCII") == 0 || strcmp (cs, "646") == 0)
+      return 1;
+  }
+# endif
+# ifdef __CYGWIN__
+  /* On Cygwin, avoid locale names without encoding suffix, because the
+     locale_charset() function relies on the encoding suffix.  Note that
+     LC_ALL is set on the command line.  */
+  if (strchr (getenv ("LC_ALL"), '.') == NULL) return 1;
+# endif
+  /* Check whether in the abbreviation of the second month, the second
+     character (should be U+00E9: LATIN SMALL LETTER E WITH ACUTE) is
+     two bytes long, with UTF-8 encoding.  */
+  t.tm_year = 1975 - 1900; t.tm_mon = 2 - 1; t.tm_mday = 4;
+  if (strftime (buf, sizeof (buf), "%b", &t) < 4
+      || buf[1] != (char) 0xc3 || buf[2] != (char) 0xa9 || buf[3] != 'v')
+    return 1;
+#endif
+#if !defined __BIONIC__ /* Bionic libc's 'struct lconv' is just a dummy.  */
+  /* Check whether the decimal separator is a comma.
+     On NetBSD 3.0 in the fr_FR.ISO8859-1 locale, localeconv()->decimal_point
+     are nl_langinfo(RADIXCHAR) are both ".".  */
+  if (localeconv () ->decimal_point[0] != ',') return 1;
+#endif
+  return 0;
+}
+      ]])])
+    if AC_TRY_EVAL([ac_link]) && test -s conftest$ac_exeext; then
+      case "$host_os" in
+        # Handle native Windows specially, because there setlocale() interprets
+        # "ar" as "Arabic" or "Arabic_Saudi Arabia.1256",
+        # "fr" or "fra" as "French" or "French_France.1252",
+        # "ge"(!) or "deu"(!) as "German" or "German_Germany.1252",
+        # "ja" as "Japanese" or "Japanese_Japan.932",
+        # and similar.
+        mingw*)
+          # Test for the hypothetical native Windows locale name.
+          if (LC_ALL=French_France.65001 LC_TIME= LC_CTYPE= ./conftest; exit) 2>/dev/null; then
+            gt_cv_locale_fr_utf8=French_France.65001
+          else
+            # None found.
+            gt_cv_locale_fr_utf8=none
+          fi
+          ;;
+        *)
+          # Setting LC_ALL is not enough. Need to set LC_TIME to empty, because
+          # otherwise on Mac OS X 10.3.5 the LC_TIME=C from the beginning of the
+          # configure script would override the LC_ALL setting. Likewise for
+          # LC_CTYPE, which is also set at the beginning of the configure script.
+          # Test for the usual locale name.
+          if (LC_ALL=fr_FR LC_TIME= LC_CTYPE= ./conftest; exit) 2>/dev/null; then
+            gt_cv_locale_fr_utf8=fr_FR
+          else
+            # Test for the locale name with explicit encoding suffix.
+            if (LC_ALL=fr_FR.UTF-8 LC_TIME= LC_CTYPE= ./conftest; exit) 2>/dev/null; then
+              gt_cv_locale_fr_utf8=fr_FR.UTF-8
+            else
+              # Test for the Solaris 7 locale name.
+              if (LC_ALL=fr.UTF-8 LC_TIME= LC_CTYPE= ./conftest; exit) 2>/dev/null; then
+                gt_cv_locale_fr_utf8=fr.UTF-8
+              else
+                # None found.
+                gt_cv_locale_fr_utf8=none
+              fi
+            fi
+          fi
+          ;;
+      esac
+    fi
+    rm -fr conftest*
+  ])
+  LOCALE_FR_UTF8=$gt_cv_locale_fr_utf8
+  AC_SUBST([LOCALE_FR_UTF8])
+])
diff --git a/m4/locale-ja.m4 b/m4/locale-ja.m4
new file mode 100644
index 0000000..31e95b8
--- /dev/null
+++ b/m4/locale-ja.m4
@@ -0,0 +1,143 @@
+# locale-ja.m4 serial 15
+dnl Copyright (C) 2003, 2005-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl From Bruno Haible.
+
+dnl Determine the name of a japanese locale with EUC-JP encoding.
+AC_DEFUN([gt_LOCALE_JA],
+[
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  AC_REQUIRE([AM_LANGINFO_CODESET])
+  AC_CACHE_CHECK([for a traditional japanese locale], [gt_cv_locale_ja], [
+    AC_LANG_CONFTEST([AC_LANG_SOURCE([[
+#include <locale.h>
+#include <time.h>
+#if HAVE_LANGINFO_CODESET
+# include <langinfo.h>
+#endif
+#include <stdlib.h>
+#include <string.h>
+struct tm t;
+char buf[16];
+int main ()
+{
+  /* On BeOS and Haiku, locales are not implemented in libc.  Rather, libintl
+     imitates locale dependent behaviour by looking at the environment
+     variables, and all locales use the UTF-8 encoding.  */
+#if defined __BEOS__ || defined __HAIKU__
+  return 1;
+#else
+  /* Check whether the given locale name is recognized by the system.  */
+# if defined _WIN32 && !defined __CYGWIN__
+  /* On native Windows, setlocale(category, "") looks at the system settings,
+     not at the environment variables.  Also, when an encoding suffix such
+     as ".65001" or ".54936" is specified, it succeeds but sets the LC_CTYPE
+     category of the locale to "C".  */
+  if (setlocale (LC_ALL, getenv ("LC_ALL")) == NULL
+      || strcmp (setlocale (LC_CTYPE, NULL), "C") == 0)
+    return 1;
+# else
+  if (setlocale (LC_ALL, "") == NULL) return 1;
+# endif
+  /* Check whether nl_langinfo(CODESET) is nonempty and not "ASCII" or "646".
+     On Mac OS X 10.3.5 (Darwin 7.5) in the fr_FR locale, nl_langinfo(CODESET)
+     is empty, and the behaviour of Tcl 8.4 in this locale is not useful.
+     On OpenBSD 4.0, when an unsupported locale is specified, setlocale()
+     succeeds but then nl_langinfo(CODESET) is "646". In this situation,
+     some unit tests fail.
+     On MirBSD 10, when an unsupported locale is specified, setlocale()
+     succeeds but then nl_langinfo(CODESET) is "UTF-8".  */
+# if HAVE_LANGINFO_CODESET
+  {
+    const char *cs = nl_langinfo (CODESET);
+    if (cs[0] == '\0' || strcmp (cs, "ASCII") == 0 || strcmp (cs, "646") == 0
+        || strcmp (cs, "UTF-8") == 0)
+      return 1;
+  }
+# endif
+# ifdef __CYGWIN__
+  /* On Cygwin, avoid locale names without encoding suffix, because the
+     locale_charset() function relies on the encoding suffix.  Note that
+     LC_ALL is set on the command line.  */
+  if (strchr (getenv ("LC_ALL"), '.') == NULL) return 1;
+# endif
+  /* Check whether MB_CUR_MAX is > 1.  This excludes the dysfunctional locales
+     on Cygwin 1.5.x.  */
+  if (MB_CUR_MAX == 1)
+    return 1;
+  /* Check whether in a month name, no byte in the range 0x80..0x9F occurs.
+     This excludes the UTF-8 encoding (except on MirBSD).  */
+  {
+    const char *p;
+    t.tm_year = 1975 - 1900; t.tm_mon = 2 - 1; t.tm_mday = 4;
+    if (strftime (buf, sizeof (buf), "%B", &t) < 2) return 1;
+    for (p = buf; *p != '\0'; p++)
+      if ((unsigned char) *p >= 0x80 && (unsigned char) *p < 0xa0)
+        return 1;
+  }
+  return 0;
+#endif
+}
+      ]])])
+    if AC_TRY_EVAL([ac_link]) && test -s conftest$ac_exeext; then
+      case "$host_os" in
+        # Handle native Windows specially, because there setlocale() interprets
+        # "ar" as "Arabic" or "Arabic_Saudi Arabia.1256",
+        # "fr" or "fra" as "French" or "French_France.1252",
+        # "ge"(!) or "deu"(!) as "German" or "German_Germany.1252",
+        # "ja" as "Japanese" or "Japanese_Japan.932",
+        # and similar.
+        mingw*)
+          # Note that on native Windows, the Japanese locale is
+          # Japanese_Japan.932, and CP932 is very different from EUC-JP, so we
+          # cannot use it here.
+          gt_cv_locale_ja=none
+          ;;
+        *)
+          # Setting LC_ALL is not enough. Need to set LC_TIME to empty, because
+          # otherwise on Mac OS X 10.3.5 the LC_TIME=C from the beginning of the
+          # configure script would override the LC_ALL setting. Likewise for
+          # LC_CTYPE, which is also set at the beginning of the configure script.
+          # Test for the AIX locale name.
+          if (LC_ALL=ja_JP LC_TIME= LC_CTYPE= ./conftest; exit) 2>/dev/null; then
+            gt_cv_locale_ja=ja_JP
+          else
+            # Test for the locale name with explicit encoding suffix.
+            if (LC_ALL=ja_JP.EUC-JP LC_TIME= LC_CTYPE= ./conftest; exit) 2>/dev/null; then
+              gt_cv_locale_ja=ja_JP.EUC-JP
+            else
+              # Test for the HP-UX, OSF/1, NetBSD locale name.
+              if (LC_ALL=ja_JP.eucJP LC_TIME= LC_CTYPE= ./conftest; exit) 2>/dev/null; then
+                gt_cv_locale_ja=ja_JP.eucJP
+              else
+                # Test for the IRIX, FreeBSD locale name.
+                if (LC_ALL=ja_JP.EUC LC_TIME= LC_CTYPE= ./conftest; exit) 2>/dev/null; then
+                  gt_cv_locale_ja=ja_JP.EUC
+                else
+                  # Test for the Solaris 7 locale name.
+                  if (LC_ALL=ja LC_TIME= LC_CTYPE= ./conftest; exit) 2>/dev/null; then
+                    gt_cv_locale_ja=ja
+                  else
+                    # Special test for NetBSD 1.6.
+                    if test -f /usr/share/locale/ja_JP.eucJP/LC_CTYPE; then
+                      gt_cv_locale_ja=ja_JP.eucJP
+                    else
+                      # None found.
+                      gt_cv_locale_ja=none
+                    fi
+                  fi
+                fi
+              fi
+            fi
+          fi
+          ;;
+      esac
+    fi
+    rm -fr conftest*
+  ])
+  LOCALE_JA=$gt_cv_locale_ja
+  AC_SUBST([LOCALE_JA])
+])
diff --git a/m4/locale-zh.m4 b/m4/locale-zh.m4
new file mode 100644
index 0000000..c60883c
--- /dev/null
+++ b/m4/locale-zh.m4
@@ -0,0 +1,137 @@
+# locale-zh.m4 serial 15
+dnl Copyright (C) 2003, 2005-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl From Bruno Haible.
+
+dnl Determine the name of a chinese locale with GB18030 encoding.
+AC_DEFUN([gt_LOCALE_ZH_CN],
+[
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  AC_REQUIRE([AM_LANGINFO_CODESET])
+  AC_CACHE_CHECK([for a transitional chinese locale], [gt_cv_locale_zh_CN], [
+    AC_LANG_CONFTEST([AC_LANG_SOURCE([[
+#include <locale.h>
+#include <stdlib.h>
+#include <time.h>
+#if HAVE_LANGINFO_CODESET
+# include <langinfo.h>
+#endif
+#include <stdlib.h>
+#include <string.h>
+struct tm t;
+char buf[16];
+int main ()
+{
+  /* On BeOS and Haiku, locales are not implemented in libc.  Rather, libintl
+     imitates locale dependent behaviour by looking at the environment
+     variables, and all locales use the UTF-8 encoding.  */
+#if defined __BEOS__ || defined __HAIKU__
+  return 1;
+#else
+  /* Check whether the given locale name is recognized by the system.  */
+# if defined _WIN32 && !defined __CYGWIN__
+  /* On native Windows, setlocale(category, "") looks at the system settings,
+     not at the environment variables.  Also, when an encoding suffix such
+     as ".65001" or ".54936" is specified, it succeeds but sets the LC_CTYPE
+     category of the locale to "C".  */
+  if (setlocale (LC_ALL, getenv ("LC_ALL")) == NULL
+      || strcmp (setlocale (LC_CTYPE, NULL), "C") == 0)
+    return 1;
+# else
+  if (setlocale (LC_ALL, "") == NULL) return 1;
+# endif
+  /* Check whether nl_langinfo(CODESET) is nonempty and not "ASCII" or "646".
+     On Mac OS X 10.3.5 (Darwin 7.5) in the fr_FR locale, nl_langinfo(CODESET)
+     is empty, and the behaviour of Tcl 8.4 in this locale is not useful.
+     On OpenBSD 4.0, when an unsupported locale is specified, setlocale()
+     succeeds but then nl_langinfo(CODESET) is "646". In this situation,
+     some unit tests fail.
+     On MirBSD 10, when an unsupported locale is specified, setlocale()
+     succeeds but then nl_langinfo(CODESET) is "UTF-8".  */
+# if HAVE_LANGINFO_CODESET
+  {
+    const char *cs = nl_langinfo (CODESET);
+    if (cs[0] == '\0' || strcmp (cs, "ASCII") == 0 || strcmp (cs, "646") == 0
+        || strcmp (cs, "UTF-8") == 0)
+      return 1;
+  }
+# endif
+# ifdef __CYGWIN__
+  /* On Cygwin, avoid locale names without encoding suffix, because the
+     locale_charset() function relies on the encoding suffix.  Note that
+     LC_ALL is set on the command line.  */
+  if (strchr (getenv ("LC_ALL"), '.') == NULL) return 1;
+# endif
+  /* Check whether in a month name, no byte in the range 0x80..0x9F occurs.
+     This excludes the UTF-8 encoding (except on MirBSD).  */
+  {
+    const char *p;
+    t.tm_year = 1975 - 1900; t.tm_mon = 2 - 1; t.tm_mday = 4;
+    if (strftime (buf, sizeof (buf), "%B", &t) < 2) return 1;
+    for (p = buf; *p != '\0'; p++)
+      if ((unsigned char) *p >= 0x80 && (unsigned char) *p < 0xa0)
+        return 1;
+  }
+  /* Check whether a typical GB18030 multibyte sequence is recognized as a
+     single wide character.  This excludes the GB2312 and GBK encodings.  */
+  if (mblen ("\203\062\332\066", 5) != 4)
+    return 1;
+  return 0;
+#endif
+}
+      ]])])
+    if AC_TRY_EVAL([ac_link]) && test -s conftest$ac_exeext; then
+      case "$host_os" in
+        # Handle native Windows specially, because there setlocale() interprets
+        # "ar" as "Arabic" or "Arabic_Saudi Arabia.1256",
+        # "fr" or "fra" as "French" or "French_France.1252",
+        # "ge"(!) or "deu"(!) as "German" or "German_Germany.1252",
+        # "ja" as "Japanese" or "Japanese_Japan.932",
+        # and similar.
+        mingw*)
+          # Test for the hypothetical native Windows locale name.
+          if (LC_ALL=Chinese_China.54936 LC_TIME= LC_CTYPE= ./conftest; exit) 2>/dev/null; then
+            gt_cv_locale_zh_CN=Chinese_China.54936
+          else
+            # None found.
+            gt_cv_locale_zh_CN=none
+          fi
+          ;;
+        solaris2.8)
+          # On Solaris 8, the locales zh_CN.GB18030, zh_CN.GBK, zh.GBK are
+          # broken. One witness is the test case in gl_MBRTOWC_SANITYCHECK.
+          # Another witness is that "LC_ALL=zh_CN.GB18030 bash -c true" dumps core.
+          gt_cv_locale_zh_CN=none
+          ;;
+        *)
+          # Setting LC_ALL is not enough. Need to set LC_TIME to empty, because
+          # otherwise on Mac OS X 10.3.5 the LC_TIME=C from the beginning of the
+          # configure script would override the LC_ALL setting. Likewise for
+          # LC_CTYPE, which is also set at the beginning of the configure script.
+          # Test for the locale name without encoding suffix.
+          if (LC_ALL=zh_CN LC_TIME= LC_CTYPE= ./conftest; exit) 2>/dev/null; then
+            gt_cv_locale_zh_CN=zh_CN
+          else
+            # Test for the locale name with explicit encoding suffix.
+            if (LC_ALL=zh_CN.GB18030 LC_TIME= LC_CTYPE= ./conftest; exit) 2>/dev/null; then
+              gt_cv_locale_zh_CN=zh_CN.GB18030
+            else
+              # None found.
+              gt_cv_locale_zh_CN=none
+            fi
+          fi
+          ;;
+      esac
+    else
+      # If there was a link error, due to mblen(), the system is so old that
+      # it certainly doesn't have a chinese locale.
+      gt_cv_locale_zh_CN=none
+    fi
+    rm -fr conftest*
+  ])
+  LOCALE_ZH_CN=$gt_cv_locale_zh_CN
+  AC_SUBST([LOCALE_ZH_CN])
+])
diff --git a/m4/locale_h.m4 b/m4/locale_h.m4
new file mode 100644
index 0000000..32494cf
--- /dev/null
+++ b/m4/locale_h.m4
@@ -0,0 +1,158 @@
+# locale_h.m4 serial 24
+dnl Copyright (C) 2007, 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_LOCALE_H],
+[
+  dnl Use AC_REQUIRE here, so that the default behavior below is expanded
+  dnl once only, before all statements that occur in other macros.
+  AC_REQUIRE([gl_LOCALE_H_DEFAULTS])
+
+  dnl Persuade glibc <locale.h> to define locale_t and the int_p_*, int_n_*
+  dnl members of 'struct lconv'.
+  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+
+  dnl If <stddef.h> is replaced, then <locale.h> must also be replaced.
+  AC_REQUIRE([gl_STDDEF_H])
+
+  AC_REQUIRE([gl_LOCALE_T])
+
+  dnl Solaris 11.0 defines the int_p_*, int_n_* members of 'struct lconv'
+  dnl only if _LCONV_C99 is defined.
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  case "$host_os" in
+    solaris*)
+      AC_DEFINE([_LCONV_C99], [1], [Define to 1 on Solaris.])
+      ;;
+  esac
+
+  AC_CACHE_CHECK([whether locale.h conforms to POSIX:2001],
+    [gl_cv_header_locale_h_posix2001],
+    [AC_COMPILE_IFELSE(
+       [AC_LANG_PROGRAM(
+          [[#include <locale.h>
+            int x = LC_MESSAGES;
+            int y = sizeof (((struct lconv *) 0)->decimal_point);]],
+          [[]])],
+       [gl_cv_header_locale_h_posix2001=yes],
+       [gl_cv_header_locale_h_posix2001=no])])
+
+  dnl Check whether 'struct lconv' is complete.
+  dnl Bionic libc's 'struct lconv' is just a dummy.
+  dnl On OpenBSD 4.9, HP-UX 11, IRIX 6.5, OSF/1 5.1, Solaris 9, Cygwin 1.5.x,
+  dnl mingw, MSVC 9, it lacks the int_p_* and int_n_* members.
+  AC_CACHE_CHECK([whether struct lconv is properly defined],
+    [gl_cv_sys_struct_lconv_ok],
+    [AC_COMPILE_IFELSE(
+       [AC_LANG_PROGRAM(
+          [[#include <locale.h>
+            struct lconv l;
+            int x = sizeof (l.decimal_point);
+            int y = sizeof (l.int_p_cs_precedes);]],
+          [[]])],
+       [gl_cv_sys_struct_lconv_ok=yes],
+       [gl_cv_sys_struct_lconv_ok=no])
+    ])
+  if test $gl_cv_sys_struct_lconv_ok = no; then
+    dnl On native Windows with MSVC, merely define these member names as macros.
+    dnl This avoids trouble in C++ mode.
+    case "$host_os" in
+      mingw*)
+        AC_EGREP_CPP([Special], [
+#ifdef _MSC_VER
+ Special
+#endif
+          ],
+          [],
+          [REPLACE_STRUCT_LCONV=1])
+        ;;
+      *) REPLACE_STRUCT_LCONV=1 ;;
+    esac
+  fi
+
+  dnl <locale.h> is always overridden, because of GNULIB_POSIXCHECK.
+  gl_NEXT_HEADERS([locale.h])
+
+  dnl Check for declarations of anything we want to poison if the
+  dnl corresponding gnulib module is not in use.
+  gl_WARN_ON_USE_PREPARE([[#include <locale.h>
+/* Some systems provide declarations in a non-standard header.  */
+#if HAVE_XLOCALE_H
+# include <xlocale.h>
+#endif
+    ]],
+    [setlocale newlocale duplocale freelocale])
+])
+
+dnl Checks to determine whether the system has the locale_t type,
+dnl and how to obtain it.
+AC_DEFUN([gl_LOCALE_T],
+[
+  dnl Persuade glibc and Solaris <locale.h> to define locale_t.
+  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+
+  dnl Check whether use of locale_t requires inclusion of <xlocale.h>,
+  dnl e.g. on Mac OS X 10.5. If <locale.h> does not define locale_t by
+  dnl itself, we assume that <xlocale.h> will do so.
+  AC_CACHE_CHECK([whether locale.h defines locale_t],
+    [gl_cv_header_locale_has_locale_t],
+    [AC_COMPILE_IFELSE(
+       [AC_LANG_PROGRAM(
+          [[#include <locale.h>
+            locale_t x;]],
+          [[]])],
+       [gl_cv_header_locale_has_locale_t=yes],
+       [gl_cv_header_locale_has_locale_t=no])
+    ])
+
+  dnl Check for <xlocale.h>.
+  AC_CHECK_HEADERS_ONCE([xlocale.h])
+  if test $ac_cv_header_xlocale_h = yes; then
+    HAVE_XLOCALE_H=1
+    if test $gl_cv_header_locale_has_locale_t = yes; then
+      gl_cv_header_locale_h_needs_xlocale_h=no
+    else
+      gl_cv_header_locale_h_needs_xlocale_h=yes
+    fi
+    HAVE_LOCALE_T=1
+  else
+    HAVE_XLOCALE_H=0
+    gl_cv_header_locale_h_needs_xlocale_h=no
+    if test $gl_cv_header_locale_has_locale_t = yes; then
+      HAVE_LOCALE_T=1
+    else
+      HAVE_LOCALE_T=0
+    fi
+  fi
+  AC_SUBST([HAVE_XLOCALE_H])
+])
+
+AC_DEFUN([gl_LOCALE_MODULE_INDICATOR],
+[
+  dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
+  AC_REQUIRE([gl_LOCALE_H_DEFAULTS])
+  gl_MODULE_INDICATOR_SET_VARIABLE([$1])
+  dnl Define it also as a C macro, for the benefit of the unit tests.
+  gl_MODULE_INDICATOR_FOR_TESTS([$1])
+])
+
+AC_DEFUN([gl_LOCALE_H_DEFAULTS],
+[
+  GNULIB_LOCALECONV=0;     AC_SUBST([GNULIB_LOCALECONV])
+  GNULIB_SETLOCALE=0;      AC_SUBST([GNULIB_SETLOCALE])
+  GNULIB_SETLOCALE_NULL=0; AC_SUBST([GNULIB_SETLOCALE_NULL])
+  GNULIB_DUPLOCALE=0;      AC_SUBST([GNULIB_DUPLOCALE])
+  GNULIB_LOCALENAME=0;     AC_SUBST([GNULIB_LOCALENAME])
+  dnl Assume proper GNU behavior unless another module says otherwise.
+  HAVE_NEWLOCALE=1;       AC_SUBST([HAVE_NEWLOCALE])
+  HAVE_DUPLOCALE=1;       AC_SUBST([HAVE_DUPLOCALE])
+  HAVE_FREELOCALE=1;      AC_SUBST([HAVE_FREELOCALE])
+  REPLACE_LOCALECONV=0;   AC_SUBST([REPLACE_LOCALECONV])
+  REPLACE_SETLOCALE=0;    AC_SUBST([REPLACE_SETLOCALE])
+  REPLACE_NEWLOCALE=0;    AC_SUBST([REPLACE_NEWLOCALE])
+  REPLACE_DUPLOCALE=0;    AC_SUBST([REPLACE_DUPLOCALE])
+  REPLACE_FREELOCALE=0;   AC_SUBST([REPLACE_FREELOCALE])
+  REPLACE_STRUCT_LCONV=0; AC_SUBST([REPLACE_STRUCT_LCONV])
+])
diff --git a/m4/localeconv.m4 b/m4/localeconv.m4
new file mode 100644
index 0000000..a926224
--- /dev/null
+++ b/m4/localeconv.m4
@@ -0,0 +1,22 @@
+# localeconv.m4 serial 1
+dnl Copyright (C) 2012-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_LOCALECONV],
+[
+  AC_REQUIRE([gl_LOCALE_H_DEFAULTS])
+  AC_REQUIRE([gl_LOCALE_H])
+
+  if test $REPLACE_STRUCT_LCONV = 1; then
+    REPLACE_LOCALECONV=1
+  fi
+])
+
+# Prerequisites of lib/localeconv.c.
+AC_DEFUN([gl_PREREQ_LOCALECONV],
+[
+  AC_CHECK_MEMBERS([struct lconv.decimal_point], [], [],
+    [[#include <locale.h>]])
+])
diff --git a/m4/lock.m4 b/m4/lock.m4
new file mode 100644
index 0000000..1c39591
--- /dev/null
+++ b/m4/lock.m4
@@ -0,0 +1,47 @@
+# lock.m4 serial 14
+dnl Copyright (C) 2005-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl From Bruno Haible.
+
+AC_DEFUN([gl_LOCK],
+[
+  AC_REQUIRE([gl_THREADLIB])
+  if test "$gl_threads_api" = posix; then
+    # OSF/1 4.0 and Mac OS X 10.1 lack the pthread_rwlock_t type and the
+    # pthread_rwlock_* functions.
+    has_rwlock=false
+    AC_CHECK_TYPE([pthread_rwlock_t],
+      [has_rwlock=true
+       AC_DEFINE([HAVE_PTHREAD_RWLOCK], [1],
+         [Define if the POSIX multithreading library has read/write locks.])],
+      [],
+      [#include <pthread.h>])
+    if $has_rwlock; then
+      gl_PTHREAD_RWLOCK_RDLOCK_PREFER_WRITER
+    fi
+    # glibc defines PTHREAD_MUTEX_RECURSIVE as enum, not as a macro.
+    AC_COMPILE_IFELSE([
+      AC_LANG_PROGRAM(
+        [[#include <pthread.h>]],
+        [[
+#if __FreeBSD__ == 4
+error "No, in FreeBSD 4.0 recursive mutexes actually don't work."
+#elif (defined __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ \
+       && __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ < 1070)
+error "No, in Mac OS X < 10.7 recursive mutexes actually don't work."
+#else
+int x = (int)PTHREAD_MUTEX_RECURSIVE;
+return !x;
+#endif
+        ]])],
+      [AC_DEFINE([HAVE_PTHREAD_MUTEX_RECURSIVE], [1],
+         [Define if the <pthread.h> defines PTHREAD_MUTEX_RECURSIVE.])])
+  fi
+  gl_PREREQ_LOCK
+])
+
+# Prerequisites of lib/glthread/lock.c.
+AC_DEFUN([gl_PREREQ_LOCK], [:])
diff --git a/m4/lseek.m4 b/m4/lseek.m4
new file mode 100644
index 0000000..472a1cb
--- /dev/null
+++ b/m4/lseek.m4
@@ -0,0 +1,72 @@
+# lseek.m4 serial 11
+dnl Copyright (C) 2007, 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_LSEEK],
+[
+  AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
+
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  AC_REQUIRE([AC_PROG_CC])
+  AC_CHECK_HEADERS_ONCE([unistd.h])
+  AC_CACHE_CHECK([whether lseek detects pipes], [gl_cv_func_lseek_pipe],
+    [case "$host_os" in
+       mingw*)
+         dnl Native Windows.
+         dnl The result of lseek (fd, (off_t)0, SEEK_CUR) or
+         dnl SetFilePointer(handle, 0, NULL, FILE_CURRENT)
+         dnl for a pipe depends on the environment: In a Cygwin 1.5
+         dnl environment it succeeds (wrong); in a Cygwin 1.7 environment
+         dnl it fails with a wrong errno value.
+         gl_cv_func_lseek_pipe=no
+         ;;
+       *)
+         if test $cross_compiling = no; then
+           AC_LINK_IFELSE([AC_LANG_PROGRAM([[
+#include <sys/types.h> /* for off_t */
+#include <stdio.h> /* for SEEK_CUR */
+#if HAVE_UNISTD_H
+# include <unistd.h>
+#else /* on Windows with MSVC */
+# include <io.h>
+#endif
+]GL_MDA_DEFINES],
+[[
+  /* Exit with success only if stdin is seekable.  */
+  return lseek (0, (off_t)0, SEEK_CUR) < 0;
+]])],
+             [if test -s conftest$ac_exeext \
+                 && ./conftest$ac_exeext < conftest.$ac_ext \
+                 && test 1 = "`echo hi \
+                   | { ./conftest$ac_exeext; echo $?; cat >/dev/null; }`"; then
+                gl_cv_func_lseek_pipe=yes
+              else
+                gl_cv_func_lseek_pipe=no
+              fi
+             ],
+             [gl_cv_func_lseek_pipe=no])
+         else
+           AC_COMPILE_IFELSE(
+             [AC_LANG_SOURCE([[
+#if defined __BEOS__
+/* BeOS mistakenly return 0 when trying to seek on pipes.  */
+  Choke me.
+#endif]])],
+             [gl_cv_func_lseek_pipe=yes], [gl_cv_func_lseek_pipe=no])
+         fi
+         ;;
+     esac
+    ])
+  if test $gl_cv_func_lseek_pipe = no; then
+    REPLACE_LSEEK=1
+    AC_DEFINE([LSEEK_PIPE_BROKEN], [1],
+      [Define to 1 if lseek does not detect pipes.])
+  fi
+
+  AC_REQUIRE([gl_SYS_TYPES_H])
+  if test $WINDOWS_64_BIT_OFF_T = 1; then
+    REPLACE_LSEEK=1
+  fi
+])
diff --git a/m4/lstat.m4 b/m4/lstat.m4
new file mode 100644
index 0000000..3c2b214
--- /dev/null
+++ b/m4/lstat.m4
@@ -0,0 +1,79 @@
+# serial 33
+
+# Copyright (C) 1997-2001, 2003-2020 Free Software Foundation, Inc.
+#
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+dnl From Jim Meyering.
+
+AC_DEFUN([gl_FUNC_LSTAT],
+[
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  AC_REQUIRE([gl_SYS_STAT_H_DEFAULTS])
+  dnl If lstat does not exist, the replacement <sys/stat.h> does
+  dnl "#define lstat stat", and lstat.c is a no-op.
+  AC_CHECK_FUNCS_ONCE([lstat])
+  if test $ac_cv_func_lstat = yes; then
+    AC_REQUIRE([gl_FUNC_LSTAT_FOLLOWS_SLASHED_SYMLINK])
+    case $host_os,$gl_cv_func_lstat_dereferences_slashed_symlink in
+      solaris* | *no)
+        REPLACE_LSTAT=1
+        ;;
+    esac
+  else
+    HAVE_LSTAT=0
+  fi
+])
+
+# Prerequisites of lib/lstat.c.
+AC_DEFUN([gl_PREREQ_LSTAT], [:])
+
+AC_DEFUN([gl_FUNC_LSTAT_FOLLOWS_SLASHED_SYMLINK],
+[
+  dnl We don't use AC_FUNC_LSTAT_FOLLOWS_SLASHED_SYMLINK any more, because it
+  dnl is no longer maintained in Autoconf and because it invokes AC_LIBOBJ.
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_CACHE_CHECK([whether lstat correctly handles trailing slash],
+    [gl_cv_func_lstat_dereferences_slashed_symlink],
+    [rm -f conftest.sym conftest.file
+     echo >conftest.file
+     AC_RUN_IFELSE(
+       [AC_LANG_PROGRAM(
+          [AC_INCLUDES_DEFAULT],
+          [[struct stat sbuf;
+            if (symlink ("conftest.file", "conftest.sym") != 0)
+              return 1;
+            /* Linux will dereference the symlink and fail, as required by
+               POSIX.  That is better in the sense that it means we will not
+               have to compile and use the lstat wrapper.  */
+            return lstat ("conftest.sym/", &sbuf) == 0;
+          ]])],
+       [gl_cv_func_lstat_dereferences_slashed_symlink=yes],
+       [gl_cv_func_lstat_dereferences_slashed_symlink=no],
+       [case "$host_os" in
+          linux-* | linux)
+            # Guess yes on Linux systems.
+            gl_cv_func_lstat_dereferences_slashed_symlink="guessing yes" ;;
+          *-gnu* | gnu*)
+            # Guess yes on glibc systems.
+            gl_cv_func_lstat_dereferences_slashed_symlink="guessing yes" ;;
+          mingw*)
+            # Guess no on native Windows.
+            gl_cv_func_lstat_dereferences_slashed_symlink="guessing no" ;;
+          *)
+            # If we don't know, obey --enable-cross-guesses.
+            gl_cv_func_lstat_dereferences_slashed_symlink="$gl_cross_guess_normal" ;;
+        esac
+       ])
+     rm -f conftest.sym conftest.file
+    ])
+  case "$gl_cv_func_lstat_dereferences_slashed_symlink" in
+    *yes)
+      AC_DEFINE_UNQUOTED([LSTAT_FOLLOWS_SLASHED_SYMLINK], [1],
+        [Define to 1 if 'lstat' dereferences a symlink specified
+         with a trailing slash.])
+      ;;
+  esac
+])
diff --git a/m4/malloc.m4 b/m4/malloc.m4
new file mode 100644
index 0000000..3823566
--- /dev/null
+++ b/m4/malloc.m4
@@ -0,0 +1,98 @@
+# malloc.m4 serial 21
+dnl Copyright (C) 2007, 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+# This is adapted with modifications from upstream Autoconf here:
+# https://git.savannah.gnu.org/cgit/autoconf.git/commit/?id=04be2b7a29d65d9a08e64e8e56e594c91749598c
+AC_DEFUN([_AC_FUNC_MALLOC_IF],
+[
+  AC_REQUIRE([AC_CANONICAL_HOST])dnl for cross-compiles
+  AC_CACHE_CHECK([for GNU libc compatible malloc],
+    [ac_cv_func_malloc_0_nonnull],
+    [AC_RUN_IFELSE(
+       [AC_LANG_PROGRAM(
+          [[#include <stdlib.h>
+          ]],
+          [[char *p = malloc (0);
+            int result = !p;
+            free (p);
+            return result;]])
+       ],
+       [ac_cv_func_malloc_0_nonnull=yes],
+       [ac_cv_func_malloc_0_nonnull=no],
+       [case "$host_os" in
+          # Guess yes on platforms where we know the result.
+          *-gnu* | gnu* | *-musl* | freebsd* | netbsd* | openbsd* \
+          | hpux* | solaris* | cygwin* | mingw*)
+            ac_cv_func_malloc_0_nonnull="guessing yes" ;;
+          # If we don't know, obey --enable-cross-guesses.
+          *) ac_cv_func_malloc_0_nonnull="$gl_cross_guess_normal" ;;
+        esac
+       ])
+    ])
+  case "$ac_cv_func_malloc_0_nonnull" in
+    *yes)
+      $1
+      ;;
+    *)
+      $2
+      ;;
+  esac
+])# _AC_FUNC_MALLOC_IF
+
+# gl_FUNC_MALLOC_GNU
+# ------------------
+# Test whether 'malloc (0)' is handled like in GNU libc, and replace malloc if
+# it is not.
+AC_DEFUN([gl_FUNC_MALLOC_GNU],
+[
+  AC_REQUIRE([gl_STDLIB_H_DEFAULTS])
+  dnl _AC_FUNC_MALLOC_IF is defined in Autoconf.
+  _AC_FUNC_MALLOC_IF(
+    [AC_DEFINE([HAVE_MALLOC_GNU], [1],
+               [Define to 1 if your system has a GNU libc compatible 'malloc'
+                function, and to 0 otherwise.])],
+    [AC_DEFINE([HAVE_MALLOC_GNU], [0])
+     REPLACE_MALLOC=1
+    ])
+])
+
+# gl_FUNC_MALLOC_POSIX
+# --------------------
+# Test whether 'malloc' is POSIX compliant (sets errno to ENOMEM when it
+# fails), and replace malloc if it is not.
+AC_DEFUN([gl_FUNC_MALLOC_POSIX],
+[
+  AC_REQUIRE([gl_STDLIB_H_DEFAULTS])
+  AC_REQUIRE([gl_CHECK_MALLOC_POSIX])
+  if test $gl_cv_func_malloc_posix = yes; then
+    AC_DEFINE([HAVE_MALLOC_POSIX], [1],
+      [Define if the 'malloc' function is POSIX compliant.])
+  else
+    REPLACE_MALLOC=1
+  fi
+])
+
+# Test whether malloc, realloc, calloc are POSIX compliant,
+# Set gl_cv_func_malloc_posix to yes or no accordingly.
+AC_DEFUN([gl_CHECK_MALLOC_POSIX],
+[
+  AC_CACHE_CHECK([whether malloc, realloc, calloc are POSIX compliant],
+    [gl_cv_func_malloc_posix],
+    [
+      dnl It is too dangerous to try to allocate a large amount of memory:
+      dnl some systems go to their knees when you do that. So assume that
+      dnl all Unix implementations of the function are POSIX compliant.
+      AC_COMPILE_IFELSE(
+        [AC_LANG_PROGRAM(
+           [[]],
+           [[#if defined _WIN32 && ! defined __CYGWIN__
+             choke me
+             #endif
+            ]])],
+        [gl_cv_func_malloc_posix=yes],
+        [gl_cv_func_malloc_posix=no])
+    ])
+])
diff --git a/m4/malloca.m4 b/m4/malloca.m4
new file mode 100644
index 0000000..930199d
--- /dev/null
+++ b/m4/malloca.m4
@@ -0,0 +1,14 @@
+# malloca.m4 serial 2
+dnl Copyright (C) 2003-2004, 2006-2007, 2009-2020 Free Software Foundation,
+dnl Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_MALLOCA],
+[
+  dnl Use the autoconf tests for alloca(), but not the AC_SUBSTed variables
+  dnl @ALLOCA@ and @LTALLOCA@.
+  dnl gl_FUNC_ALLOCA   dnl Already brought in by the module dependencies.
+  AC_REQUIRE([gl_EEMALLOC])
+])
diff --git a/m4/mbchar.m4 b/m4/mbchar.m4
new file mode 100644
index 0000000..5e3efa6
--- /dev/null
+++ b/m4/mbchar.m4
@@ -0,0 +1,13 @@
+# mbchar.m4 serial 9
+dnl Copyright (C) 2005-2007, 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl autoconf tests required for use of mbchar.m4
+dnl From Bruno Haible.
+
+AC_DEFUN([gl_MBCHAR],
+[
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
+])
diff --git a/m4/mbiter.m4 b/m4/mbiter.m4
new file mode 100644
index 0000000..e6b49a9
--- /dev/null
+++ b/m4/mbiter.m4
@@ -0,0 +1,14 @@
+# mbiter.m4 serial 7
+dnl Copyright (C) 2005, 2008-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl autoconf tests required for use of mbiter.h
+dnl From Bruno Haible.
+
+AC_DEFUN([gl_MBITER],
+[
+  AC_REQUIRE([AC_TYPE_MBSTATE_T])
+  :
+])
diff --git a/m4/mbrtowc.m4 b/m4/mbrtowc.m4
new file mode 100644
index 0000000..ad31a7b
--- /dev/null
+++ b/m4/mbrtowc.m4
@@ -0,0 +1,790 @@
+# mbrtowc.m4 serial 38  -*- coding: utf-8 -*-
+dnl Copyright (C) 2001-2002, 2004-2005, 2008-2020 Free Software Foundation,
+dnl Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_MBRTOWC],
+[
+  AC_REQUIRE([gl_WCHAR_H_DEFAULTS])
+  AC_REQUIRE([gl_PTHREADLIB])
+  AC_CHECK_HEADERS_ONCE([threads.h])
+
+  AC_REQUIRE([AC_TYPE_MBSTATE_T])
+  gl_MBSTATE_T_BROKEN
+
+  AC_CHECK_FUNCS_ONCE([mbrtowc])
+  if test $ac_cv_func_mbrtowc = no; then
+    HAVE_MBRTOWC=0
+    AC_CHECK_DECLS([mbrtowc],,, [[
+      #include <wchar.h>
+    ]])
+    if test $ac_cv_have_decl_mbrtowc = yes; then
+      dnl On Minix 3.1.8, the system's <wchar.h> declares mbrtowc() although
+      dnl it does not have the function. Avoid a collision with gnulib's
+      dnl replacement.
+      REPLACE_MBRTOWC=1
+    fi
+  else
+    if test $REPLACE_MBSTATE_T = 1; then
+      REPLACE_MBRTOWC=1
+    else
+      gl_MBRTOWC_NULL_ARG1
+      gl_MBRTOWC_NULL_ARG2
+      gl_MBRTOWC_RETVAL
+      gl_MBRTOWC_NUL_RETVAL
+      gl_MBRTOWC_STORES_INCOMPLETE
+      gl_MBRTOWC_EMPTY_INPUT
+      gl_MBRTOWC_C_LOCALE
+      case "$gl_cv_func_mbrtowc_null_arg1" in
+        *yes) ;;
+        *) AC_DEFINE([MBRTOWC_NULL_ARG1_BUG], [1],
+             [Define if the mbrtowc function has the NULL pwc argument bug.])
+           REPLACE_MBRTOWC=1
+           ;;
+      esac
+      case "$gl_cv_func_mbrtowc_null_arg2" in
+        *yes) ;;
+        *) AC_DEFINE([MBRTOWC_NULL_ARG2_BUG], [1],
+             [Define if the mbrtowc function has the NULL string argument bug.])
+           REPLACE_MBRTOWC=1
+           ;;
+      esac
+      case "$gl_cv_func_mbrtowc_retval" in
+        *yes) ;;
+        *) AC_DEFINE([MBRTOWC_RETVAL_BUG], [1],
+             [Define if the mbrtowc function returns a wrong return value.])
+           REPLACE_MBRTOWC=1
+           ;;
+      esac
+      case "$gl_cv_func_mbrtowc_nul_retval" in
+        *yes) ;;
+        *) AC_DEFINE([MBRTOWC_NUL_RETVAL_BUG], [1],
+             [Define if the mbrtowc function does not return 0 for a NUL character.])
+           REPLACE_MBRTOWC=1
+           ;;
+      esac
+      case "$gl_cv_func_mbrtowc_stores_incomplete" in
+        *no) ;;
+        *) AC_DEFINE([MBRTOWC_STORES_INCOMPLETE_BUG], [1],
+             [Define if the mbrtowc function stores a wide character when reporting incomplete input.])
+           REPLACE_MBRTOWC=1
+           ;;
+      esac
+      case "$gl_cv_func_mbrtowc_empty_input" in
+        *yes) ;;
+        *) AC_DEFINE([MBRTOWC_EMPTY_INPUT_BUG], [1],
+             [Define if the mbrtowc function does not return (size_t) -2
+              for empty input.])
+           REPLACE_MBRTOWC=1
+           ;;
+      esac
+      case "$gl_cv_func_mbrtowc_C_locale_sans_EILSEQ" in
+        *yes) ;;
+        *) AC_DEFINE([MBRTOWC_IN_C_LOCALE_MAYBE_EILSEQ], [1],
+             [Define if the mbrtowc function may signal encoding errors in the C locale.])
+           REPLACE_MBRTOWC=1
+           ;;
+      esac
+    fi
+  fi
+  if test $REPLACE_MBSTATE_T = 1; then
+    case "$host_os" in
+      mingw*) LIB_MBRTOWC= ;;
+      *)
+        gl_WEAK_SYMBOLS
+        case "$gl_cv_have_weak" in
+          *yes) LIB_MBRTOWC= ;;
+          *)    LIB_MBRTOWC="$LIBPTHREAD" ;;
+        esac
+        ;;
+    esac
+  else
+    LIB_MBRTOWC=
+  fi
+  dnl LIB_MBRTOWC is expected to be '-pthread' or '-lpthread' on AIX
+  dnl with gcc or xlc, and empty otherwise.
+  AC_SUBST([LIB_MBRTOWC])
+])
+
+dnl Test whether mbsinit() and mbrtowc() need to be overridden in a way that
+dnl redefines the semantics of the given mbstate_t type.
+dnl Result is REPLACE_MBSTATE_T.
+dnl When this is set to 1, we replace both mbsinit() and mbrtowc(), in order to
+dnl avoid inconsistencies.
+
+AC_DEFUN([gl_MBSTATE_T_BROKEN],
+[
+  AC_REQUIRE([gl_WCHAR_H_DEFAULTS])
+  AC_REQUIRE([AC_CANONICAL_HOST])
+
+  AC_REQUIRE([AC_TYPE_MBSTATE_T])
+  AC_CHECK_FUNCS_ONCE([mbsinit])
+  AC_CHECK_FUNCS_ONCE([mbrtowc])
+  dnl On native Windows, we know exactly how mbsinit() behaves and don't need
+  dnl to override it, even if - like on MSVC - mbsinit() is only defined as
+  dnl an inline function, not as a global function.
+  if case "$host_os" in
+       mingw*) true ;;
+       *) test $ac_cv_func_mbsinit = yes ;;
+     esac \
+    && test $ac_cv_func_mbrtowc = yes; then
+    gl_MBRTOWC_INCOMPLETE_STATE
+    gl_MBRTOWC_SANITYCHECK
+    REPLACE_MBSTATE_T=0
+    case "$gl_cv_func_mbrtowc_incomplete_state" in
+      *yes) ;;
+      *) REPLACE_MBSTATE_T=1 ;;
+    esac
+    case "$gl_cv_func_mbrtowc_sanitycheck" in
+      *yes) ;;
+      *) REPLACE_MBSTATE_T=1 ;;
+    esac
+  else
+    REPLACE_MBSTATE_T=1
+  fi
+])
+
+dnl Test whether mbrtowc puts the state into non-initial state when parsing an
+dnl incomplete multibyte character.
+dnl Result is gl_cv_func_mbrtowc_incomplete_state.
+
+AC_DEFUN([gl_MBRTOWC_INCOMPLETE_STATE],
+[
+  AC_REQUIRE([AC_PROG_CC])
+  AC_REQUIRE([gt_LOCALE_JA])
+  AC_REQUIRE([gt_LOCALE_FR_UTF8])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_CACHE_CHECK([whether mbrtowc handles incomplete characters],
+    [gl_cv_func_mbrtowc_incomplete_state],
+    [
+      dnl Initial guess, used when cross-compiling or when no suitable locale
+      dnl is present.
+changequote(,)dnl
+      case "$host_os" in
+                     # Guess no on AIX and OSF/1.
+        aix* | osf*) gl_cv_func_mbrtowc_incomplete_state="guessing no" ;;
+                     # Guess yes otherwise.
+        *)           gl_cv_func_mbrtowc_incomplete_state="guessing yes" ;;
+      esac
+changequote([,])dnl
+      if test $LOCALE_JA != none; then
+        AC_RUN_IFELSE(
+          [AC_LANG_SOURCE([[
+#include <locale.h>
+#include <string.h>
+#include <wchar.h>
+int main ()
+{
+  if (setlocale (LC_ALL, "$LOCALE_JA") != NULL)
+    {
+      const char input[] = "B\217\253\344\217\251\316er"; /* "Büßer" */
+      mbstate_t state;
+      wchar_t wc;
+
+      memset (&state, '\0', sizeof (mbstate_t));
+      if (mbrtowc (&wc, input + 1, 1, &state) == (size_t)(-2))
+        if (mbsinit (&state))
+          return 2;
+    }
+  return 0;
+}]])],
+          [gl_cv_func_mbrtowc_incomplete_state=yes],
+          [gl_cv_func_mbrtowc_incomplete_state=no],
+          [:])
+      else
+        if test $LOCALE_FR_UTF8 != none; then
+          AC_RUN_IFELSE(
+            [AC_LANG_SOURCE([[
+#include <locale.h>
+#include <string.h>
+#include <wchar.h>
+int main ()
+{
+  if (setlocale (LC_ALL, "$LOCALE_FR_UTF8") != NULL)
+    {
+      const char input[] = "B\303\274\303\237er"; /* "Büßer" */
+      mbstate_t state;
+      wchar_t wc;
+
+      memset (&state, '\0', sizeof (mbstate_t));
+      if (mbrtowc (&wc, input + 1, 1, &state) == (size_t)(-2))
+        if (mbsinit (&state))
+          return 2;
+    }
+  return 0;
+}]])],
+          [gl_cv_func_mbrtowc_incomplete_state=yes],
+          [gl_cv_func_mbrtowc_incomplete_state=no],
+          [:])
+        fi
+      fi
+    ])
+])
+
+dnl Test whether mbrtowc works not worse than mbtowc.
+dnl Result is gl_cv_func_mbrtowc_sanitycheck.
+
+AC_DEFUN([gl_MBRTOWC_SANITYCHECK],
+[
+  AC_REQUIRE([AC_PROG_CC])
+  AC_REQUIRE([gt_LOCALE_ZH_CN])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_CACHE_CHECK([whether mbrtowc works as well as mbtowc],
+    [gl_cv_func_mbrtowc_sanitycheck],
+    [
+      dnl Initial guess, used when cross-compiling or when no suitable locale
+      dnl is present.
+changequote(,)dnl
+      case "$host_os" in
+                    # Guess no on Solaris 8.
+        solaris2.8) gl_cv_func_mbrtowc_sanitycheck="guessing no" ;;
+                    # Guess yes otherwise.
+        *)          gl_cv_func_mbrtowc_sanitycheck="guessing yes" ;;
+      esac
+changequote([,])dnl
+      if test $LOCALE_ZH_CN != none; then
+        AC_RUN_IFELSE(
+          [AC_LANG_SOURCE([[
+#include <locale.h>
+#include <stdlib.h>
+#include <string.h>
+#include <wchar.h>
+int main ()
+{
+  /* This fails on Solaris 8:
+     mbrtowc returns 2, and sets wc to 0x00F0.
+     mbtowc returns 4 (correct) and sets wc to 0x5EDC.  */
+  if (setlocale (LC_ALL, "$LOCALE_ZH_CN") != NULL)
+    {
+      char input[] = "B\250\271\201\060\211\070er"; /* "Büßer" */
+      mbstate_t state;
+      wchar_t wc;
+
+      memset (&state, '\0', sizeof (mbstate_t));
+      if (mbrtowc (&wc, input + 3, 6, &state) != 4
+          && mbtowc (&wc, input + 3, 6) == 4)
+        return 2;
+    }
+  return 0;
+}]])],
+          [gl_cv_func_mbrtowc_sanitycheck=yes],
+          [gl_cv_func_mbrtowc_sanitycheck=no],
+          [:])
+      fi
+    ])
+])
+
+dnl Test whether mbrtowc supports a NULL pwc argument correctly.
+dnl Result is gl_cv_func_mbrtowc_null_arg1.
+
+AC_DEFUN([gl_MBRTOWC_NULL_ARG1],
+[
+  AC_REQUIRE([AC_PROG_CC])
+  AC_REQUIRE([gt_LOCALE_FR_UTF8])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_CACHE_CHECK([whether mbrtowc handles a NULL pwc argument],
+    [gl_cv_func_mbrtowc_null_arg1],
+    [
+      dnl Initial guess, used when cross-compiling or when no suitable locale
+      dnl is present.
+changequote(,)dnl
+      case "$host_os" in
+                  # Guess no on Solaris.
+        solaris*) gl_cv_func_mbrtowc_null_arg1="guessing no" ;;
+                  # Guess yes otherwise.
+        *)        gl_cv_func_mbrtowc_null_arg1="guessing yes" ;;
+      esac
+changequote([,])dnl
+      if test $LOCALE_FR_UTF8 != none; then
+        AC_RUN_IFELSE(
+          [AC_LANG_SOURCE([[
+#include <locale.h>
+#include <stdlib.h>
+#include <string.h>
+#include <wchar.h>
+int main ()
+{
+  int result = 0;
+
+  if (setlocale (LC_ALL, "$LOCALE_FR_UTF8") != NULL)
+    {
+      char input[] = "\303\237er";
+      mbstate_t state;
+      wchar_t wc;
+      size_t ret;
+
+      memset (&state, '\0', sizeof (mbstate_t));
+      wc = (wchar_t) 0xBADFACE;
+      ret = mbrtowc (&wc, input, 5, &state);
+      if (ret != 2)
+        result |= 1;
+      if (!mbsinit (&state))
+        result |= 2;
+
+      memset (&state, '\0', sizeof (mbstate_t));
+      ret = mbrtowc (NULL, input, 5, &state);
+      if (ret != 2) /* Solaris 7 fails here: ret is -1.  */
+        result |= 4;
+      if (!mbsinit (&state))
+        result |= 8;
+    }
+  return result;
+}]])],
+          [gl_cv_func_mbrtowc_null_arg1=yes],
+          [gl_cv_func_mbrtowc_null_arg1=no],
+          [:])
+      fi
+    ])
+])
+
+dnl Test whether mbrtowc supports a NULL string argument correctly.
+dnl Result is gl_cv_func_mbrtowc_null_arg2.
+
+AC_DEFUN([gl_MBRTOWC_NULL_ARG2],
+[
+  AC_REQUIRE([AC_PROG_CC])
+  AC_REQUIRE([gt_LOCALE_FR_UTF8])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_CACHE_CHECK([whether mbrtowc handles a NULL string argument],
+    [gl_cv_func_mbrtowc_null_arg2],
+    [
+      dnl Initial guess, used when cross-compiling or when no suitable locale
+      dnl is present.
+changequote(,)dnl
+      case "$host_os" in
+              # Guess no on OSF/1.
+        osf*) gl_cv_func_mbrtowc_null_arg2="guessing no" ;;
+              # Guess yes otherwise.
+        *)    gl_cv_func_mbrtowc_null_arg2="guessing yes" ;;
+      esac
+changequote([,])dnl
+      if test $LOCALE_FR_UTF8 != none; then
+        AC_RUN_IFELSE(
+          [AC_LANG_SOURCE([[
+#include <locale.h>
+#include <string.h>
+#include <wchar.h>
+int main ()
+{
+  if (setlocale (LC_ALL, "$LOCALE_FR_UTF8") != NULL)
+    {
+      mbstate_t state;
+      wchar_t wc;
+      int ret;
+
+      memset (&state, '\0', sizeof (mbstate_t));
+      wc = (wchar_t) 0xBADFACE;
+      mbrtowc (&wc, NULL, 5, &state);
+      /* Check that wc was not modified.  */
+      if (wc != (wchar_t) 0xBADFACE)
+        return 2;
+    }
+  return 0;
+}]])],
+          [gl_cv_func_mbrtowc_null_arg2=yes],
+          [gl_cv_func_mbrtowc_null_arg2=no],
+          [:])
+      fi
+    ])
+])
+
+dnl Test whether mbrtowc, when parsing the end of a multibyte character,
+dnl correctly returns the number of bytes that were needed to complete the
+dnl character (not the total number of bytes of the multibyte character).
+dnl Result is gl_cv_func_mbrtowc_retval.
+
+AC_DEFUN([gl_MBRTOWC_RETVAL],
+[
+  AC_REQUIRE([AC_PROG_CC])
+  AC_REQUIRE([gt_LOCALE_FR_UTF8])
+  AC_REQUIRE([gt_LOCALE_JA])
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  AC_CACHE_CHECK([whether mbrtowc has a correct return value],
+    [gl_cv_func_mbrtowc_retval],
+    [
+      dnl Initial guess, used when cross-compiling or when no suitable locale
+      dnl is present.
+changequote(,)dnl
+      case "$host_os" in
+                                   # Guess no on HP-UX, Solaris, native Windows.
+        hpux* | solaris* | mingw*) gl_cv_func_mbrtowc_retval="guessing no" ;;
+                                   # Guess yes otherwise.
+        *)                         gl_cv_func_mbrtowc_retval="guessing yes" ;;
+      esac
+changequote([,])dnl
+      if test $LOCALE_FR_UTF8 != none || test $LOCALE_JA != none \
+         || { case "$host_os" in mingw*) true;; *) false;; esac; }; then
+        AC_RUN_IFELSE(
+          [AC_LANG_SOURCE([[
+#include <locale.h>
+#include <string.h>
+#include <wchar.h>
+int main ()
+{
+  int result = 0;
+  int found_some_locale = 0;
+  /* This fails on Solaris.  */
+  if (setlocale (LC_ALL, "$LOCALE_FR_UTF8") != NULL)
+    {
+      char input[] = "B\303\274\303\237er"; /* "Büßer" */
+      mbstate_t state;
+      wchar_t wc;
+
+      memset (&state, '\0', sizeof (mbstate_t));
+      if (mbrtowc (&wc, input + 1, 1, &state) == (size_t)(-2))
+        {
+          input[1] = '\0';
+          if (mbrtowc (&wc, input + 2, 5, &state) != 1)
+            result |= 1;
+        }
+      found_some_locale = 1;
+    }
+  /* This fails on HP-UX 11.11.  */
+  if (setlocale (LC_ALL, "$LOCALE_JA") != NULL)
+    {
+      char input[] = "B\217\253\344\217\251\316er"; /* "Büßer" */
+      mbstate_t state;
+      wchar_t wc;
+
+      memset (&state, '\0', sizeof (mbstate_t));
+      if (mbrtowc (&wc, input + 1, 1, &state) == (size_t)(-2))
+        {
+          input[1] = '\0';
+          if (mbrtowc (&wc, input + 2, 5, &state) != 2)
+            result |= 2;
+        }
+      found_some_locale = 1;
+    }
+  /* This fails on native Windows.  */
+  if (setlocale (LC_ALL, "Japanese_Japan.932") != NULL)
+    {
+      char input[] = "<\223\372\226\173\214\352>"; /* "<日本語>" */
+      mbstate_t state;
+      wchar_t wc;
+
+      memset (&state, '\0', sizeof (mbstate_t));
+      if (mbrtowc (&wc, input + 3, 1, &state) == (size_t)(-2))
+        {
+          input[3] = '\0';
+          if (mbrtowc (&wc, input + 4, 4, &state) != 1)
+            result |= 4;
+        }
+      found_some_locale = 1;
+    }
+  if (setlocale (LC_ALL, "Chinese_Taiwan.950") != NULL)
+    {
+      char input[] = "<\244\351\245\273\273\171>"; /* "<日本語>" */
+      mbstate_t state;
+      wchar_t wc;
+
+      memset (&state, '\0', sizeof (mbstate_t));
+      if (mbrtowc (&wc, input + 3, 1, &state) == (size_t)(-2))
+        {
+          input[3] = '\0';
+          if (mbrtowc (&wc, input + 4, 4, &state) != 1)
+            result |= 8;
+        }
+      found_some_locale = 1;
+    }
+  if (setlocale (LC_ALL, "Chinese_China.936") != NULL)
+    {
+      char input[] = "<\310\325\261\276\325\132>"; /* "<日本語>" */
+      mbstate_t state;
+      wchar_t wc;
+
+      memset (&state, '\0', sizeof (mbstate_t));
+      if (mbrtowc (&wc, input + 3, 1, &state) == (size_t)(-2))
+        {
+          input[3] = '\0';
+          if (mbrtowc (&wc, input + 4, 4, &state) != 1)
+            result |= 16;
+        }
+      found_some_locale = 1;
+    }
+  return (found_some_locale ? result : 77);
+}]])],
+          [gl_cv_func_mbrtowc_retval=yes],
+          [if test $? != 77; then
+             gl_cv_func_mbrtowc_retval=no
+           fi
+          ],
+          [:])
+      fi
+    ])
+])
+
+dnl Test whether mbrtowc, when parsing a NUL character, correctly returns 0.
+dnl Result is gl_cv_func_mbrtowc_nul_retval.
+
+AC_DEFUN([gl_MBRTOWC_NUL_RETVAL],
+[
+  AC_REQUIRE([AC_PROG_CC])
+  AC_REQUIRE([gt_LOCALE_ZH_CN])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_CACHE_CHECK([whether mbrtowc returns 0 when parsing a NUL character],
+    [gl_cv_func_mbrtowc_nul_retval],
+    [
+      dnl Initial guess, used when cross-compiling or when no suitable locale
+      dnl is present.
+changequote(,)dnl
+      case "$host_os" in
+                       # Guess no on Solaris 8 and 9.
+        solaris2.[89]) gl_cv_func_mbrtowc_nul_retval="guessing no" ;;
+                       # Guess yes otherwise.
+        *)             gl_cv_func_mbrtowc_nul_retval="guessing yes" ;;
+      esac
+changequote([,])dnl
+      if test $LOCALE_ZH_CN != none; then
+        AC_RUN_IFELSE(
+          [AC_LANG_SOURCE([[
+#include <locale.h>
+#include <string.h>
+#include <wchar.h>
+int main ()
+{
+  /* This fails on Solaris 8 and 9.  */
+  if (setlocale (LC_ALL, "$LOCALE_ZH_CN") != NULL)
+    {
+      mbstate_t state;
+      wchar_t wc;
+
+      memset (&state, '\0', sizeof (mbstate_t));
+      if (mbrtowc (&wc, "", 1, &state) != 0)
+        return 2;
+    }
+  return 0;
+}]])],
+          [gl_cv_func_mbrtowc_nul_retval=yes],
+          [gl_cv_func_mbrtowc_nul_retval=no],
+          [:])
+      fi
+    ])
+])
+
+dnl Test whether mbrtowc stores a wide character when reporting incomplete
+dnl input.
+
+AC_DEFUN([gl_MBRTOWC_STORES_INCOMPLETE],
+[
+  AC_REQUIRE([AC_PROG_CC])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_CACHE_CHECK([whether mbrtowc stores incomplete characters],
+    [gl_cv_func_mbrtowc_stores_incomplete],
+    [
+     dnl Initial guess, used when cross-compiling or when no suitable locale
+     dnl is present.
+changequote(,)dnl
+     case "$host_os" in
+               # Guess yes on native Windows.
+       mingw*) gl_cv_func_mbrtowc_stores_incomplete="guessing yes" ;;
+       *)      gl_cv_func_mbrtowc_stores_incomplete="guessing no" ;;
+     esac
+changequote([,])dnl
+     case "$host_os" in
+       mingw*)
+         AC_RUN_IFELSE(
+           [AC_LANG_SOURCE([[
+#include <locale.h>
+#include <string.h>
+#include <wchar.h>
+int main ()
+{
+  int result = 0;
+  if (setlocale (LC_ALL, "French_France.65001") != NULL)
+    {
+      wchar_t wc = (wchar_t) 0xBADFACE;
+      mbstate_t state;
+
+      memset (&state, '\0', sizeof (mbstate_t));
+      if (mbrtowc (&wc, "\303", 1, &state) == (size_t)(-2)
+          && wc != (wchar_t) 0xBADFACE)
+        result |= 1;
+    }
+  if (setlocale (LC_ALL, "Japanese_Japan.932") != NULL)
+    {
+      wchar_t wc = (wchar_t) 0xBADFACE;
+      mbstate_t state;
+
+      memset (&state, '\0', sizeof (mbstate_t));
+      if (mbrtowc (&wc, "\226", 1, &state) == (size_t)(-2)
+          && wc != (wchar_t) 0xBADFACE)
+        result |= 2;
+    }
+  if (setlocale (LC_ALL, "Chinese_Taiwan.950") != NULL)
+    {
+      wchar_t wc = (wchar_t) 0xBADFACE;
+      mbstate_t state;
+
+      memset (&state, '\0', sizeof (mbstate_t));
+      if (mbrtowc (&wc, "\245", 1, &state) == (size_t)(-2)
+          && wc != (wchar_t) 0xBADFACE)
+        result |= 4;
+    }
+  if (setlocale (LC_ALL, "Chinese_China.936") != NULL)
+    {
+      wchar_t wc = (wchar_t) 0xBADFACE;
+      mbstate_t state;
+
+      memset (&state, '\0', sizeof (mbstate_t));
+      if (mbrtowc (&wc, "\261", 1, &state) == (size_t)(-2)
+          && wc != (wchar_t) 0xBADFACE)
+        result |= 8;
+    }
+  return result;
+}]])],
+           [gl_cv_func_mbrtowc_stores_incomplete=no],
+           [gl_cv_func_mbrtowc_stores_incomplete=yes],
+           [:])
+         ;;
+       *)
+         AC_REQUIRE([gt_LOCALE_FR_UTF8])
+         if test $LOCALE_FR_UTF8 != none; then
+           AC_RUN_IFELSE(
+             [AC_LANG_SOURCE([[
+#include <locale.h>
+#include <string.h>
+#include <wchar.h>
+int main ()
+{
+  if (setlocale (LC_ALL, "$LOCALE_FR_UTF8") != NULL)
+    {
+      wchar_t wc = (wchar_t) 0xBADFACE;
+      mbstate_t state;
+
+      memset (&state, '\0', sizeof (mbstate_t));
+      if (mbrtowc (&wc, "\303", 1, &state) == (size_t)(-2)
+          && wc != (wchar_t) 0xBADFACE)
+        return 1;
+    }
+  return 0;
+}]])],
+             [gl_cv_func_mbrtowc_stores_incomplete=no],
+             [gl_cv_func_mbrtowc_stores_incomplete=yes],
+             [:])
+         fi
+         ;;
+     esac
+    ])
+])
+
+dnl Test whether mbrtowc returns the correct value on empty input.
+
+AC_DEFUN([gl_MBRTOWC_EMPTY_INPUT],
+[
+  AC_REQUIRE([AC_PROG_CC])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_CACHE_CHECK([whether mbrtowc works on empty input],
+    [gl_cv_func_mbrtowc_empty_input],
+    [
+      dnl Initial guess, used when cross-compiling or when no suitable locale
+      dnl is present.
+changequote(,)dnl
+      case "$host_os" in
+                              # Guess no on AIX and glibc systems.
+        aix* | *-gnu* | gnu*) gl_cv_func_mbrtowc_empty_input="guessing no" ;;
+                              # Guess yes on native Windows.
+        mingw*)               gl_cv_func_mbrtowc_empty_input="guessing yes" ;;
+        *)                    gl_cv_func_mbrtowc_empty_input="guessing yes" ;;
+      esac
+changequote([,])dnl
+      AC_RUN_IFELSE(
+        [AC_LANG_SOURCE([[
+           #include <wchar.h>
+           static wchar_t wc;
+           static mbstate_t mbs;
+           int
+           main (void)
+           {
+             return mbrtowc (&wc, "", 0, &mbs) != (size_t) -2;
+           }]])],
+        [gl_cv_func_mbrtowc_empty_input=yes],
+        [gl_cv_func_mbrtowc_empty_input=no],
+        [:])
+    ])
+])
+
+dnl Test whether mbrtowc reports encoding errors in the C locale.
+dnl Although POSIX was never intended to allow this, the GNU C Library
+dnl and other implementations do it.  See:
+dnl https://sourceware.org/bugzilla/show_bug.cgi?id=19932
+
+AC_DEFUN([gl_MBRTOWC_C_LOCALE],
+[
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_CACHE_CHECK([whether the C locale is free of encoding errors],
+    [gl_cv_func_mbrtowc_C_locale_sans_EILSEQ],
+    [
+     dnl Initial guess, used when cross-compiling or when no suitable locale
+     dnl is present.
+     gl_cv_func_mbrtowc_C_locale_sans_EILSEQ="$gl_cross_guess_normal"
+
+     AC_RUN_IFELSE(
+       [AC_LANG_PROGRAM(
+          [[#include <limits.h>
+            #include <locale.h>
+            #include <wchar.h>
+          ]], [[
+            int i;
+            char *locale = setlocale (LC_ALL, "C");
+            if (! locale)
+              return 2;
+            for (i = CHAR_MIN; i <= CHAR_MAX; i++)
+              {
+                char c = i;
+                wchar_t wc;
+                mbstate_t mbs = { 0, };
+                size_t ss = mbrtowc (&wc, &c, 1, &mbs);
+                if (1 < ss)
+                  return 3;
+              }
+            return 0;
+          ]])],
+      [gl_cv_func_mbrtowc_C_locale_sans_EILSEQ=yes],
+      [gl_cv_func_mbrtowc_C_locale_sans_EILSEQ=no],
+      [case "$host_os" in
+                 # Guess yes on native Windows.
+         mingw*) gl_cv_func_mbrtowc_C_locale_sans_EILSEQ="guessing yes" ;;
+       esac
+      ])
+    ])
+])
+
+# Prerequisites of lib/mbrtowc.c and lib/lc-charset-dispatch.c.
+AC_DEFUN([gl_PREREQ_MBRTOWC], [
+  AC_REQUIRE([AC_C_INLINE])
+  :
+])
+
+# Prerequisites of lib/mbtowc-lock.c.
+AC_DEFUN([gl_PREREQ_MBTOWC_LOCK],
+[
+  gl_VISIBILITY
+])
+
+
+dnl From Paul Eggert
+
+dnl This is an override of an autoconf macro.
+
+AC_DEFUN([AC_FUNC_MBRTOWC],
+[
+  dnl Same as AC_FUNC_MBRTOWC in autoconf-2.60.
+  AC_CACHE_CHECK([whether mbrtowc and mbstate_t are properly declared],
+    [gl_cv_func_mbrtowc],
+    [AC_LINK_IFELSE(
+       [AC_LANG_PROGRAM(
+            [[#include <wchar.h>]],
+            [[wchar_t wc;
+              char const s[] = "";
+              size_t n = 1;
+              mbstate_t state;
+              return ! (sizeof state && (mbrtowc) (&wc, s, n, &state));]])],
+       [gl_cv_func_mbrtowc=yes],
+       [gl_cv_func_mbrtowc=no])])
+  if test $gl_cv_func_mbrtowc = yes; then
+    AC_DEFINE([HAVE_MBRTOWC], [1],
+      [Define to 1 if mbrtowc and mbstate_t are properly declared.])
+  fi
+])
diff --git a/m4/mbsinit.m4 b/m4/mbsinit.m4
new file mode 100644
index 0000000..f446659
--- /dev/null
+++ b/m4/mbsinit.m4
@@ -0,0 +1,44 @@
+# mbsinit.m4 serial 9
+dnl Copyright (C) 2008, 2010-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_MBSINIT],
+[
+  AC_REQUIRE([gl_WCHAR_H_DEFAULTS])
+  AC_REQUIRE([AC_CANONICAL_HOST])
+
+  AC_REQUIRE([AC_TYPE_MBSTATE_T])
+  gl_MBSTATE_T_BROKEN
+
+  AC_CHECK_FUNCS_ONCE([mbsinit])
+  if test $ac_cv_func_mbsinit = no; then
+    HAVE_MBSINIT=0
+    AC_CHECK_DECLS([mbsinit],,, [[
+      #include <wchar.h>
+    ]])
+    if test $ac_cv_have_decl_mbsinit = yes; then
+      dnl On Minix 3.1.8, the system's <wchar.h> declares mbsinit() although
+      dnl it does not have the function. Avoid a collision with gnulib's
+      dnl replacement.
+      REPLACE_MBSINIT=1
+    fi
+  else
+    if test $REPLACE_MBSTATE_T = 1; then
+      REPLACE_MBSINIT=1
+    else
+      dnl On mingw, mbsinit() always returns 1, which is inappropriate for
+      dnl states produced by mbrtowc() for an incomplete multibyte character
+      dnl in multibyte locales.
+      case "$host_os" in
+        mingw*) REPLACE_MBSINIT=1 ;;
+      esac
+    fi
+  fi
+])
+
+# Prerequisites of lib/mbsinit.c.
+AC_DEFUN([gl_PREREQ_MBSINIT], [
+  :
+])
diff --git a/m4/mbsrtowcs.m4 b/m4/mbsrtowcs.m4
new file mode 100644
index 0000000..5a558c3
--- /dev/null
+++ b/m4/mbsrtowcs.m4
@@ -0,0 +1,141 @@
+# mbsrtowcs.m4 serial 14
+dnl Copyright (C) 2008-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_MBSRTOWCS],
+[
+  AC_REQUIRE([gl_WCHAR_H_DEFAULTS])
+
+  AC_REQUIRE([AC_TYPE_MBSTATE_T])
+  gl_MBSTATE_T_BROKEN
+
+  AC_CHECK_FUNCS_ONCE([mbsrtowcs])
+  if test $ac_cv_func_mbsrtowcs = no; then
+    HAVE_MBSRTOWCS=0
+    AC_CHECK_DECLS([mbsrtowcs],,, [[
+      #include <wchar.h>
+    ]])
+    if test $ac_cv_have_decl_mbsrtowcs = yes; then
+      dnl On Minix 3.1.8, the system's <wchar.h> declares mbsrtowcs() although
+      dnl it does not have the function. Avoid a collision with gnulib's
+      dnl replacement.
+      REPLACE_MBSRTOWCS=1
+    fi
+  else
+    if test $REPLACE_MBSTATE_T = 1; then
+      REPLACE_MBSRTOWCS=1
+    else
+      gl_MBSRTOWCS_WORKS
+      case "$gl_cv_func_mbsrtowcs_works" in
+        *yes) ;;
+        *) REPLACE_MBSRTOWCS=1 ;;
+      esac
+    fi
+  fi
+])
+
+dnl Test whether mbsrtowcs works.
+dnl Result is gl_cv_func_mbsrtowcs_works.
+
+AC_DEFUN([gl_MBSRTOWCS_WORKS],
+[
+  AC_REQUIRE([AC_PROG_CC])
+  AC_REQUIRE([gt_LOCALE_FR])
+  AC_REQUIRE([gt_LOCALE_FR_UTF8])
+  AC_REQUIRE([gt_LOCALE_JA])
+  AC_REQUIRE([gt_LOCALE_ZH_CN])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_CACHE_CHECK([whether mbsrtowcs works],
+    [gl_cv_func_mbsrtowcs_works],
+    [
+      dnl Initial guess, used when cross-compiling or when no suitable locale
+      dnl is present.
+changequote(,)dnl
+      case "$host_os" in
+                                   # Guess no on HP-UX, Solaris, mingw.
+        hpux* | solaris* | mingw*) gl_cv_func_mbsrtowcs_works="guessing no" ;;
+                                   # Guess yes otherwise.
+        *)                         gl_cv_func_mbsrtowcs_works="guessing yes" ;;
+      esac
+changequote([,])dnl
+      if test $LOCALE_FR != none || test $LOCALE_FR_UTF8 != none || test $LOCALE_JA != none || test $LOCALE_ZH_CN != none; then
+        AC_RUN_IFELSE(
+          [AC_LANG_SOURCE([[
+#include <locale.h>
+#include <string.h>
+#include <wchar.h>
+int main ()
+{
+  int result = 0;
+  /* Test whether the function supports a NULL destination argument.
+     This fails on native Windows.  */
+  if (setlocale (LC_ALL, "$LOCALE_FR") != NULL)
+    {
+      const char input[] = "\337er";
+      const char *src = input;
+      mbstate_t state;
+
+      memset (&state, '\0', sizeof (mbstate_t));
+      if (mbsrtowcs (NULL, &src, 1, &state) != 3
+          || src != input)
+        result |= 1;
+    }
+  /* Test whether the function works when started with a conversion state
+     in non-initial state.  This fails on HP-UX 11.11 and Solaris 10.  */
+  if (setlocale (LC_ALL, "$LOCALE_FR_UTF8") != NULL)
+    {
+      const char input[] = "B\303\274\303\237er";
+      mbstate_t state;
+
+      memset (&state, '\0', sizeof (mbstate_t));
+      if (mbrtowc (NULL, input + 1, 1, &state) == (size_t)(-2))
+        if (!mbsinit (&state))
+          {
+            const char *src = input + 2;
+            if (mbsrtowcs (NULL, &src, 10, &state) != 4)
+              result |= 2;
+          }
+    }
+  if (setlocale (LC_ALL, "$LOCALE_JA") != NULL)
+    {
+      const char input[] = "<\306\374\313\334\270\354>";
+      mbstate_t state;
+
+      memset (&state, '\0', sizeof (mbstate_t));
+      if (mbrtowc (NULL, input + 3, 1, &state) == (size_t)(-2))
+        if (!mbsinit (&state))
+          {
+            const char *src = input + 4;
+            if (mbsrtowcs (NULL, &src, 10, &state) != 3)
+              result |= 4;
+          }
+    }
+  if (setlocale (LC_ALL, "$LOCALE_ZH_CN") != NULL)
+    {
+      const char input[] = "B\250\271\201\060\211\070er";
+      mbstate_t state;
+
+      memset (&state, '\0', sizeof (mbstate_t));
+      if (mbrtowc (NULL, input + 1, 1, &state) == (size_t)(-2))
+        if (!mbsinit (&state))
+          {
+            const char *src = input + 2;
+            if (mbsrtowcs (NULL, &src, 10, &state) != 4)
+              result |= 8;
+          }
+    }
+  return result;
+}]])],
+          [gl_cv_func_mbsrtowcs_works=yes],
+          [gl_cv_func_mbsrtowcs_works=no],
+          [:])
+      fi
+    ])
+])
+
+# Prerequisites of lib/mbsrtowcs.c.
+AC_DEFUN([gl_PREREQ_MBSRTOWCS], [
+  :
+])
diff --git a/m4/mbstate_t.m4 b/m4/mbstate_t.m4
new file mode 100644
index 0000000..226f122
--- /dev/null
+++ b/m4/mbstate_t.m4
@@ -0,0 +1,34 @@
+# mbstate_t.m4 serial 14
+dnl Copyright (C) 2000-2002, 2008-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+# From Paul Eggert.
+
+# BeOS 5 has <wchar.h> but does not define mbstate_t,
+# so you can't declare an object of that type.
+# Check for this incompatibility with Standard C.
+
+# AC_TYPE_MBSTATE_T
+# -----------------
+AC_DEFUN([AC_TYPE_MBSTATE_T],
+[
+   AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS]) dnl for HP-UX 11.11
+
+   AC_CACHE_CHECK([for mbstate_t], [ac_cv_type_mbstate_t],
+     [AC_COMPILE_IFELSE(
+        [AC_LANG_PROGRAM(
+           [AC_INCLUDES_DEFAULT[
+             #include <wchar.h>]],
+           [[mbstate_t x; return sizeof x;]])],
+        [ac_cv_type_mbstate_t=yes],
+        [ac_cv_type_mbstate_t=no])])
+   if test $ac_cv_type_mbstate_t = yes; then
+     AC_DEFINE([HAVE_MBSTATE_T], [1],
+               [Define to 1 if <wchar.h> declares mbstate_t.])
+   else
+     AC_DEFINE([mbstate_t], [int],
+               [Define to a type if <wchar.h> does not define.])
+   fi
+])
diff --git a/m4/mbtowc.m4 b/m4/mbtowc.m4
new file mode 100644
index 0000000..befcffa
--- /dev/null
+++ b/m4/mbtowc.m4
@@ -0,0 +1,24 @@
+# mbtowc.m4 serial 3
+dnl Copyright (C) 2011-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_MBTOWC],
+[
+  AC_REQUIRE([gl_STDLIB_H_DEFAULTS])
+
+  AC_CHECK_FUNCS([mbtowc])
+  if test $ac_cv_func_mbtowc = no; then
+    HAVE_MBTOWC=0
+  else
+    if false; then
+      REPLACE_MBTOWC=1
+    fi
+  fi
+])
+
+# Prerequisites of lib/mbtowc.c.
+AC_DEFUN([gl_PREREQ_MBTOWC], [
+  :
+])
diff --git a/m4/md4.m4 b/m4/md4.m4
new file mode 100644
index 0000000..519095c
--- /dev/null
+++ b/m4/md4.m4
@@ -0,0 +1,12 @@
+# md4.m4 serial 7
+dnl Copyright (C) 2002-2006, 2008-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl Prerequisites of lib/md4.c.
+AC_DEFUN([gl_MD4],
+[
+  AC_REQUIRE([gl_BIGENDIAN])
+  :
+])
diff --git a/m4/md5.m4 b/m4/md5.m4
new file mode 100644
index 0000000..ca213ed
--- /dev/null
+++ b/m4/md5.m4
@@ -0,0 +1,14 @@
+# md5.m4 serial 14
+dnl Copyright (C) 2002-2006, 2008-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_MD5],
+[
+  dnl Prerequisites of lib/md5.c.
+  AC_REQUIRE([gl_BIGENDIAN])
+
+  dnl Determine HAVE_OPENSSL_MD5 and LIB_CRYPTO
+  gl_CRYPTO_CHECK([MD5])
+])
diff --git a/m4/memchr.m4 b/m4/memchr.m4
new file mode 100644
index 0000000..888d2b2
--- /dev/null
+++ b/m4/memchr.m4
@@ -0,0 +1,106 @@
+# memchr.m4 serial 17
+dnl Copyright (C) 2002-2004, 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN_ONCE([gl_FUNC_MEMCHR],
+[
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+
+  dnl Check for prerequisites for memory fence checks.
+  gl_FUNC_MMAP_ANON
+  AC_CHECK_HEADERS_ONCE([sys/mman.h])
+  AC_CHECK_FUNCS_ONCE([mprotect])
+
+  AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS])
+  # Detect platform-specific bugs in some versions of glibc:
+  # memchr should not dereference anything with length 0
+  #   https://bugzilla.redhat.com/show_bug.cgi?id=499689
+  # memchr should not dereference overestimated length after a match
+  #   https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=521737
+  #   https://sourceware.org/bugzilla/show_bug.cgi?id=10162
+  # memchr should cast the second argument to 'unsigned char'.
+  #   This bug exists in Android 4.3.
+  # Assume that memchr works on platforms that lack mprotect.
+  AC_CACHE_CHECK([whether memchr works], [gl_cv_func_memchr_works],
+    [AC_RUN_IFELSE([AC_LANG_PROGRAM([[
+#include <string.h>
+#if HAVE_SYS_MMAN_H
+# include <fcntl.h>
+# include <unistd.h>
+# include <sys/types.h>
+# include <sys/mman.h>
+# ifndef MAP_FILE
+#  define MAP_FILE 0
+# endif
+#endif
+]], [[
+  int result = 0;
+  char *fence = NULL;
+#if HAVE_SYS_MMAN_H && HAVE_MPROTECT
+# if HAVE_MAP_ANONYMOUS
+  const int flags = MAP_ANONYMOUS | MAP_PRIVATE;
+  const int fd = -1;
+# else /* !HAVE_MAP_ANONYMOUS */
+  const int flags = MAP_FILE | MAP_PRIVATE;
+  int fd = open ("/dev/zero", O_RDONLY, 0666);
+  if (fd >= 0)
+# endif
+    {
+      int pagesize = getpagesize ();
+      char *two_pages =
+        (char *) mmap (NULL, 2 * pagesize, PROT_READ | PROT_WRITE,
+                       flags, fd, 0);
+      if (two_pages != (char *)(-1)
+          && mprotect (two_pages + pagesize, pagesize, PROT_NONE) == 0)
+        fence = two_pages + pagesize;
+    }
+#endif
+  if (fence)
+    {
+      /* Test against bugs on glibc systems.  */
+      if (memchr (fence, 0, 0))
+        result |= 1;
+      strcpy (fence - 9, "12345678");
+      if (memchr (fence - 9, 0, 79) != fence - 1)
+        result |= 2;
+      if (memchr (fence - 1, 0, 3) != fence - 1)
+        result |= 4;
+      /* Test against bug on AIX 7.2.  */
+      if (memchr (fence - 4, '6', 16) != fence - 4)
+        result |= 8;
+    }
+  /* Test against bug on Android 4.3.  */
+  {
+    char input[3];
+    input[0] = 'a';
+    input[1] = 'b';
+    input[2] = 'c';
+    if (memchr (input, 0x789abc00 | 'b', 3) != input + 1)
+      result |= 16;
+  }
+  return result;
+]])],
+       [gl_cv_func_memchr_works=yes],
+       [gl_cv_func_memchr_works=no],
+       [case "$host_os" in
+                           # Guess no on Android.
+          linux*-android*) gl_cv_func_memchr_works="guessing no" ;;
+                           # Guess yes on native Windows.
+          mingw*)          gl_cv_func_memchr_works="guessing yes" ;;
+                           # If we don't know, obey --enable-cross-guesses.
+          *)               gl_cv_func_memchr_works="$gl_cross_guess_normal" ;;
+        esac
+       ])
+    ])
+  case "$gl_cv_func_memchr_works" in
+    *yes) ;;
+    *) REPLACE_MEMCHR=1 ;;
+  esac
+])
+
+# Prerequisites of lib/memchr.c.
+AC_DEFUN([gl_PREREQ_MEMCHR], [
+  AC_CHECK_HEADERS([bp-sym.h])
+])
diff --git a/m4/mempcpy.m4 b/m4/mempcpy.m4
new file mode 100644
index 0000000..899f12a
--- /dev/null
+++ b/m4/mempcpy.m4
@@ -0,0 +1,26 @@
+# mempcpy.m4 serial 11
+dnl Copyright (C) 2003-2004, 2006-2007, 2009-2020 Free Software Foundation,
+dnl Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_MEMPCPY],
+[
+  dnl Persuade glibc <string.h> to declare mempcpy().
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
+
+  dnl The mempcpy() declaration in lib/string.in.h uses 'restrict'.
+  AC_REQUIRE([AC_C_RESTRICT])
+
+  AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS])
+  AC_CHECK_FUNCS([mempcpy])
+  if test $ac_cv_func_mempcpy = no; then
+    HAVE_MEMPCPY=0
+  fi
+])
+
+# Prerequisites of lib/mempcpy.c.
+AC_DEFUN([gl_PREREQ_MEMPCPY], [
+  :
+])
diff --git a/m4/memrchr.m4 b/m4/memrchr.m4
new file mode 100644
index 0000000..95990ed
--- /dev/null
+++ b/m4/memrchr.m4
@@ -0,0 +1,23 @@
+# memrchr.m4 serial 10
+dnl Copyright (C) 2002-2003, 2005-2007, 2009-2020 Free Software Foundation,
+dnl Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_MEMRCHR],
+[
+  dnl Persuade glibc <string.h> to declare memrchr().
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
+
+  AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS])
+  AC_CHECK_DECLS_ONCE([memrchr])
+  if test $ac_cv_have_decl_memrchr = no; then
+    HAVE_DECL_MEMRCHR=0
+  fi
+
+  AC_CHECK_FUNCS([memrchr])
+])
+
+# Prerequisites of lib/memrchr.c.
+AC_DEFUN([gl_PREREQ_MEMRCHR], [:])
diff --git a/m4/minmax.m4 b/m4/minmax.m4
new file mode 100644
index 0000000..e5b28b0
--- /dev/null
+++ b/m4/minmax.m4
@@ -0,0 +1,44 @@
+# minmax.m4 serial 4
+dnl Copyright (C) 2005, 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_PREREQ([2.53])
+
+AC_DEFUN([gl_MINMAX],
+[
+  AC_REQUIRE([gl_PREREQ_MINMAX])
+])
+
+# Prerequisites of lib/minmax.h.
+AC_DEFUN([gl_PREREQ_MINMAX],
+[
+  gl_MINMAX_IN_HEADER([limits.h])
+  gl_MINMAX_IN_HEADER([sys/param.h])
+])
+
+dnl gl_MINMAX_IN_HEADER(HEADER)
+dnl The parameter has to be a literal header name; it cannot be macro,
+dnl nor a shell variable. (Because autoheader collects only AC_DEFINE
+dnl invocations with a literal macro name.)
+AC_DEFUN([gl_MINMAX_IN_HEADER],
+[
+  m4_pushdef([header], AS_TR_SH([$1]))
+  m4_pushdef([HEADER], AS_TR_CPP([$1]))
+  AC_CACHE_CHECK([whether <$1> defines MIN and MAX],
+    [gl_cv_minmax_in_]header,
+    [AC_COMPILE_IFELSE(
+       [AC_LANG_PROGRAM(
+          [[#include <$1>
+            int x = MIN (42, 17);]],
+          [[]])],
+       [gl_cv_minmax_in_]header[=yes],
+       [gl_cv_minmax_in_]header[=no])])
+  if test $gl_cv_minmax_in_[]header = yes; then
+    AC_DEFINE([HAVE_MINMAX_IN_]HEADER, 1,
+      [Define to 1 if <$1> defines the MIN and MAX macros.])
+  fi
+  m4_popdef([HEADER])
+  m4_popdef([header])
+])
diff --git a/m4/mkdir.m4 b/m4/mkdir.m4
new file mode 100644
index 0000000..bd9e088
--- /dev/null
+++ b/m4/mkdir.m4
@@ -0,0 +1,87 @@
+# serial 17
+
+# Copyright (C) 2001, 2003-2004, 2006, 2008-2020 Free Software Foundation, Inc.
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+# On some systems, mkdir ("foo/", 0700) fails because of the trailing slash.
+# On others, mkdir ("foo/./", 0700) mistakenly succeeds.
+# On such systems, arrange to use a wrapper function.
+AC_DEFUN([gl_FUNC_MKDIR],
+[dnl
+  AC_REQUIRE([gl_SYS_STAT_H_DEFAULTS])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_CHECK_HEADERS_ONCE([unistd.h])
+  AC_CACHE_CHECK([whether mkdir handles trailing slash],
+    [gl_cv_func_mkdir_trailing_slash_works],
+    [rm -rf conftest.dir
+     AC_RUN_IFELSE(
+       [AC_LANG_PROGRAM([[
+          #include <sys/types.h>
+          #include <sys/stat.h>
+          ]GL_MDA_DEFINES],
+          [[return mkdir ("conftest.dir/", 0700);]])],
+       [gl_cv_func_mkdir_trailing_slash_works=yes],
+       [gl_cv_func_mkdir_trailing_slash_works=no],
+       [case "$host_os" in
+                           # Guess yes on Linux systems.
+          linux-* | linux) gl_cv_func_mkdir_trailing_slash_works="guessing yes" ;;
+                           # Guess yes on glibc systems.
+          *-gnu* | gnu*)   gl_cv_func_mkdir_trailing_slash_works="guessing yes" ;;
+                           # Guess yes on MSVC, no on mingw.
+          mingw*)          AC_EGREP_CPP([Known], [
+#ifdef _MSC_VER
+ Known
+#endif
+                             ],
+                             [gl_cv_func_mkdir_trailing_slash_works="guessing yes"],
+                             [gl_cv_func_mkdir_trailing_slash_works="guessing no"])
+                           ;;
+                           # If we don't know, obey --enable-cross-guesses.
+          *)               gl_cv_func_mkdir_trailing_slash_works="$gl_cross_guess_normal" ;;
+        esac
+       ])
+     rm -rf conftest.dir
+    ])
+  case "$gl_cv_func_mkdir_trailing_slash_works" in
+    *yes) ;;
+    *)
+      REPLACE_MKDIR=1
+      ;;
+  esac
+
+  AC_CACHE_CHECK([whether mkdir handles trailing dot],
+    [gl_cv_func_mkdir_trailing_dot_works],
+    [rm -rf conftest.dir
+     AC_RUN_IFELSE(
+       [AC_LANG_PROGRAM([[
+          #include <sys/types.h>
+          #include <sys/stat.h>
+          ]GL_MDA_DEFINES],
+          [[return !mkdir ("conftest.dir/./", 0700);]])],
+       [gl_cv_func_mkdir_trailing_dot_works=yes],
+       [gl_cv_func_mkdir_trailing_dot_works=no],
+       [case "$host_os" in
+                         # Guess yes on glibc systems.
+          *-gnu* | gnu*) gl_cv_func_mkdir_trailing_dot_works="guessing yes" ;;
+                         # Guess yes on musl systems.
+          *-musl*)       gl_cv_func_mkdir_trailing_dot_works="guessing yes" ;;
+                         # Guess no on native Windows.
+          mingw*)        gl_cv_func_mkdir_trailing_dot_works="guessing no" ;;
+                         # If we don't know, obey --enable-cross-guesses.
+          *)             gl_cv_func_mkdir_trailing_dot_works="$gl_cross_guess_normal" ;;
+        esac
+       ])
+     rm -rf conftest.dir
+    ]
+  )
+  case "$gl_cv_func_mkdir_trailing_dot_works" in
+    *yes) ;;
+    *)
+      REPLACE_MKDIR=1
+      AC_DEFINE([FUNC_MKDIR_DOT_BUG], [1], [Define to 1 if mkdir mistakenly
+        creates a directory given with a trailing dot component.])
+      ;;
+  esac
+])
diff --git a/m4/mkostemp.m4 b/m4/mkostemp.m4
new file mode 100644
index 0000000..3e5b555
--- /dev/null
+++ b/m4/mkostemp.m4
@@ -0,0 +1,23 @@
+# mkostemp.m4 serial 2
+dnl Copyright (C) 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_MKOSTEMP],
+[
+  AC_REQUIRE([gl_STDLIB_H_DEFAULTS])
+
+  dnl Persuade glibc <stdlib.h> to declare mkostemp().
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
+
+  AC_CHECK_FUNCS_ONCE([mkostemp])
+  if test $ac_cv_func_mkostemp != yes; then
+    HAVE_MKOSTEMP=0
+  fi
+])
+
+# Prerequisites of lib/mkostemp.c.
+AC_DEFUN([gl_PREREQ_MKOSTEMP],
+[
+])
diff --git a/m4/mkstemp.m4 b/m4/mkstemp.m4
new file mode 100644
index 0000000..392f97c
--- /dev/null
+++ b/m4/mkstemp.m4
@@ -0,0 +1,87 @@
+#serial 28
+
+# Copyright (C) 2001, 2003-2007, 2009-2020 Free Software Foundation, Inc.
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+# On some hosts (e.g., HP-UX 10.20, SunOS 4.1.4, Solaris 2.5.1), mkstemp has a
+# silly limit that it can create no more than 26 files from a given template.
+# Other systems lack mkstemp altogether.
+# On OSF1/Tru64 V4.0F, the system-provided mkstemp function can create
+# only 32 files per process.
+# On some hosts, mkstemp creates files with mode 0666, which is a security
+# problem and a violation of POSIX 2008.
+# On systems like the above, arrange to use the replacement function.
+AC_DEFUN([gl_FUNC_MKSTEMP],
+[
+  AC_REQUIRE([gl_STDLIB_H_DEFAULTS])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+
+  AC_CHECK_FUNCS_ONCE([mkstemp])
+  if test $ac_cv_func_mkstemp = yes; then
+    AC_CACHE_CHECK([for working mkstemp],
+      [gl_cv_func_working_mkstemp],
+      [
+        mkdir conftest.mkstemp
+        AC_RUN_IFELSE(
+          [AC_LANG_PROGRAM(
+            [AC_INCLUDES_DEFAULT
+             GL_MDA_DEFINES],
+            [[int result = 0;
+              int i;
+              off_t large = (off_t) 4294967295u;
+              if (large < 0)
+                large = 2147483647;
+              umask (0);
+              for (i = 0; i < 70; i++)
+                {
+                  char templ[] = "conftest.mkstemp/coXXXXXX";
+                  int (*mkstemp_function) (char *) = mkstemp;
+                  int fd = mkstemp_function (templ);
+                  if (fd < 0)
+                    result |= 1;
+                  else
+                    {
+                      struct stat st;
+                      if (lseek (fd, large, SEEK_SET) != large)
+                        result |= 2;
+                      if (fstat (fd, &st) < 0)
+                        result |= 4;
+                      else if (st.st_mode & 0077)
+                        result |= 8;
+                      if (close (fd))
+                        result |= 16;
+                    }
+                }
+              return result;]])],
+          [gl_cv_func_working_mkstemp=yes],
+          [gl_cv_func_working_mkstemp=no],
+          [case "$host_os" in
+                            # Guess yes on glibc systems.
+             *-gnu* | gnu*) gl_cv_func_working_mkstemp="guessing yes" ;;
+                            # Guess yes on musl systems.
+             *-musl*)       gl_cv_func_working_mkstemp="guessing yes" ;;
+                            # Guess no on native Windows.
+             mingw*)        gl_cv_func_working_mkstemp="guessing no" ;;
+                            # If we don't know, obey --enable-cross-guesses.
+             *)             gl_cv_func_working_mkstemp="$gl_cross_guess_normal" ;;
+           esac
+          ])
+        rm -rf conftest.mkstemp
+      ])
+    case "$gl_cv_func_working_mkstemp" in
+      *yes) ;;
+      *)
+        REPLACE_MKSTEMP=1
+        ;;
+    esac
+  else
+    HAVE_MKSTEMP=0
+  fi
+])
+
+# Prerequisites of lib/mkstemp.c.
+AC_DEFUN([gl_PREREQ_MKSTEMP],
+[
+])
diff --git a/m4/mktime.m4 b/m4/mktime.m4
new file mode 100644
index 0000000..4e7e423
--- /dev/null
+++ b/m4/mktime.m4
@@ -0,0 +1,298 @@
+# serial 35
+dnl Copyright (C) 2002-2003, 2005-2007, 2009-2020 Free Software Foundation,
+dnl Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl From Jim Meyering.
+
+AC_DEFUN([gl_TIME_T_IS_SIGNED],
+[
+  AC_CACHE_CHECK([whether time_t is signed],
+    [gl_cv_time_t_is_signed],
+    [AC_COMPILE_IFELSE(
+       [AC_LANG_PROGRAM([[#include <time.h>
+                          char time_t_signed[(time_t) -1 < 0 ? 1 : -1];]])],
+       [gl_cv_time_t_is_signed=yes],
+       [gl_cv_time_t_is_signed=no])])
+  if test $gl_cv_time_t_is_signed = yes; then
+    AC_DEFINE([TIME_T_IS_SIGNED], [1], [Define to 1 if time_t is signed.])
+  fi
+])
+
+dnl Test whether mktime works. Set gl_cv_func_working_mktime.
+AC_DEFUN([gl_FUNC_MKTIME_WORKS],
+[
+  AC_REQUIRE([gl_TIME_T_IS_SIGNED])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+
+  dnl We don't use AC_FUNC_MKTIME any more, because it is no longer maintained
+  dnl in Autoconf and because it invokes AC_LIBOBJ.
+  AC_CHECK_HEADERS_ONCE([unistd.h])
+  AC_CHECK_DECLS_ONCE([alarm])
+  AC_REQUIRE([gl_MULTIARCH])
+  AC_CACHE_CHECK([for working mktime], [gl_cv_func_working_mktime],
+    [if test $APPLE_UNIVERSAL_BUILD = 1; then
+       # A universal build on Apple Mac OS X platforms.
+       # The test result would be 'yes' in 32-bit mode and 'no' in 64-bit mode.
+       # But we need a configuration result that is valid in both modes.
+       gl_cv_func_working_mktime="guessing no"
+     else
+       AC_RUN_IFELSE(
+         [AC_LANG_SOURCE(
+[[/* Test program from Paul Eggert and Tony Leneis.  */
+#include <limits.h>
+#include <stdlib.h>
+#include <time.h>
+
+#ifdef HAVE_UNISTD_H
+# include <unistd.h>
+#endif
+
+#if HAVE_DECL_ALARM
+# include <signal.h>
+#endif
+
+]GL_MDA_DEFINES[
+
+#ifndef TIME_T_IS_SIGNED
+# define TIME_T_IS_SIGNED 0
+#endif
+
+static time_t time_t_max;
+static time_t time_t_min;
+
+/* Values we'll use to set the TZ environment variable.  */
+static char *tz_strings[] = {
+  (char *) 0, "TZ=GMT0", "TZ=JST-9",
+  "TZ=EST+3EDT+2,M10.1.0/00:00:00,M2.3.0/00:00:00"
+};
+#define N_STRINGS (sizeof (tz_strings) / sizeof (tz_strings[0]))
+
+/* Return 0 if mktime fails to convert a date in the spring-forward gap.
+   Based on a problem report from Andreas Jaeger.  */
+static int
+spring_forward_gap ()
+{
+  /* glibc (up to about 1998-10-07) failed this test. */
+  struct tm tm;
+
+  /* Use the portable POSIX.1 specification "TZ=PST8PDT,M4.1.0,M10.5.0"
+     instead of "TZ=America/Vancouver" in order to detect the bug even
+     on systems that don't support the Olson extension, or don't have the
+     full zoneinfo tables installed.  */
+  putenv ("TZ=PST8PDT,M4.1.0,M10.5.0");
+
+  tm.tm_year = 98;
+  tm.tm_mon = 3;
+  tm.tm_mday = 5;
+  tm.tm_hour = 2;
+  tm.tm_min = 0;
+  tm.tm_sec = 0;
+  tm.tm_isdst = -1;
+  return mktime (&tm) != (time_t) -1;
+}
+
+static int
+mktime_test1 (time_t now)
+{
+  struct tm *lt;
+  return ! (lt = localtime (&now)) || mktime (lt) == now;
+}
+
+static int
+mktime_test (time_t now)
+{
+  return (mktime_test1 (now)
+          && mktime_test1 ((time_t) (time_t_max - now))
+          && mktime_test1 ((time_t) (time_t_min + now)));
+}
+
+static int
+irix_6_4_bug ()
+{
+  /* Based on code from Ariel Faigon.  */
+  struct tm tm;
+  tm.tm_year = 96;
+  tm.tm_mon = 3;
+  tm.tm_mday = 0;
+  tm.tm_hour = 0;
+  tm.tm_min = 0;
+  tm.tm_sec = 0;
+  tm.tm_isdst = -1;
+  mktime (&tm);
+  return tm.tm_mon == 2 && tm.tm_mday == 31;
+}
+
+static int
+bigtime_test (int j)
+{
+  struct tm tm;
+  time_t now;
+  tm.tm_year = tm.tm_mon = tm.tm_mday = tm.tm_hour = tm.tm_min = tm.tm_sec = j;
+  now = mktime (&tm);
+  if (now != (time_t) -1)
+    {
+      struct tm *lt = localtime (&now);
+      if (! (lt
+             && lt->tm_year == tm.tm_year
+             && lt->tm_mon == tm.tm_mon
+             && lt->tm_mday == tm.tm_mday
+             && lt->tm_hour == tm.tm_hour
+             && lt->tm_min == tm.tm_min
+             && lt->tm_sec == tm.tm_sec
+             && lt->tm_yday == tm.tm_yday
+             && lt->tm_wday == tm.tm_wday
+             && ((lt->tm_isdst < 0 ? -1 : 0 < lt->tm_isdst)
+                  == (tm.tm_isdst < 0 ? -1 : 0 < tm.tm_isdst))))
+        return 0;
+    }
+  return 1;
+}
+
+static int
+year_2050_test ()
+{
+  /* The correct answer for 2050-02-01 00:00:00 in Pacific time,
+     ignoring leap seconds.  */
+  unsigned long int answer = 2527315200UL;
+
+  struct tm tm;
+  time_t t;
+  tm.tm_year = 2050 - 1900;
+  tm.tm_mon = 2 - 1;
+  tm.tm_mday = 1;
+  tm.tm_hour = tm.tm_min = tm.tm_sec = 0;
+  tm.tm_isdst = -1;
+
+  /* Use the portable POSIX.1 specification "TZ=PST8PDT,M4.1.0,M10.5.0"
+     instead of "TZ=America/Vancouver" in order to detect the bug even
+     on systems that don't support the Olson extension, or don't have the
+     full zoneinfo tables installed.  */
+  putenv ("TZ=PST8PDT,M4.1.0,M10.5.0");
+
+  t = mktime (&tm);
+
+  /* Check that the result is either a failure, or close enough
+     to the correct answer that we can assume the discrepancy is
+     due to leap seconds.  */
+  return (t == (time_t) -1
+          || (0 < t && answer - 120 <= t && t <= answer + 120));
+}
+
+int
+main ()
+{
+  int result = 0;
+  time_t t, delta;
+  int i, j;
+  int time_t_signed_magnitude = (time_t) ~ (time_t) 0 < (time_t) -1;
+
+#if HAVE_DECL_ALARM
+  /* This test makes some buggy mktime implementations loop.
+     Give up after 60 seconds; a mktime slower than that
+     isn't worth using anyway.  */
+  signal (SIGALRM, SIG_DFL);
+  alarm (60);
+#endif
+
+  time_t_max = (! TIME_T_IS_SIGNED
+                ? (time_t) -1
+                : ((((time_t) 1 << (sizeof (time_t) * CHAR_BIT - 2)) - 1)
+                   * 2 + 1));
+  time_t_min = (! TIME_T_IS_SIGNED
+                ? (time_t) 0
+                : time_t_signed_magnitude
+                ? ~ (time_t) 0
+                : ~ time_t_max);
+
+  delta = time_t_max / 997; /* a suitable prime number */
+  for (i = 0; i < N_STRINGS; i++)
+    {
+      if (tz_strings[i])
+        putenv (tz_strings[i]);
+
+      for (t = 0; t <= time_t_max - delta && (result & 1) == 0; t += delta)
+        if (! mktime_test (t))
+          result |= 1;
+      if ((result & 2) == 0
+          && ! (mktime_test ((time_t) 1)
+                && mktime_test ((time_t) (60 * 60))
+                && mktime_test ((time_t) (60 * 60 * 24))))
+        result |= 2;
+
+      for (j = 1; (result & 4) == 0; j <<= 1)
+        {
+          if (! bigtime_test (j))
+            result |= 4;
+          if (INT_MAX / 2 < j)
+            break;
+        }
+      if ((result & 8) == 0 && ! bigtime_test (INT_MAX))
+        result |= 8;
+    }
+  if (! irix_6_4_bug ())
+    result |= 16;
+  if (! spring_forward_gap ())
+    result |= 32;
+  if (! year_2050_test ())
+    result |= 64;
+  return result;
+}]])],
+         [gl_cv_func_working_mktime=yes],
+         [gl_cv_func_working_mktime=no],
+         [case "$host_os" in
+                    # Guess no on native Windows.
+            mingw*) gl_cv_func_working_mktime="guessing no" ;;
+            *)      gl_cv_func_working_mktime="$gl_cross_guess_normal" ;;
+          esac
+         ])
+     fi
+    ])
+])
+
+dnl Main macro of module 'mktime'.
+AC_DEFUN([gl_FUNC_MKTIME],
+[
+  AC_REQUIRE([gl_HEADER_TIME_H_DEFAULTS])
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  AC_REQUIRE([gl_FUNC_MKTIME_WORKS])
+
+  REPLACE_MKTIME=0
+  if test "$gl_cv_func_working_mktime" != yes; then
+    REPLACE_MKTIME=1
+    AC_DEFINE([NEED_MKTIME_WORKING], [1],
+      [Define if the compilation of mktime.c should define 'mktime'
+       with the algorithmic workarounds.])
+  fi
+  case "$host_os" in
+    mingw*)
+      REPLACE_MKTIME=1
+      AC_DEFINE([NEED_MKTIME_WINDOWS], [1],
+        [Define if the compilation of mktime.c should define 'mktime'
+         with the native Windows TZ workaround.])
+      ;;
+  esac
+])
+
+dnl Main macro of module 'mktime-internal'.
+AC_DEFUN([gl_FUNC_MKTIME_INTERNAL], [
+  AC_REQUIRE([gl_FUNC_MKTIME_WORKS])
+
+  WANT_MKTIME_INTERNAL=0
+  dnl BeOS has __mktime_internal in libc, but other platforms don't.
+  AC_CHECK_FUNC([__mktime_internal],
+    [AC_DEFINE([mktime_internal], [__mktime_internal],
+       [Define to the real name of the mktime_internal function.])
+    ],
+    [dnl mktime works but it doesn't export __mktime_internal,
+     dnl so we need to substitute our own mktime implementation.
+     WANT_MKTIME_INTERNAL=1
+     AC_DEFINE([NEED_MKTIME_INTERNAL], [1],
+       [Define if the compilation of mktime.c should define 'mktime_internal'.])
+    ])
+])
+
+# Prerequisites of lib/mktime.c.
+AC_DEFUN([gl_PREREQ_MKTIME], [:])
diff --git a/m4/mmap-anon.m4 b/m4/mmap-anon.m4
new file mode 100644
index 0000000..2995ad5
--- /dev/null
+++ b/m4/mmap-anon.m4
@@ -0,0 +1,55 @@
+# mmap-anon.m4 serial 11
+dnl Copyright (C) 2005, 2007, 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+# Detect how mmap can be used to create anonymous (not file-backed) memory
+# mappings.
+# - On Linux, AIX, OSF/1, Solaris, Cygwin, Interix, Haiku, both MAP_ANONYMOUS
+#   and MAP_ANON exist and have the same value.
+# - On HP-UX, only MAP_ANONYMOUS exists.
+# - On Mac OS X, FreeBSD, NetBSD, OpenBSD, Minix, only MAP_ANON exists.
+# - On IRIX, neither exists, and a file descriptor opened to /dev/zero must be
+#   used.
+
+AC_DEFUN([gl_FUNC_MMAP_ANON],
+[
+  dnl Persuade glibc <sys/mman.h> to define MAP_ANONYMOUS.
+  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+
+  # Check for mmap(). Don't use AC_FUNC_MMAP, because it checks too much: it
+  # fails on HP-UX 11, because MAP_FIXED mappings do not work. But this is
+  # irrelevant for anonymous mappings.
+  AC_CHECK_FUNC([mmap], [gl_have_mmap=yes], [gl_have_mmap=no])
+
+  # Try to allow MAP_ANONYMOUS.
+  gl_have_mmap_anonymous=no
+  if test $gl_have_mmap = yes; then
+    AC_MSG_CHECKING([for MAP_ANONYMOUS])
+    AC_EGREP_CPP([I cannot identify this map], [
+#include <sys/mman.h>
+#ifdef MAP_ANONYMOUS
+    I cannot identify this map
+#endif
+],
+      [gl_have_mmap_anonymous=yes])
+    if test $gl_have_mmap_anonymous != yes; then
+      AC_EGREP_CPP([I cannot identify this map], [
+#include <sys/mman.h>
+#ifdef MAP_ANON
+    I cannot identify this map
+#endif
+],
+        [AC_DEFINE([MAP_ANONYMOUS], [MAP_ANON],
+          [Define to a substitute value for mmap()'s MAP_ANONYMOUS flag.])
+         gl_have_mmap_anonymous=yes])
+    fi
+    AC_MSG_RESULT([$gl_have_mmap_anonymous])
+    if test $gl_have_mmap_anonymous = yes; then
+      AC_DEFINE([HAVE_MAP_ANONYMOUS], [1],
+        [Define to 1 if mmap()'s MAP_ANONYMOUS flag is available after including
+         config.h and <sys/mman.h>.])
+    fi
+  fi
+])
diff --git a/m4/mode_t.m4 b/m4/mode_t.m4
new file mode 100644
index 0000000..f190951
--- /dev/null
+++ b/m4/mode_t.m4
@@ -0,0 +1,26 @@
+# mode_t.m4 serial 2
+dnl Copyright (C) 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+# For using mode_t, it's sufficient to use AC_TYPE_MODE_T and
+# include <sys/types.h>.
+
+# Define PROMOTED_MODE_T to the type that is the result of "default argument
+# promotion" (ISO C 6.5.2.2.(6)) of the type mode_t.
+AC_DEFUN([gl_PROMOTED_TYPE_MODE_T],
+[
+  AC_REQUIRE([AC_TYPE_MODE_T])
+  AC_CACHE_CHECK([for promoted mode_t type], [gl_cv_promoted_mode_t], [
+    dnl Assume mode_t promotes to 'int' if and only if it is smaller than 'int',
+    dnl and to itself otherwise. This assumption is not guaranteed by the ISO C
+    dnl standard, but we don't know of any real-world counterexamples.
+    AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <sys/types.h>]],
+      [[typedef int array[2 * (sizeof (mode_t) < sizeof (int)) - 1];]])],
+      [gl_cv_promoted_mode_t='int'],
+      [gl_cv_promoted_mode_t='mode_t'])
+  ])
+  AC_DEFINE_UNQUOTED([PROMOTED_MODE_T], [$gl_cv_promoted_mode_t],
+    [Define to the type that is the result of default argument promotions of type mode_t.])
+])
diff --git a/m4/msvc-inval.m4 b/m4/msvc-inval.m4
new file mode 100644
index 0000000..dcf398d
--- /dev/null
+++ b/m4/msvc-inval.m4
@@ -0,0 +1,19 @@
+# msvc-inval.m4 serial 1
+dnl Copyright (C) 2011-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_MSVC_INVAL],
+[
+  AC_CHECK_FUNCS_ONCE([_set_invalid_parameter_handler])
+  if test $ac_cv_func__set_invalid_parameter_handler = yes; then
+    HAVE_MSVC_INVALID_PARAMETER_HANDLER=1
+    AC_DEFINE([HAVE_MSVC_INVALID_PARAMETER_HANDLER], [1],
+      [Define to 1 on MSVC platforms that have the "invalid parameter handler"
+       concept.])
+  else
+    HAVE_MSVC_INVALID_PARAMETER_HANDLER=0
+  fi
+  AC_SUBST([HAVE_MSVC_INVALID_PARAMETER_HANDLER])
+])
diff --git a/m4/msvc-nothrow.m4 b/m4/msvc-nothrow.m4
new file mode 100644
index 0000000..13198d8
--- /dev/null
+++ b/m4/msvc-nothrow.m4
@@ -0,0 +1,10 @@
+# msvc-nothrow.m4 serial 1
+dnl Copyright (C) 2011-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_MSVC_NOTHROW],
+[
+  AC_REQUIRE([gl_MSVC_INVAL])
+])
diff --git a/m4/multiarch.m4 b/m4/multiarch.m4
new file mode 100644
index 0000000..2c61afb
--- /dev/null
+++ b/m4/multiarch.m4
@@ -0,0 +1,65 @@
+# multiarch.m4 serial 9
+dnl Copyright (C) 2008-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+# Determine whether the compiler is or may be producing universal binaries.
+#
+# On Mac OS X 10.5 and later systems, the user can create libraries and
+# executables that work on multiple system types--known as "fat" or
+# "universal" binaries--by specifying multiple '-arch' options to the
+# compiler but only a single '-arch' option to the preprocessor.  Like
+# this:
+#
+#     ./configure CC="gcc -arch i386 -arch x86_64 -arch ppc -arch ppc64" \
+#                 CXX="g++ -arch i386 -arch x86_64 -arch ppc -arch ppc64" \
+#                 CPP="gcc -E" CXXCPP="g++ -E"
+#
+# Detect this situation and set APPLE_UNIVERSAL_BUILD accordingly.
+
+AC_DEFUN_ONCE([gl_MULTIARCH],
+[
+  dnl Code similar to autoconf-2.63 AC_C_BIGENDIAN.
+  AC_CACHE_CHECK([whether the compiler produces multi-arch binaries],
+    [gl_cv_c_multiarch],
+    [gl_cv_c_multiarch=no
+     AC_COMPILE_IFELSE(
+       [AC_LANG_SOURCE(
+         [[#ifndef __APPLE_CC__
+            not a universal capable compiler
+           #endif
+           typedef int dummy;
+         ]])],
+       [
+        dnl Check for potential -arch flags.  It is not universal unless
+        dnl there are at least two -arch flags with different values.
+        arch=
+        prev=
+        for word in ${CC} ${CFLAGS} ${CPPFLAGS} ${LDFLAGS}; do
+          if test -n "$prev"; then
+            case $word in
+              i?86 | x86_64 | ppc | ppc64 | arm | arm64)
+                if test -z "$arch" || test "$arch" = "$word"; then
+                  arch="$word"
+                else
+                  gl_cv_c_multiarch=yes
+                fi
+                ;;
+            esac
+            prev=
+          else
+            if test "x$word" = "x-arch"; then
+              prev=arch
+            fi
+          fi
+        done
+       ])
+    ])
+  if test $gl_cv_c_multiarch = yes; then
+    APPLE_UNIVERSAL_BUILD=1
+  else
+    APPLE_UNIVERSAL_BUILD=0
+  fi
+  AC_SUBST([APPLE_UNIVERSAL_BUILD])
+])
diff --git a/m4/nanosleep.m4 b/m4/nanosleep.m4
new file mode 100644
index 0000000..1fb13ed
--- /dev/null
+++ b/m4/nanosleep.m4
@@ -0,0 +1,161 @@
+# serial 39
+
+dnl From Jim Meyering.
+dnl Check for the nanosleep function.
+dnl If not found, use the supplied replacement.
+dnl
+
+# Copyright (C) 1999-2001, 2003-2020 Free Software Foundation, Inc.
+
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_NANOSLEEP],
+[
+ AC_REQUIRE([gl_HEADER_TIME_H_DEFAULTS])
+ AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+
+ dnl Persuade glibc and Solaris <time.h> to declare nanosleep.
+ AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+
+ AC_CHECK_HEADERS_ONCE([sys/time.h])
+ AC_REQUIRE([gl_FUNC_SELECT])
+
+ AC_CHECK_DECLS_ONCE([alarm])
+
+ nanosleep_save_libs=$LIBS
+
+ # Solaris 2.5.1 needs -lposix4 to get the nanosleep function.
+ # Solaris 7 prefers the library name -lrt to the obsolescent name -lposix4.
+ LIB_NANOSLEEP=
+ AC_SUBST([LIB_NANOSLEEP])
+ AC_SEARCH_LIBS([nanosleep], [rt posix4],
+                [test "$ac_cv_search_nanosleep" = "none required" ||
+                 LIB_NANOSLEEP=$ac_cv_search_nanosleep])
+ if test "x$ac_cv_search_nanosleep" != xno; then
+   dnl The system has a nanosleep function.
+
+   AC_REQUIRE([gl_MULTIARCH])
+   if test $APPLE_UNIVERSAL_BUILD = 1; then
+     # A universal build on Apple Mac OS X platforms.
+     # The test result would be 'no (mishandles large arguments)' in 64-bit
+     # mode but 'yes' in 32-bit mode. But we need a configuration result that
+     # is valid in both modes.
+     gl_cv_func_nanosleep='no (mishandles large arguments)'
+   fi
+
+   AC_CACHE_CHECK([for working nanosleep],
+    [gl_cv_func_nanosleep],
+    [
+     AC_RUN_IFELSE(
+       [AC_LANG_SOURCE([[
+          #include <errno.h>
+          #include <limits.h>
+          #include <signal.h>
+          #if HAVE_SYS_TIME_H
+           #include <sys/time.h>
+          #endif
+          #include <time.h>
+          #include <unistd.h>
+          #define TYPE_SIGNED(t) (! ((t) 0 < (t) -1))
+          #define TYPE_MAXIMUM(t) \
+            ((t) (! TYPE_SIGNED (t) \
+                  ? (t) -1 \
+                  : ((((t) 1 << (sizeof (t) * CHAR_BIT - 2)) - 1) * 2 + 1)))
+
+          #if HAVE_DECL_ALARM
+          static void
+          check_for_SIGALRM (int sig)
+          {
+            if (sig != SIGALRM)
+              _exit (1);
+          }
+          #endif
+
+          int
+          main ()
+          {
+            static struct timespec ts_sleep;
+            static struct timespec ts_remaining;
+            /* Test for major problems first.  */
+            if (! nanosleep)
+              return 2;
+            ts_sleep.tv_sec = 0;
+            ts_sleep.tv_nsec = 1;
+            #if HAVE_DECL_ALARM
+            {
+              static struct sigaction act;
+              act.sa_handler = check_for_SIGALRM;
+              sigemptyset (&act.sa_mask);
+              sigaction (SIGALRM, &act, NULL);
+              alarm (1);
+              if (nanosleep (&ts_sleep, NULL) != 0)
+                return 3;
+              /* Test for a minor problem: the handling of large arguments.  */
+              ts_sleep.tv_sec = TYPE_MAXIMUM (time_t);
+              ts_sleep.tv_nsec = 999999999;
+              alarm (1);
+              if (nanosleep (&ts_sleep, &ts_remaining) != -1)
+                return 4;
+              if (errno != EINTR)
+                return 5;
+              if (ts_remaining.tv_sec <= TYPE_MAXIMUM (time_t) - 10)
+                return 6;
+            }
+            #else /* A simpler test for native Windows.  */
+            if (nanosleep (&ts_sleep, &ts_remaining) < 0)
+              return 3;
+            #endif
+            return 0;
+          }]])],
+       [gl_cv_func_nanosleep=yes],
+       [case $? in dnl (
+        4|5|6) gl_cv_func_nanosleep='no (mishandles large arguments)';; dnl (
+        *)   gl_cv_func_nanosleep=no;;
+        esac],
+       [case "$host_os" in dnl ((
+          linux*) # Guess it halfway works when the kernel is Linux.
+            gl_cv_func_nanosleep='guessing no (mishandles large arguments)' ;;
+          mingw*) # Guess no on native Windows.
+            gl_cv_func_nanosleep='guessing no' ;;
+          *)      # If we don't know, obey --enable-cross-guesses.
+            gl_cv_func_nanosleep="$gl_cross_guess_normal" ;;
+        esac
+       ])
+    ])
+   case "$gl_cv_func_nanosleep" in
+     *yes)
+       REPLACE_NANOSLEEP=0
+       ;;
+     *)
+       REPLACE_NANOSLEEP=1
+       case "$gl_cv_func_nanosleep" in
+         *"mishandles large arguments"*)
+           AC_DEFINE([HAVE_BUG_BIG_NANOSLEEP], [1],
+             [Define to 1 if nanosleep mishandles large arguments.])
+           ;;
+         *)
+           # The replacement uses select(). Add $LIBSOCKET to $LIB_NANOSLEEP.
+           for ac_lib in $LIBSOCKET; do
+             case " $LIB_NANOSLEEP " in
+               *" $ac_lib "*) ;;
+               *) LIB_NANOSLEEP="$LIB_NANOSLEEP $ac_lib";;
+             esac
+           done
+           ;;
+       esac
+       ;;
+   esac
+ else
+   HAVE_NANOSLEEP=0
+ fi
+ LIBS=$nanosleep_save_libs
+])
+
+# Prerequisites of lib/nanosleep.c.
+AC_DEFUN([gl_PREREQ_NANOSLEEP],
+[
+  AC_CHECK_HEADERS_ONCE([sys/select.h])
+  gl_PREREQ_SIG_HANDLER_H
+])
diff --git a/m4/netdb_h.m4 b/m4/netdb_h.m4
new file mode 100644
index 0000000..143a2c8
--- /dev/null
+++ b/m4/netdb_h.m4
@@ -0,0 +1,44 @@
+# netdb_h.m4 serial 12
+dnl Copyright (C) 2008-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_HEADER_NETDB],
+[
+  AC_REQUIRE([gl_NETDB_H_DEFAULTS])
+  gl_CHECK_NEXT_HEADERS([netdb.h])
+  if test $ac_cv_header_netdb_h = yes; then
+    HAVE_NETDB_H=1
+  else
+    HAVE_NETDB_H=0
+  fi
+  AC_SUBST([HAVE_NETDB_H])
+
+  dnl Check for declarations of anything we want to poison if the
+  dnl corresponding gnulib module is not in use.
+  gl_WARN_ON_USE_PREPARE([[#include <netdb.h>]],
+    [getaddrinfo freeaddrinfo gai_strerror getnameinfo])
+])
+
+AC_DEFUN([gl_NETDB_MODULE_INDICATOR],
+[
+  dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
+  AC_REQUIRE([gl_NETDB_H_DEFAULTS])
+  gl_MODULE_INDICATOR_SET_VARIABLE([$1])
+  dnl Define it also as a C macro, for the benefit of the unit tests.
+  gl_MODULE_INDICATOR_FOR_TESTS([$1])
+])
+
+AC_DEFUN([gl_NETDB_H_DEFAULTS],
+[
+  GNULIB_GETADDRINFO=0; AC_SUBST([GNULIB_GETADDRINFO])
+  dnl Assume proper GNU behavior unless another module says otherwise.
+  HAVE_STRUCT_ADDRINFO=1;   AC_SUBST([HAVE_STRUCT_ADDRINFO])
+  HAVE_DECL_FREEADDRINFO=1; AC_SUBST([HAVE_DECL_FREEADDRINFO])
+  HAVE_DECL_GAI_STRERROR=1; AC_SUBST([HAVE_DECL_GAI_STRERROR])
+  HAVE_DECL_GETADDRINFO=1;  AC_SUBST([HAVE_DECL_GETADDRINFO])
+  HAVE_DECL_GETNAMEINFO=1;  AC_SUBST([HAVE_DECL_GETNAMEINFO])
+  REPLACE_GAI_STRERROR=0;   AC_SUBST([REPLACE_GAI_STRERROR])
+  REPLACE_GETADDRINFO=0;    AC_SUBST([REPLACE_GETADDRINFO])
+])
diff --git a/m4/netinet_in_h.m4 b/m4/netinet_in_h.m4
new file mode 100644
index 0000000..df9f383
--- /dev/null
+++ b/m4/netinet_in_h.m4
@@ -0,0 +1,31 @@
+# netinet_in_h.m4 serial 5
+dnl Copyright (C) 2006-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_HEADER_NETINET_IN],
+[
+  AC_CACHE_CHECK([whether <netinet/in.h> is self-contained],
+    [gl_cv_header_netinet_in_h_selfcontained],
+    [
+      AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <netinet/in.h>]], [[]])],
+        [gl_cv_header_netinet_in_h_selfcontained=yes],
+        [gl_cv_header_netinet_in_h_selfcontained=no])
+    ])
+  if test $gl_cv_header_netinet_in_h_selfcontained = yes; then
+    NETINET_IN_H=''
+  else
+    NETINET_IN_H='netinet/in.h'
+    AC_CHECK_HEADERS([netinet/in.h])
+    gl_CHECK_NEXT_HEADERS([netinet/in.h])
+    if test $ac_cv_header_netinet_in_h = yes; then
+      HAVE_NETINET_IN_H=1
+    else
+      HAVE_NETINET_IN_H=0
+    fi
+    AC_SUBST([HAVE_NETINET_IN_H])
+  fi
+  AC_SUBST([NETINET_IN_H])
+  AM_CONDITIONAL([GL_GENERATE_NETINET_IN_H], [test -n "$NETINET_IN_H"])
+])
diff --git a/m4/nl_langinfo.m4 b/m4/nl_langinfo.m4
new file mode 100644
index 0000000..342afd2
--- /dev/null
+++ b/m4/nl_langinfo.m4
@@ -0,0 +1,77 @@
+# nl_langinfo.m4 serial 8
+dnl Copyright (C) 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_NL_LANGINFO],
+[
+  AC_REQUIRE([gl_LANGINFO_H_DEFAULTS])
+  AC_REQUIRE([gl_LANGINFO_H])
+  AC_CHECK_FUNCS_ONCE([nl_langinfo])
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  AC_REQUIRE([gl_FUNC_SETLOCALE_NULL])
+  AC_REQUIRE([gl_PTHREADLIB])
+  AC_CHECK_HEADERS_ONCE([threads.h])
+  if test $ac_cv_func_nl_langinfo = yes; then
+    # On Irix 6.5, YESEXPR is defined, but nl_langinfo(YESEXPR) is broken.
+    AC_CACHE_CHECK([whether YESEXPR works],
+      [gl_cv_func_nl_langinfo_yesexpr_works],
+      [AC_RUN_IFELSE(
+         [AC_LANG_PROGRAM([[#include <langinfo.h>
+]], [[return !*nl_langinfo(YESEXPR);
+]])],
+         [gl_cv_func_nl_langinfo_yesexpr_works=yes],
+         [gl_cv_func_nl_langinfo_yesexpr_works=no],
+         [
+         case "$host_os" in
+                   # Guess no on irix systems.
+           irix*)  gl_cv_func_nl_langinfo_yesexpr_works="guessing no";;
+                   # Guess yes elsewhere.
+           *)      gl_cv_func_nl_langinfo_yesexpr_works="guessing yes";;
+         esac
+         ])
+      ])
+    case $gl_cv_func_nl_langinfo_yesexpr_works in
+      *yes) FUNC_NL_LANGINFO_YESEXPR_WORKS=1 ;;
+      *)    FUNC_NL_LANGINFO_YESEXPR_WORKS=0 ;;
+    esac
+    AC_DEFINE_UNQUOTED([FUNC_NL_LANGINFO_YESEXPR_WORKS],
+      [$FUNC_NL_LANGINFO_YESEXPR_WORKS],
+      [Define to 1 if nl_langinfo (YESEXPR) returns a non-empty string.])
+    # On Solaris 10 and Solaris 11.3, nl_langinfo is not multithread-safe.
+    case "$host_os" in
+      solaris*) NL_LANGINFO_MTSAFE=0 ;;
+      *)        NL_LANGINFO_MTSAFE=1 ;;
+    esac
+    AC_DEFINE_UNQUOTED([NL_LANGINFO_MTSAFE], [$NL_LANGINFO_MTSAFE],
+      [Define to 1 if nl_langinfo is multithread-safe.])
+    if test $HAVE_LANGINFO_CODESET = 1 \
+       && test $HAVE_LANGINFO_T_FMT_AMPM = 1 \
+       && test $HAVE_LANGINFO_ALTMON = 1 \
+       && test $HAVE_LANGINFO_ERA = 1 \
+       && test $FUNC_NL_LANGINFO_YESEXPR_WORKS = 1 \
+       && test $NL_LANGINFO_MTSAFE = 1; then
+      :
+    else
+      REPLACE_NL_LANGINFO=1
+      AC_DEFINE([REPLACE_NL_LANGINFO], [1],
+        [Define if nl_langinfo exists but is overridden by gnulib.])
+    fi
+  else
+    HAVE_NL_LANGINFO=0
+  fi
+  if test $HAVE_NL_LANGINFO = 0 || test $HAVE_LANGINFO_CODESET = 0; then
+    LIB_NL_LANGINFO="$LIB_SETLOCALE_NULL"
+  else
+    LIB_NL_LANGINFO=
+  fi
+  dnl LIB_NL_LANGINFO is expected to be empty everywhere.
+  AC_SUBST([LIB_NL_LANGINFO])
+])
+
+# Prerequisites of lib/nl_langinfo-lock.c.
+AC_DEFUN([gl_PREREQ_NL_LANGINFO_LOCK],
+[
+  gl_VISIBILITY
+])
diff --git a/m4/nls.m4 b/m4/nls.m4
new file mode 100644
index 0000000..53cdc8b
--- /dev/null
+++ b/m4/nls.m4
@@ -0,0 +1,32 @@
+# nls.m4 serial 5 (gettext-0.18)
+dnl Copyright (C) 1995-2003, 2005-2006, 2008-2014 Free Software Foundation,
+dnl Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+dnl
+dnl This file can can be used in projects which are not available under
+dnl the GNU General Public License or the GNU Library General Public
+dnl License but which still want to provide support for the GNU gettext
+dnl functionality.
+dnl Please note that the actual code of the GNU gettext library is covered
+dnl by the GNU Library General Public License, and the rest of the GNU
+dnl gettext package package is covered by the GNU General Public License.
+dnl They are *not* in the public domain.
+
+dnl Authors:
+dnl   Ulrich Drepper <drepper@cygnus.com>, 1995-2000.
+dnl   Bruno Haible <haible@clisp.cons.org>, 2000-2003.
+
+AC_PREREQ([2.50])
+
+AC_DEFUN([AM_NLS],
+[
+  AC_MSG_CHECKING([whether NLS is requested])
+  dnl Default is enabled NLS
+  AC_ARG_ENABLE([nls],
+    [  --disable-nls           do not use Native Language Support],
+    USE_NLS=$enableval, USE_NLS=yes)
+  AC_MSG_RESULT([$USE_NLS])
+  AC_SUBST([USE_NLS])
+])
diff --git a/m4/nocrash.m4 b/m4/nocrash.m4
new file mode 100644
index 0000000..637a0ea
--- /dev/null
+++ b/m4/nocrash.m4
@@ -0,0 +1,131 @@
+# nocrash.m4 serial 5
+dnl Copyright (C) 2005, 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl Based on libsigsegv, from Bruno Haible and Paolo Bonzini.
+
+AC_PREREQ([2.13])
+
+dnl Expands to some code for use in .c programs that will cause the configure
+dnl test to exit instead of crashing. This is useful to avoid triggering
+dnl action from a background debugger and to avoid core dumps.
+dnl Usage:   ...
+dnl          ]GL_NOCRASH[
+dnl          ...
+dnl          int main() { nocrash_init(); ... }
+AC_DEFUN([GL_NOCRASH],[[
+#include <stdlib.h>
+#if defined __MACH__ && defined __APPLE__
+/* Avoid a crash on Mac OS X.  */
+#include <mach/mach.h>
+#include <mach/mach_error.h>
+#include <mach/thread_status.h>
+#include <mach/exception.h>
+#include <mach/task.h>
+#include <pthread.h>
+/* The exception port on which our thread listens.  */
+static mach_port_t our_exception_port;
+/* The main function of the thread listening for exceptions of type
+   EXC_BAD_ACCESS.  */
+static void *
+mach_exception_thread (void *arg)
+{
+  /* Buffer for a message to be received.  */
+  struct {
+    mach_msg_header_t head;
+    mach_msg_body_t msgh_body;
+    char data[1024];
+  } msg;
+  mach_msg_return_t retval;
+  /* Wait for a message on the exception port.  */
+  retval = mach_msg (&msg.head, MACH_RCV_MSG | MACH_RCV_LARGE, 0, sizeof (msg),
+                     our_exception_port, MACH_MSG_TIMEOUT_NONE, MACH_PORT_NULL);
+  if (retval != MACH_MSG_SUCCESS)
+    abort ();
+  exit (1);
+}
+static void
+nocrash_init (void)
+{
+  mach_port_t self = mach_task_self ();
+  /* Allocate a port on which the thread shall listen for exceptions.  */
+  if (mach_port_allocate (self, MACH_PORT_RIGHT_RECEIVE, &our_exception_port)
+      == KERN_SUCCESS) {
+    /* See https://web.mit.edu/darwin/src/modules/xnu/osfmk/man/mach_port_insert_right.html.  */
+    if (mach_port_insert_right (self, our_exception_port, our_exception_port,
+                                MACH_MSG_TYPE_MAKE_SEND)
+        == KERN_SUCCESS) {
+      /* The exceptions we want to catch.  Only EXC_BAD_ACCESS is interesting
+         for us.  */
+      exception_mask_t mask = EXC_MASK_BAD_ACCESS;
+      /* Create the thread listening on the exception port.  */
+      pthread_attr_t attr;
+      pthread_t thread;
+      if (pthread_attr_init (&attr) == 0
+          && pthread_attr_setdetachstate (&attr, PTHREAD_CREATE_DETACHED) == 0
+          && pthread_create (&thread, &attr, mach_exception_thread, NULL) == 0) {
+        pthread_attr_destroy (&attr);
+        /* Replace the exception port info for these exceptions with our own.
+           Note that we replace the exception port for the entire task, not only
+           for a particular thread.  This has the effect that when our exception
+           port gets the message, the thread specific exception port has already
+           been asked, and we don't need to bother about it.
+           See https://web.mit.edu/darwin/src/modules/xnu/osfmk/man/task_set_exception_ports.html.  */
+        task_set_exception_ports (self, mask, our_exception_port,
+                                  EXCEPTION_DEFAULT, MACHINE_THREAD_STATE);
+      }
+    }
+  }
+}
+#elif defined _WIN32 && ! defined __CYGWIN__
+/* Avoid a crash on native Windows.  */
+#define WIN32_LEAN_AND_MEAN
+#include <windows.h>
+#include <winerror.h>
+static LONG WINAPI
+exception_filter (EXCEPTION_POINTERS *ExceptionInfo)
+{
+  switch (ExceptionInfo->ExceptionRecord->ExceptionCode)
+    {
+    case EXCEPTION_ACCESS_VIOLATION:
+    case EXCEPTION_IN_PAGE_ERROR:
+    case EXCEPTION_STACK_OVERFLOW:
+    case EXCEPTION_GUARD_PAGE:
+    case EXCEPTION_PRIV_INSTRUCTION:
+    case EXCEPTION_ILLEGAL_INSTRUCTION:
+    case EXCEPTION_DATATYPE_MISALIGNMENT:
+    case EXCEPTION_ARRAY_BOUNDS_EXCEEDED:
+    case EXCEPTION_NONCONTINUABLE_EXCEPTION:
+      exit (1);
+    }
+  return EXCEPTION_CONTINUE_SEARCH;
+}
+static void
+nocrash_init (void)
+{
+  SetUnhandledExceptionFilter ((LPTOP_LEVEL_EXCEPTION_FILTER) exception_filter);
+}
+#else
+/* Avoid a crash on POSIX systems.  */
+#include <signal.h>
+#include <unistd.h>
+/* A POSIX signal handler.  */
+static void
+exception_handler (int sig)
+{
+  _exit (1);
+}
+static void
+nocrash_init (void)
+{
+#ifdef SIGSEGV
+  signal (SIGSEGV, exception_handler);
+#endif
+#ifdef SIGBUS
+  signal (SIGBUS, exception_handler);
+#endif
+}
+#endif
+]])
diff --git a/m4/off_t.m4 b/m4/off_t.m4
new file mode 100644
index 0000000..6e19af8
--- /dev/null
+++ b/m4/off_t.m4
@@ -0,0 +1,18 @@
+# off_t.m4 serial 1
+dnl Copyright (C) 2012-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl Check whether to override the 'off_t' type.
+dnl Set WINDOWS_64_BIT_OFF_T.
+
+AC_DEFUN([gl_TYPE_OFF_T],
+[
+  m4_ifdef([gl_LARGEFILE], [
+    AC_REQUIRE([gl_LARGEFILE])
+  ], [
+    WINDOWS_64_BIT_OFF_T=0
+  ])
+  AC_SUBST([WINDOWS_64_BIT_OFF_T])
+])
diff --git a/m4/open-cloexec.m4 b/m4/open-cloexec.m4
new file mode 100644
index 0000000..11652d5
--- /dev/null
+++ b/m4/open-cloexec.m4
@@ -0,0 +1,21 @@
+# Test whether O_CLOEXEC is defined.
+
+dnl Copyright 2017-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_PREPROC_O_CLOEXEC],
+[
+  AC_CACHE_CHECK([for O_CLOEXEC],
+    [gl_cv_macro_O_CLOEXEC],
+    [AC_COMPILE_IFELSE(
+       [AC_LANG_PROGRAM([[#include <fcntl.h>
+                          #ifndef O_CLOEXEC
+                            choke me;
+                          #endif
+                        ]],
+                        [[return O_CLOEXEC;]])],
+       [gl_cv_macro_O_CLOEXEC=yes],
+       [gl_cv_macro_O_CLOEXEC=no])])
+])
diff --git a/m4/open-slash.m4 b/m4/open-slash.m4
new file mode 100644
index 0000000..5d84f2b
--- /dev/null
+++ b/m4/open-slash.m4
@@ -0,0 +1,60 @@
+# open-slash.m4 serial 2
+dnl Copyright (C) 2007-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl Tests whether open() and creat() recognize a trailing slash.
+dnl Sets gl_cv_func_open_slash.
+AC_DEFUN([gl_OPEN_TRAILING_SLASH_BUG],
+[
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  dnl open("foo/") should not create a file when the file name has a
+  dnl trailing slash.  FreeBSD only has the problem on symlinks.
+  AC_CHECK_FUNCS_ONCE([lstat])
+  AC_CACHE_CHECK([whether open recognizes a trailing slash],
+    [gl_cv_func_open_slash],
+    [# Assume that if we have lstat, we can also check symlinks.
+     if test $ac_cv_func_lstat = yes; then
+       touch conftest.tmp
+       ln -s conftest.tmp conftest.lnk
+     fi
+     AC_RUN_IFELSE(
+       [AC_LANG_SOURCE([[
+#include <fcntl.h>
+#if HAVE_UNISTD_H
+# include <unistd.h>
+#endif
+]GL_MDA_DEFINES[
+int main ()
+{
+  int result = 0;
+#if HAVE_LSTAT
+  if (open ("conftest.lnk/", O_RDONLY) != -1)
+    result |= 1;
+#endif
+  if (open ("conftest.sl/", O_CREAT, 0600) >= 0)
+    result |= 2;
+  return result;
+}]])],
+       [gl_cv_func_open_slash=yes],
+       [gl_cv_func_open_slash=no],
+       [
+changequote(,)dnl
+        case "$host_os" in
+          freebsd* | aix* | hpux* | solaris2.[0-9] | solaris2.[0-9].*)
+            gl_cv_func_open_slash="guessing no" ;;
+          *)
+            gl_cv_func_open_slash="guessing yes" ;;
+        esac
+changequote([,])dnl
+       ])
+     rm -f conftest.sl conftest.tmp conftest.lnk
+    ])
+  case "$gl_cv_func_open_slash" in
+    *no)
+      AC_DEFINE([OPEN_TRAILING_SLASH_BUG], [1],
+        [Define to 1 if open() fails to recognize a trailing slash.])
+      ;;
+  esac
+])
diff --git a/m4/open.m4 b/m4/open.m4
new file mode 100644
index 0000000..552eedf
--- /dev/null
+++ b/m4/open.m4
@@ -0,0 +1,56 @@
+# open.m4 serial 15
+dnl Copyright (C) 2007-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_OPEN],
+[
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  AC_REQUIRE([gl_PREPROC_O_CLOEXEC])
+  case "$host_os" in
+    mingw* | pw*)
+      REPLACE_OPEN=1
+      ;;
+    *)
+      dnl open("foo/") should not create a file when the file name has a
+      dnl trailing slash.  FreeBSD only has the problem on symlinks.
+      AC_CHECK_FUNCS_ONCE([lstat])
+      if test "$gl_cv_macro_O_CLOEXEC" != yes; then
+        REPLACE_OPEN=1
+      fi
+      gl_OPEN_TRAILING_SLASH_BUG
+      case "$gl_cv_func_open_slash" in
+        *no)
+          REPLACE_OPEN=1
+          ;;
+      esac
+      ;;
+  esac
+  dnl Replace open() for supporting the gnulib-defined fchdir() function,
+  dnl to keep fchdir's bookkeeping up-to-date.
+  m4_ifdef([gl_FUNC_FCHDIR], [
+    if test $REPLACE_OPEN = 0; then
+      gl_TEST_FCHDIR
+      if test $HAVE_FCHDIR = 0; then
+        REPLACE_OPEN=1
+      fi
+    fi
+  ])
+  dnl Replace open() for supporting the gnulib-defined O_NONBLOCK flag.
+  m4_ifdef([gl_NONBLOCKING_IO], [
+    if test $REPLACE_OPEN = 0; then
+      gl_NONBLOCKING_IO
+      if test $gl_cv_have_open_O_NONBLOCK != yes; then
+        REPLACE_OPEN=1
+      fi
+    fi
+  ])
+])
+
+# Prerequisites of lib/open.c.
+AC_DEFUN([gl_PREREQ_OPEN],
+[
+  AC_REQUIRE([gl_PROMOTED_TYPE_MODE_T])
+  :
+])
diff --git a/m4/openat.m4 b/m4/openat.m4
new file mode 100644
index 0000000..cf9f717
--- /dev/null
+++ b/m4/openat.m4
@@ -0,0 +1,38 @@
+# serial 46
+# See if we need to use our replacement for Solaris' openat et al functions.
+
+dnl Copyright (C) 2004-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+# Written by Jim Meyering.
+
+AC_DEFUN([gl_FUNC_OPENAT],
+[
+  AC_REQUIRE([gl_FCNTL_H_DEFAULTS])
+  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+  AC_CHECK_FUNCS_ONCE([openat])
+  AC_REQUIRE([gl_FUNC_LSTAT_FOLLOWS_SLASHED_SYMLINK])
+  AC_REQUIRE([gl_PREPROC_O_CLOEXEC])
+  case $ac_cv_func_openat+$gl_cv_func_lstat_dereferences_slashed_symlink+$gl_cv_macro_O_CLOEXEC in
+  yes+*yes+yes)
+    ;;
+  yes+*)
+    # Solaris 10 lacks O_CLOEXEC.
+    # Solaris 9 has *at functions, but uniformly mishandles trailing
+    # slash in all of them.
+    REPLACE_OPENAT=1
+    ;;
+  *)
+    HAVE_OPENAT=0
+    ;;
+  esac
+])
+
+# Prerequisites of lib/openat.c.
+AC_DEFUN([gl_PREREQ_OPENAT],
+[
+  AC_REQUIRE([gl_PROMOTED_TYPE_MODE_T])
+  :
+])
diff --git a/m4/opendir.m4 b/m4/opendir.m4
new file mode 100644
index 0000000..fd3c1ec
--- /dev/null
+++ b/m4/opendir.m4
@@ -0,0 +1,32 @@
+# opendir.m4 serial 5
+dnl Copyright (C) 2011-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_OPENDIR],
+[
+  AC_REQUIRE([gl_DIRENT_H_DEFAULTS])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+
+  AC_CHECK_FUNCS([opendir])
+  if test $ac_cv_func_opendir = no; then
+    HAVE_OPENDIR=0
+  fi
+  dnl Replace opendir() for supporting the gnulib-defined fchdir() function,
+  dnl to keep fchdir's bookkeeping up-to-date.
+  m4_ifdef([gl_FUNC_FCHDIR], [
+    gl_TEST_FCHDIR
+    if test $HAVE_FCHDIR = 0; then
+      if test $HAVE_OPENDIR = 1; then
+        REPLACE_OPENDIR=1
+      fi
+    fi
+  ])
+  dnl Replace opendir() on OS/2 kLIBC to support dirfd() function replaced
+  dnl by gnulib.
+  case $host_os,$HAVE_OPENDIR in
+    os2*,1)
+      REPLACE_OPENDIR=1;;
+  esac
+])
diff --git a/m4/pathmax.m4 b/m4/pathmax.m4
new file mode 100644
index 0000000..bb4fdeb
--- /dev/null
+++ b/m4/pathmax.m4
@@ -0,0 +1,42 @@
+# pathmax.m4 serial 11
+dnl Copyright (C) 2002-2003, 2005-2006, 2009-2020 Free Software Foundation,
+dnl Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_PATHMAX],
+[
+  dnl Prerequisites of lib/pathmax.h.
+  AC_CHECK_HEADERS_ONCE([sys/param.h])
+])
+
+# Expands to a piece of C program that defines PATH_MAX in the same way as
+# "pathmax.h" will do.
+AC_DEFUN([gl_PATHMAX_SNIPPET], [[
+/* Arrange to define PATH_MAX, like "pathmax.h" does. */
+#if HAVE_UNISTD_H
+# include <unistd.h>
+#endif
+#include <limits.h>
+#if defined HAVE_SYS_PARAM_H && !defined PATH_MAX && !defined MAXPATHLEN
+# include <sys/param.h>
+#endif
+#if !defined PATH_MAX && defined MAXPATHLEN
+# define PATH_MAX MAXPATHLEN
+#endif
+#ifdef __hpux
+# undef PATH_MAX
+# define PATH_MAX 1024
+#endif
+#if defined _WIN32 && ! defined __CYGWIN__
+# undef PATH_MAX
+# define PATH_MAX 260
+#endif
+]])
+
+# Prerequisites of gl_PATHMAX_SNIPPET.
+AC_DEFUN([gl_PATHMAX_SNIPPET_PREREQ],
+[
+  AC_CHECK_HEADERS_ONCE([unistd.h sys/param.h])
+])
diff --git a/m4/pipe.m4 b/m4/pipe.m4
new file mode 100644
index 0000000..6b1fa2f
--- /dev/null
+++ b/m4/pipe.m4
@@ -0,0 +1,15 @@
+# pipe.m4 serial 2
+dnl Copyright (C) 2010-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_PIPE],
+[
+  AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
+
+  AC_CHECK_FUNCS_ONCE([pipe])
+  if test $ac_cv_func_pipe != yes; then
+    HAVE_PIPE=0
+  fi
+])
diff --git a/m4/pipe2.m4 b/m4/pipe2.m4
new file mode 100644
index 0000000..d36821e
--- /dev/null
+++ b/m4/pipe2.m4
@@ -0,0 +1,18 @@
+# pipe2.m4 serial 2
+dnl Copyright (C) 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_PIPE2],
+[
+  AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
+
+  dnl Persuade glibc <unistd.h> to declare pipe2().
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
+
+  AC_CHECK_FUNCS_ONCE([pipe2])
+  if test $ac_cv_func_pipe2 != yes; then
+    HAVE_PIPE2=0
+  fi
+])
diff --git a/m4/po.m4 b/m4/po.m4
new file mode 100644
index 0000000..84659ea
--- /dev/null
+++ b/m4/po.m4
@@ -0,0 +1,453 @@
+# po.m4 serial 22 (gettext-0.19)
+dnl Copyright (C) 1995-2014 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+dnl
+dnl This file can can be used in projects which are not available under
+dnl the GNU General Public License or the GNU Library General Public
+dnl License but which still want to provide support for the GNU gettext
+dnl functionality.
+dnl Please note that the actual code of the GNU gettext library is covered
+dnl by the GNU Library General Public License, and the rest of the GNU
+dnl gettext package package is covered by the GNU General Public License.
+dnl They are *not* in the public domain.
+
+dnl Authors:
+dnl   Ulrich Drepper <drepper@cygnus.com>, 1995-2000.
+dnl   Bruno Haible <haible@clisp.cons.org>, 2000-2003.
+
+AC_PREREQ([2.60])
+
+dnl Checks for all prerequisites of the po subdirectory.
+AC_DEFUN([AM_PO_SUBDIRS],
+[
+  AC_REQUIRE([AC_PROG_MAKE_SET])dnl
+  AC_REQUIRE([AC_PROG_INSTALL])dnl
+  AC_REQUIRE([AC_PROG_MKDIR_P])dnl
+  AC_REQUIRE([AC_PROG_SED])dnl
+  AC_REQUIRE([AM_NLS])dnl
+
+  dnl Release version of the gettext macros. This is used to ensure that
+  dnl the gettext macros and po/Makefile.in.in are in sync.
+  AC_SUBST([GETTEXT_MACRO_VERSION], [0.19])
+
+  dnl Perform the following tests also if --disable-nls has been given,
+  dnl because they are needed for "make dist" to work.
+
+  dnl Search for GNU msgfmt in the PATH.
+  dnl The first test excludes Solaris msgfmt and early GNU msgfmt versions.
+  dnl The second test excludes FreeBSD msgfmt.
+  AM_PATH_PROG_WITH_TEST(MSGFMT, msgfmt,
+    [$ac_dir/$ac_word --statistics /dev/null >&]AS_MESSAGE_LOG_FD[ 2>&1 &&
+     (if $ac_dir/$ac_word --statistics /dev/null 2>&1 >/dev/null | grep usage >/dev/null; then exit 1; else exit 0; fi)],
+    :)
+  AC_PATH_PROG([GMSGFMT], [gmsgfmt], [$MSGFMT])
+
+  dnl Test whether it is GNU msgfmt >= 0.15.
+changequote(,)dnl
+  case `$MSGFMT --version | sed 1q | sed -e 's,^[^0-9]*,,'` in
+    '' | 0.[0-9] | 0.[0-9].* | 0.1[0-4] | 0.1[0-4].*) MSGFMT_015=: ;;
+    *) MSGFMT_015=$MSGFMT ;;
+  esac
+changequote([,])dnl
+  AC_SUBST([MSGFMT_015])
+changequote(,)dnl
+  case `$GMSGFMT --version | sed 1q | sed -e 's,^[^0-9]*,,'` in
+    '' | 0.[0-9] | 0.[0-9].* | 0.1[0-4] | 0.1[0-4].*) GMSGFMT_015=: ;;
+    *) GMSGFMT_015=$GMSGFMT ;;
+  esac
+changequote([,])dnl
+  AC_SUBST([GMSGFMT_015])
+
+  dnl Search for GNU xgettext 0.12 or newer in the PATH.
+  dnl The first test excludes Solaris xgettext and early GNU xgettext versions.
+  dnl The second test excludes FreeBSD xgettext.
+  AM_PATH_PROG_WITH_TEST(XGETTEXT, xgettext,
+    [$ac_dir/$ac_word --omit-header --copyright-holder= --msgid-bugs-address= /dev/null >&]AS_MESSAGE_LOG_FD[ 2>&1 &&
+     (if $ac_dir/$ac_word --omit-header --copyright-holder= --msgid-bugs-address= /dev/null 2>&1 >/dev/null | grep usage >/dev/null; then exit 1; else exit 0; fi)],
+    :)
+  dnl Remove leftover from FreeBSD xgettext call.
+  rm -f messages.po
+
+  dnl Test whether it is GNU xgettext >= 0.15.
+changequote(,)dnl
+  case `$XGETTEXT --version | sed 1q | sed -e 's,^[^0-9]*,,'` in
+    '' | 0.[0-9] | 0.[0-9].* | 0.1[0-4] | 0.1[0-4].*) XGETTEXT_015=: ;;
+    *) XGETTEXT_015=$XGETTEXT ;;
+  esac
+changequote([,])dnl
+  AC_SUBST([XGETTEXT_015])
+
+  dnl Search for GNU msgmerge 0.11 or newer in the PATH.
+  AM_PATH_PROG_WITH_TEST(MSGMERGE, msgmerge,
+    [$ac_dir/$ac_word --update -q /dev/null /dev/null >&]AS_MESSAGE_LOG_FD[ 2>&1], :)
+
+  dnl Installation directories.
+  dnl Autoconf >= 2.60 defines localedir. For older versions of autoconf, we
+  dnl have to define it here, so that it can be used in po/Makefile.
+  test -n "$localedir" || localedir='${datadir}/locale'
+  AC_SUBST([localedir])
+
+  dnl Support for AM_XGETTEXT_OPTION.
+  test -n "${XGETTEXT_EXTRA_OPTIONS+set}" || XGETTEXT_EXTRA_OPTIONS=
+  AC_SUBST([XGETTEXT_EXTRA_OPTIONS])
+
+  AC_CONFIG_COMMANDS([po-directories], [[
+    for ac_file in $CONFIG_FILES; do
+      # Support "outfile[:infile[:infile...]]"
+      case "$ac_file" in
+        *:*) ac_file=`echo "$ac_file"|sed 's%:.*%%'` ;;
+      esac
+      # PO directories have a Makefile.in generated from Makefile.in.in.
+      case "$ac_file" in */Makefile.in)
+        # Adjust a relative srcdir.
+        ac_dir=`echo "$ac_file"|sed 's%/[^/][^/]*$%%'`
+        ac_dir_suffix=/`echo "$ac_dir"|sed 's%^\./%%'`
+        ac_dots=`echo "$ac_dir_suffix"|sed 's%/[^/]*%../%g'`
+        # In autoconf-2.13 it is called $ac_given_srcdir.
+        # In autoconf-2.50 it is called $srcdir.
+        test -n "$ac_given_srcdir" || ac_given_srcdir="$srcdir"
+        case "$ac_given_srcdir" in
+          .)  top_srcdir=`echo $ac_dots|sed 's%/$%%'` ;;
+          /*) top_srcdir="$ac_given_srcdir" ;;
+          *)  top_srcdir="$ac_dots$ac_given_srcdir" ;;
+        esac
+        # Treat a directory as a PO directory if and only if it has a
+        # POTFILES.in file. This allows packages to have multiple PO
+        # directories under different names or in different locations.
+        if test -f "$ac_given_srcdir/$ac_dir/POTFILES.in"; then
+          rm -f "$ac_dir/POTFILES"
+          test -n "$as_me" && echo "$as_me: creating $ac_dir/POTFILES" || echo "creating $ac_dir/POTFILES"
+          gt_tab=`printf '\t'`
+          cat "$ac_given_srcdir/$ac_dir/POTFILES.in" | sed -e "/^#/d" -e "/^[ ${gt_tab}]*\$/d" -e "s,.*,     $top_srcdir/& \\\\," | sed -e "\$s/\(.*\) \\\\/\1/" > "$ac_dir/POTFILES"
+          POMAKEFILEDEPS="POTFILES.in"
+          # ALL_LINGUAS, POFILES, UPDATEPOFILES, DUMMYPOFILES, GMOFILES depend
+          # on $ac_dir but don't depend on user-specified configuration
+          # parameters.
+          if test -f "$ac_given_srcdir/$ac_dir/LINGUAS"; then
+            # The LINGUAS file contains the set of available languages.
+            if test -n "$OBSOLETE_ALL_LINGUAS"; then
+              test -n "$as_me" && echo "$as_me: setting ALL_LINGUAS in configure.in is obsolete" || echo "setting ALL_LINGUAS in configure.in is obsolete"
+            fi
+            ALL_LINGUAS_=`sed -e "/^#/d" -e "s/#.*//" "$ac_given_srcdir/$ac_dir/LINGUAS"`
+            # Hide the ALL_LINGUAS assignment from automake < 1.5.
+            eval 'ALL_LINGUAS''=$ALL_LINGUAS_'
+            POMAKEFILEDEPS="$POMAKEFILEDEPS LINGUAS"
+          else
+            # The set of available languages was given in configure.in.
+            # Hide the ALL_LINGUAS assignment from automake < 1.5.
+            eval 'ALL_LINGUAS''=$OBSOLETE_ALL_LINGUAS'
+          fi
+          # Compute POFILES
+          # as      $(foreach lang, $(ALL_LINGUAS), $(srcdir)/$(lang).po)
+          # Compute UPDATEPOFILES
+          # as      $(foreach lang, $(ALL_LINGUAS), $(lang).po-update)
+          # Compute DUMMYPOFILES
+          # as      $(foreach lang, $(ALL_LINGUAS), $(lang).nop)
+          # Compute GMOFILES
+          # as      $(foreach lang, $(ALL_LINGUAS), $(srcdir)/$(lang).gmo)
+          case "$ac_given_srcdir" in
+            .) srcdirpre= ;;
+            *) srcdirpre='$(srcdir)/' ;;
+          esac
+          POFILES=
+          UPDATEPOFILES=
+          DUMMYPOFILES=
+          GMOFILES=
+          for lang in $ALL_LINGUAS; do
+            POFILES="$POFILES $srcdirpre$lang.po"
+            UPDATEPOFILES="$UPDATEPOFILES $lang.po-update"
+            DUMMYPOFILES="$DUMMYPOFILES $lang.nop"
+            GMOFILES="$GMOFILES $srcdirpre$lang.gmo"
+          done
+          # CATALOGS depends on both $ac_dir and the user's LINGUAS
+          # environment variable.
+          INST_LINGUAS=
+          if test -n "$ALL_LINGUAS"; then
+            for presentlang in $ALL_LINGUAS; do
+              useit=no
+              if test "%UNSET%" != "$LINGUAS"; then
+                desiredlanguages="$LINGUAS"
+              else
+                desiredlanguages="$ALL_LINGUAS"
+              fi
+              for desiredlang in $desiredlanguages; do
+                # Use the presentlang catalog if desiredlang is
+                #   a. equal to presentlang, or
+                #   b. a variant of presentlang (because in this case,
+                #      presentlang can be used as a fallback for messages
+                #      which are not translated in the desiredlang catalog).
+                case "$desiredlang" in
+                  "$presentlang"*) useit=yes;;
+                esac
+              done
+              if test $useit = yes; then
+                INST_LINGUAS="$INST_LINGUAS $presentlang"
+              fi
+            done
+          fi
+          CATALOGS=
+          if test -n "$INST_LINGUAS"; then
+            for lang in $INST_LINGUAS; do
+              CATALOGS="$CATALOGS $lang.gmo"
+            done
+          fi
+          test -n "$as_me" && echo "$as_me: creating $ac_dir/Makefile" || echo "creating $ac_dir/Makefile"
+          sed -e "/^POTFILES =/r $ac_dir/POTFILES" -e "/^# Makevars/r $ac_given_srcdir/$ac_dir/Makevars" -e "s|@POFILES@|$POFILES|g" -e "s|@UPDATEPOFILES@|$UPDATEPOFILES|g" -e "s|@DUMMYPOFILES@|$DUMMYPOFILES|g" -e "s|@GMOFILES@|$GMOFILES|g" -e "s|@CATALOGS@|$CATALOGS|g" -e "s|@POMAKEFILEDEPS@|$POMAKEFILEDEPS|g" "$ac_dir/Makefile.in" > "$ac_dir/Makefile"
+          for f in "$ac_given_srcdir/$ac_dir"/Rules-*; do
+            if test -f "$f"; then
+              case "$f" in
+                *.orig | *.bak | *~) ;;
+                *) cat "$f" >> "$ac_dir/Makefile" ;;
+              esac
+            fi
+          done
+        fi
+        ;;
+      esac
+    done]],
+   [# Capture the value of obsolete ALL_LINGUAS because we need it to compute
+    # POFILES, UPDATEPOFILES, DUMMYPOFILES, GMOFILES, CATALOGS. But hide it
+    # from automake < 1.5.
+    eval 'OBSOLETE_ALL_LINGUAS''="$ALL_LINGUAS"'
+    # Capture the value of LINGUAS because we need it to compute CATALOGS.
+    LINGUAS="${LINGUAS-%UNSET%}"
+   ])
+])
+
+dnl Postprocesses a Makefile in a directory containing PO files.
+AC_DEFUN([AM_POSTPROCESS_PO_MAKEFILE],
+[
+  # When this code is run, in config.status, two variables have already been
+  # set:
+  # - OBSOLETE_ALL_LINGUAS is the value of LINGUAS set in configure.in,
+  # - LINGUAS is the value of the environment variable LINGUAS at configure
+  #   time.
+
+changequote(,)dnl
+  # Adjust a relative srcdir.
+  ac_dir=`echo "$ac_file"|sed 's%/[^/][^/]*$%%'`
+  ac_dir_suffix=/`echo "$ac_dir"|sed 's%^\./%%'`
+  ac_dots=`echo "$ac_dir_suffix"|sed 's%/[^/]*%../%g'`
+  # In autoconf-2.13 it is called $ac_given_srcdir.
+  # In autoconf-2.50 it is called $srcdir.
+  test -n "$ac_given_srcdir" || ac_given_srcdir="$srcdir"
+  case "$ac_given_srcdir" in
+    .)  top_srcdir=`echo $ac_dots|sed 's%/$%%'` ;;
+    /*) top_srcdir="$ac_given_srcdir" ;;
+    *)  top_srcdir="$ac_dots$ac_given_srcdir" ;;
+  esac
+
+  # Find a way to echo strings without interpreting backslash.
+  if test "X`(echo '\t') 2>/dev/null`" = 'X\t'; then
+    gt_echo='echo'
+  else
+    if test "X`(printf '%s\n' '\t') 2>/dev/null`" = 'X\t'; then
+      gt_echo='printf %s\n'
+    else
+      echo_func () {
+        cat <<EOT
+$*
+EOT
+      }
+      gt_echo='echo_func'
+    fi
+  fi
+
+  # A sed script that extracts the value of VARIABLE from a Makefile.
+  tab=`printf '\t'`
+  sed_x_variable='
+# Test if the hold space is empty.
+x
+s/P/P/
+x
+ta
+# Yes it was empty. Look if we have the expected variable definition.
+/^['"${tab}"' ]*VARIABLE['"${tab}"' ]*=/{
+  # Seen the first line of the variable definition.
+  s/^['"${tab}"' ]*VARIABLE['"${tab}"' ]*=//
+  ba
+}
+bd
+:a
+# Here we are processing a line from the variable definition.
+# Remove comment, more precisely replace it with a space.
+s/#.*$/ /
+# See if the line ends in a backslash.
+tb
+:b
+s/\\$//
+# Print the line, without the trailing backslash.
+p
+tc
+# There was no trailing backslash. The end of the variable definition is
+# reached. Clear the hold space.
+s/^.*$//
+x
+bd
+:c
+# A trailing backslash means that the variable definition continues in the
+# next line. Put a nonempty string into the hold space to indicate this.
+s/^.*$/P/
+x
+:d
+'
+changequote([,])dnl
+
+  # Set POTFILES to the value of the Makefile variable POTFILES.
+  sed_x_POTFILES=`$gt_echo "$sed_x_variable" | sed -e '/^ *#/d' -e 's/VARIABLE/POTFILES/g'`
+  POTFILES=`sed -n -e "$sed_x_POTFILES" < "$ac_file"`
+  # Compute POTFILES_DEPS as
+  #   $(foreach file, $(POTFILES), $(top_srcdir)/$(file))
+  POTFILES_DEPS=
+  for file in $POTFILES; do
+    POTFILES_DEPS="$POTFILES_DEPS "'$(top_srcdir)/'"$file"
+  done
+  POMAKEFILEDEPS=""
+
+  if test -n "$OBSOLETE_ALL_LINGUAS"; then
+    test -n "$as_me" && echo "$as_me: setting ALL_LINGUAS in configure.in is obsolete" || echo "setting ALL_LINGUAS in configure.in is obsolete"
+  fi
+  if test -f "$ac_given_srcdir/$ac_dir/LINGUAS"; then
+    # The LINGUAS file contains the set of available languages.
+    ALL_LINGUAS_=`sed -e "/^#/d" -e "s/#.*//" "$ac_given_srcdir/$ac_dir/LINGUAS"`
+    POMAKEFILEDEPS="$POMAKEFILEDEPS LINGUAS"
+  else
+    # Set ALL_LINGUAS to the value of the Makefile variable LINGUAS.
+    sed_x_LINGUAS=`$gt_echo "$sed_x_variable" | sed -e '/^ *#/d' -e 's/VARIABLE/LINGUAS/g'`
+    ALL_LINGUAS_=`sed -n -e "$sed_x_LINGUAS" < "$ac_file"`
+  fi
+  # Hide the ALL_LINGUAS assignment from automake < 1.5.
+  eval 'ALL_LINGUAS''=$ALL_LINGUAS_'
+  # Compute POFILES
+  # as      $(foreach lang, $(ALL_LINGUAS), $(srcdir)/$(lang).po)
+  # Compute UPDATEPOFILES
+  # as      $(foreach lang, $(ALL_LINGUAS), $(lang).po-update)
+  # Compute DUMMYPOFILES
+  # as      $(foreach lang, $(ALL_LINGUAS), $(lang).nop)
+  # Compute GMOFILES
+  # as      $(foreach lang, $(ALL_LINGUAS), $(srcdir)/$(lang).gmo)
+  # Compute PROPERTIESFILES
+  # as      $(foreach lang, $(ALL_LINGUAS), $(top_srcdir)/$(DOMAIN)_$(lang).properties)
+  # Compute CLASSFILES
+  # as      $(foreach lang, $(ALL_LINGUAS), $(top_srcdir)/$(DOMAIN)_$(lang).class)
+  # Compute QMFILES
+  # as      $(foreach lang, $(ALL_LINGUAS), $(srcdir)/$(lang).qm)
+  # Compute MSGFILES
+  # as      $(foreach lang, $(ALL_LINGUAS), $(srcdir)/$(frob $(lang)).msg)
+  # Compute RESOURCESDLLFILES
+  # as      $(foreach lang, $(ALL_LINGUAS), $(srcdir)/$(frob $(lang))/$(DOMAIN).resources.dll)
+  case "$ac_given_srcdir" in
+    .) srcdirpre= ;;
+    *) srcdirpre='$(srcdir)/' ;;
+  esac
+  POFILES=
+  UPDATEPOFILES=
+  DUMMYPOFILES=
+  GMOFILES=
+  PROPERTIESFILES=
+  CLASSFILES=
+  QMFILES=
+  MSGFILES=
+  RESOURCESDLLFILES=
+  for lang in $ALL_LINGUAS; do
+    POFILES="$POFILES $srcdirpre$lang.po"
+    UPDATEPOFILES="$UPDATEPOFILES $lang.po-update"
+    DUMMYPOFILES="$DUMMYPOFILES $lang.nop"
+    GMOFILES="$GMOFILES $srcdirpre$lang.gmo"
+    PROPERTIESFILES="$PROPERTIESFILES \$(top_srcdir)/\$(DOMAIN)_$lang.properties"
+    CLASSFILES="$CLASSFILES \$(top_srcdir)/\$(DOMAIN)_$lang.class"
+    QMFILES="$QMFILES $srcdirpre$lang.qm"
+    frobbedlang=`echo $lang | sed -e 's/\..*$//' -e 'y/ABCDEFGHIJKLMNOPQRSTUVWXYZ/abcdefghijklmnopqrstuvwxyz/'`
+    MSGFILES="$MSGFILES $srcdirpre$frobbedlang.msg"
+    frobbedlang=`echo $lang | sed -e 's/_/-/g' -e 's/^sr-CS/sr-SP/' -e 's/@latin$/-Latn/' -e 's/@cyrillic$/-Cyrl/' -e 's/^sr-SP$/sr-SP-Latn/' -e 's/^uz-UZ$/uz-UZ-Latn/'`
+    RESOURCESDLLFILES="$RESOURCESDLLFILES $srcdirpre$frobbedlang/\$(DOMAIN).resources.dll"
+  done
+  # CATALOGS depends on both $ac_dir and the user's LINGUAS
+  # environment variable.
+  INST_LINGUAS=
+  if test -n "$ALL_LINGUAS"; then
+    for presentlang in $ALL_LINGUAS; do
+      useit=no
+      if test "%UNSET%" != "$LINGUAS"; then
+        desiredlanguages="$LINGUAS"
+      else
+        desiredlanguages="$ALL_LINGUAS"
+      fi
+      for desiredlang in $desiredlanguages; do
+        # Use the presentlang catalog if desiredlang is
+        #   a. equal to presentlang, or
+        #   b. a variant of presentlang (because in this case,
+        #      presentlang can be used as a fallback for messages
+        #      which are not translated in the desiredlang catalog).
+        case "$desiredlang" in
+          "$presentlang"*) useit=yes;;
+        esac
+      done
+      if test $useit = yes; then
+        INST_LINGUAS="$INST_LINGUAS $presentlang"
+      fi
+    done
+  fi
+  CATALOGS=
+  JAVACATALOGS=
+  QTCATALOGS=
+  TCLCATALOGS=
+  CSHARPCATALOGS=
+  if test -n "$INST_LINGUAS"; then
+    for lang in $INST_LINGUAS; do
+      CATALOGS="$CATALOGS $lang.gmo"
+      JAVACATALOGS="$JAVACATALOGS \$(DOMAIN)_$lang.properties"
+      QTCATALOGS="$QTCATALOGS $lang.qm"
+      frobbedlang=`echo $lang | sed -e 's/\..*$//' -e 'y/ABCDEFGHIJKLMNOPQRSTUVWXYZ/abcdefghijklmnopqrstuvwxyz/'`
+      TCLCATALOGS="$TCLCATALOGS $frobbedlang.msg"
+      frobbedlang=`echo $lang | sed -e 's/_/-/g' -e 's/^sr-CS/sr-SP/' -e 's/@latin$/-Latn/' -e 's/@cyrillic$/-Cyrl/' -e 's/^sr-SP$/sr-SP-Latn/' -e 's/^uz-UZ$/uz-UZ-Latn/'`
+      CSHARPCATALOGS="$CSHARPCATALOGS $frobbedlang/\$(DOMAIN).resources.dll"
+    done
+  fi
+
+  sed -e "s|@POTFILES_DEPS@|$POTFILES_DEPS|g" -e "s|@POFILES@|$POFILES|g" -e "s|@UPDATEPOFILES@|$UPDATEPOFILES|g" -e "s|@DUMMYPOFILES@|$DUMMYPOFILES|g" -e "s|@GMOFILES@|$GMOFILES|g" -e "s|@PROPERTIESFILES@|$PROPERTIESFILES|g" -e "s|@CLASSFILES@|$CLASSFILES|g" -e "s|@QMFILES@|$QMFILES|g" -e "s|@MSGFILES@|$MSGFILES|g" -e "s|@RESOURCESDLLFILES@|$RESOURCESDLLFILES|g" -e "s|@CATALOGS@|$CATALOGS|g" -e "s|@JAVACATALOGS@|$JAVACATALOGS|g" -e "s|@QTCATALOGS@|$QTCATALOGS|g" -e "s|@TCLCATALOGS@|$TCLCATALOGS|g" -e "s|@CSHARPCATALOGS@|$CSHARPCATALOGS|g" -e 's,^#distdir:,distdir:,' < "$ac_file" > "$ac_file.tmp"
+  tab=`printf '\t'`
+  if grep -l '@TCLCATALOGS@' "$ac_file" > /dev/null; then
+    # Add dependencies that cannot be formulated as a simple suffix rule.
+    for lang in $ALL_LINGUAS; do
+      frobbedlang=`echo $lang | sed -e 's/\..*$//' -e 'y/ABCDEFGHIJKLMNOPQRSTUVWXYZ/abcdefghijklmnopqrstuvwxyz/'`
+      cat >> "$ac_file.tmp" <<EOF
+$frobbedlang.msg: $lang.po
+${tab}@echo "\$(MSGFMT) -c --tcl -d \$(srcdir) -l $lang $srcdirpre$lang.po"; \
+${tab}\$(MSGFMT) -c --tcl -d "\$(srcdir)" -l $lang $srcdirpre$lang.po || { rm -f "\$(srcdir)/$frobbedlang.msg"; exit 1; }
+EOF
+    done
+  fi
+  if grep -l '@CSHARPCATALOGS@' "$ac_file" > /dev/null; then
+    # Add dependencies that cannot be formulated as a simple suffix rule.
+    for lang in $ALL_LINGUAS; do
+      frobbedlang=`echo $lang | sed -e 's/_/-/g' -e 's/^sr-CS/sr-SP/' -e 's/@latin$/-Latn/' -e 's/@cyrillic$/-Cyrl/' -e 's/^sr-SP$/sr-SP-Latn/' -e 's/^uz-UZ$/uz-UZ-Latn/'`
+      cat >> "$ac_file.tmp" <<EOF
+$frobbedlang/\$(DOMAIN).resources.dll: $lang.po
+${tab}@echo "\$(MSGFMT) -c --csharp -d \$(srcdir) -l $lang $srcdirpre$lang.po -r \$(DOMAIN)"; \
+${tab}\$(MSGFMT) -c --csharp -d "\$(srcdir)" -l $lang $srcdirpre$lang.po -r "\$(DOMAIN)" || { rm -f "\$(srcdir)/$frobbedlang.msg"; exit 1; }
+EOF
+    done
+  fi
+  if test -n "$POMAKEFILEDEPS"; then
+    cat >> "$ac_file.tmp" <<EOF
+Makefile: $POMAKEFILEDEPS
+EOF
+  fi
+  mv "$ac_file.tmp" "$ac_file"
+])
+
+dnl Initializes the accumulator used by AM_XGETTEXT_OPTION.
+AC_DEFUN([AM_XGETTEXT_OPTION_INIT],
+[
+  XGETTEXT_EXTRA_OPTIONS=
+])
+
+dnl Registers an option to be passed to xgettext in the po subdirectory.
+AC_DEFUN([AM_XGETTEXT_OPTION],
+[
+  AC_REQUIRE([AM_XGETTEXT_OPTION_INIT])
+  XGETTEXT_EXTRA_OPTIONS="$XGETTEXT_EXTRA_OPTIONS $1"
+])
diff --git a/m4/posix_spawn.m4 b/m4/posix_spawn.m4
new file mode 100644
index 0000000..59e56fc
--- /dev/null
+++ b/m4/posix_spawn.m4
@@ -0,0 +1,678 @@
+# posix_spawn.m4 serial 19
+dnl Copyright (C) 2008-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl Tests whether the entire posix_spawn facility is available.
+AC_DEFUN([gl_POSIX_SPAWN],
+[
+  AC_REQUIRE([gl_POSIX_SPAWN_BODY])
+])
+
+AC_DEFUN([gl_POSIX_SPAWN_BODY],
+[
+  AC_REQUIRE([gl_SPAWN_H_DEFAULTS])
+  AC_REQUIRE([gl_HAVE_POSIX_SPAWN])
+  dnl Assume that when the main function exists, all the others,
+  dnl except posix_spawnattr_{get,set}sched*, are available as well.
+  dnl AC_CHECK_FUNCS_ONCE([posix_spawnp])
+  dnl AC_CHECK_FUNCS_ONCE([posix_spawn_file_actions_init])
+  dnl AC_CHECK_FUNCS_ONCE([posix_spawn_file_actions_addclose])
+  dnl AC_CHECK_FUNCS_ONCE([posix_spawn_file_actions_adddup2])
+  dnl AC_CHECK_FUNCS_ONCE([posix_spawn_file_actions_addopen])
+  dnl AC_CHECK_FUNCS_ONCE([posix_spawn_file_actions_destroy])
+  dnl AC_CHECK_FUNCS_ONCE([posix_spawnattr_init])
+  dnl AC_CHECK_FUNCS_ONCE([posix_spawnattr_getflags])
+  dnl AC_CHECK_FUNCS_ONCE([posix_spawnattr_setflags])
+  dnl AC_CHECK_FUNCS_ONCE([posix_spawnattr_getpgroup])
+  dnl AC_CHECK_FUNCS_ONCE([posix_spawnattr_setpgroup])
+  dnl AC_CHECK_FUNCS_ONCE([posix_spawnattr_getsigdefault])
+  dnl AC_CHECK_FUNCS_ONCE([posix_spawnattr_setsigdefault])
+  dnl AC_CHECK_FUNCS_ONCE([posix_spawnattr_getsigmask])
+  dnl AC_CHECK_FUNCS_ONCE([posix_spawnattr_setsigmask])
+  dnl AC_CHECK_FUNCS_ONCE([posix_spawnattr_destroy])
+  if test $ac_cv_func_posix_spawn = yes; then
+    m4_ifdef([gl_FUNC_POSIX_SPAWN_FILE_ACTIONS_ADDCHDIR],
+      [dnl Module 'posix_spawn_file_actions_addchdir' is present.
+       AC_CHECK_FUNCS_ONCE([posix_spawn_file_actions_addchdir_np])
+       if test $ac_cv_func_posix_spawn_file_actions_addchdir_np = no; then
+         dnl In order to implement the posix_spawn_file_actions_addchdir
+         dnl function, we need to replace the entire posix_spawn facility.
+         REPLACE_POSIX_SPAWN=1
+       fi
+      ])
+    m4_ifdef([gl_FUNC_POSIX_SPAWN_FILE_ACTIONS_ADDFCHDIR],
+      [dnl Module 'posix_spawn_file_actions_addfchdir' is present.
+       AC_CHECK_FUNCS_ONCE([posix_spawn_file_actions_addfchdir_np])
+       if test $ac_cv_func_posix_spawn_file_actions_addfchdir_np = no; then
+         dnl In order to implement the posix_spawn_file_actions_addfchdir
+         dnl function, we need to replace the entire posix_spawn facility.
+         REPLACE_POSIX_SPAWN=1
+       fi
+      ])
+    if test $REPLACE_POSIX_SPAWN = 0; then
+      gl_POSIX_SPAWN_WORKS
+      case "$gl_cv_func_posix_spawn_works" in
+        *yes) ;;
+        *) REPLACE_POSIX_SPAWN=1 ;;
+      esac
+    fi
+    if test $REPLACE_POSIX_SPAWN = 0; then
+      gl_POSIX_SPAWN_SECURE
+      case "$gl_cv_func_posix_spawn_secure_exec" in
+        *yes) ;;
+        *) REPLACE_POSIX_SPAWN=1 ;;
+      esac
+      case "$gl_cv_func_posix_spawnp_secure_exec" in
+        *yes) ;;
+        *) REPLACE_POSIX_SPAWN=1 ;;
+      esac
+    fi
+    if test $REPLACE_POSIX_SPAWN = 0; then
+      dnl Assume that these functions are available if POSIX_SPAWN_SETSCHEDULER
+      dnl evaluates to nonzero.
+      dnl AC_CHECK_FUNCS_ONCE([posix_spawnattr_getschedpolicy])
+      dnl AC_CHECK_FUNCS_ONCE([posix_spawnattr_setschedpolicy])
+      AC_CACHE_CHECK([whether posix_spawnattr_setschedpolicy is supported],
+        [gl_cv_func_spawnattr_setschedpolicy],
+        [AC_EGREP_CPP([POSIX scheduling supported], [
+#include <spawn.h>
+#if POSIX_SPAWN_SETSCHEDULER
+ POSIX scheduling supported
+#endif
+],
+           [gl_cv_func_spawnattr_setschedpolicy=yes],
+           [gl_cv_func_spawnattr_setschedpolicy=no])
+        ])
+      dnl Assume that these functions are available if POSIX_SPAWN_SETSCHEDPARAM
+      dnl evaluates to nonzero.
+      dnl AC_CHECK_FUNCS_ONCE([posix_spawnattr_getschedparam])
+      dnl AC_CHECK_FUNCS_ONCE([posix_spawnattr_setschedparam])
+      AC_CACHE_CHECK([whether posix_spawnattr_setschedparam is supported],
+        [gl_cv_func_spawnattr_setschedparam],
+        [AC_EGREP_CPP([POSIX scheduling supported], [
+#include <spawn.h>
+#if POSIX_SPAWN_SETSCHEDPARAM
+ POSIX scheduling supported
+#endif
+],
+           [gl_cv_func_spawnattr_setschedparam=yes],
+           [gl_cv_func_spawnattr_setschedparam=no])
+        ])
+    fi
+  fi
+  if test $ac_cv_func_posix_spawn != yes || test $REPLACE_POSIX_SPAWN = 1; then
+    AC_DEFINE([REPLACE_POSIX_SPAWN], [1],
+      [Define if gnulib uses its own posix_spawn and posix_spawnp functions.])
+  fi
+])
+
+dnl Test whether posix_spawn actually works.
+dnl posix_spawn on AIX 5.3..6.1 has two bugs:
+dnl 1) When it fails to execute the program, the child process exits with
+dnl    exit() rather than _exit(), which causes the stdio buffers to be
+dnl    flushed. Reported by Rainer Tammer.
+dnl 2) The posix_spawn_file_actions_addopen function does not support file
+dnl    names that contain a '*'.
+dnl posix_spawn on AIX 5.3..6.1 has also a third bug: It does not work
+dnl when POSIX threads are used. But we don't test against this bug here.
+AC_DEFUN([gl_POSIX_SPAWN_WORKS],
+[
+  AC_REQUIRE([AC_PROG_CC])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_CACHE_CHECK([whether posix_spawn works], [gl_cv_func_posix_spawn_works],
+    [if test $cross_compiling = no; then
+       AC_LINK_IFELSE([AC_LANG_SOURCE([[
+#include <errno.h>
+#include <fcntl.h>
+#include <signal.h>
+#include <spawn.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+]GL_MDA_DEFINES[
+
+extern char **environ;
+
+#ifndef STDIN_FILENO
+# define STDIN_FILENO 0
+#endif
+#ifndef STDOUT_FILENO
+# define STDOUT_FILENO 1
+#endif
+#ifndef STDERR_FILENO
+# define STDERR_FILENO 2
+#endif
+
+#ifndef WTERMSIG
+# define WTERMSIG(x) ((x) & 0x7f)
+#endif
+#ifndef WIFEXITED
+# define WIFEXITED(x) (WTERMSIG (x) == 0)
+#endif
+#ifndef WEXITSTATUS
+# define WEXITSTATUS(x) (((x) >> 8) & 0xff)
+#endif
+
+#define CHILD_PROGRAM_FILENAME "/non/exist/ent"
+
+static int
+fd_safer (int fd)
+{
+  if (0 <= fd && fd <= 2)
+    {
+      int f = fd_safer (dup (fd));
+      int e = errno;
+      close (fd);
+      errno = e;
+      fd = f;
+    }
+
+  return fd;
+}
+
+int
+main ()
+{
+  char *argv[2] = { CHILD_PROGRAM_FILENAME, NULL };
+  int ofd[2];
+  sigset_t blocked_signals;
+  sigset_t fatal_signal_set;
+  posix_spawn_file_actions_t actions;
+  bool actions_allocated;
+  posix_spawnattr_t attrs;
+  bool attrs_allocated;
+  int err;
+  pid_t child;
+  int status;
+  int exitstatus;
+
+  setvbuf (stdout, NULL, _IOFBF, 0);
+  puts ("This should be seen only once.");
+  if (pipe (ofd) < 0 || (ofd[1] = fd_safer (ofd[1])) < 0)
+    {
+      perror ("cannot create pipe");
+      exit (1);
+    }
+  sigprocmask (SIG_SETMASK, NULL, &blocked_signals);
+  sigemptyset (&fatal_signal_set);
+  sigaddset (&fatal_signal_set, SIGINT);
+  sigaddset (&fatal_signal_set, SIGTERM);
+  sigaddset (&fatal_signal_set, SIGHUP);
+  sigaddset (&fatal_signal_set, SIGPIPE);
+  sigprocmask (SIG_BLOCK, &fatal_signal_set, NULL);
+  actions_allocated = false;
+  attrs_allocated = false;
+  if ((err = posix_spawn_file_actions_init (&actions)) != 0
+      || (actions_allocated = true,
+          (err = posix_spawn_file_actions_adddup2 (&actions, ofd[0], STDIN_FILENO)) != 0
+          || (err = posix_spawn_file_actions_addclose (&actions, ofd[0])) != 0
+          || (err = posix_spawn_file_actions_addclose (&actions, ofd[1])) != 0
+          || (err = posix_spawnattr_init (&attrs)) != 0
+          || (attrs_allocated = true,
+              (err = posix_spawnattr_setsigmask (&attrs, &blocked_signals)) != 0
+              || (err = posix_spawnattr_setflags (&attrs, POSIX_SPAWN_SETSIGMASK)) != 0)
+          || (err = posix_spawnp (&child, CHILD_PROGRAM_FILENAME, &actions, &attrs, argv, environ)) != 0))
+    {
+      if (actions_allocated)
+        posix_spawn_file_actions_destroy (&actions);
+      if (attrs_allocated)
+        posix_spawnattr_destroy (&attrs);
+      sigprocmask (SIG_UNBLOCK, &fatal_signal_set, NULL);
+      if (err == ENOENT)
+        return 0;
+      else
+        {
+          errno = err;
+          perror ("subprocess failed");
+          exit (1);
+        }
+    }
+  posix_spawn_file_actions_destroy (&actions);
+  posix_spawnattr_destroy (&attrs);
+  sigprocmask (SIG_UNBLOCK, &fatal_signal_set, NULL);
+  close (ofd[0]);
+  close (ofd[1]);
+  status = 0;
+  while (waitpid (child, &status, 0) != child)
+    ;
+  if (!WIFEXITED (status))
+    {
+      fprintf (stderr, "subprocess terminated with unexpected wait status %d\n", status);
+      exit (1);
+    }
+  exitstatus = WEXITSTATUS (status);
+  if (exitstatus != 127)
+    {
+      fprintf (stderr, "subprocess terminated with unexpected exit status %d\n", exitstatus);
+      exit (1);
+    }
+  return 0;
+}
+]])],
+         [if test -s conftest$ac_exeext \
+             && ./conftest$ac_exeext > conftest.out \
+             && echo 'This should be seen only once.' > conftest.ok \
+             && cmp conftest.out conftest.ok >/dev/null 2>&1; then
+            gl_cv_func_posix_spawn_works=yes
+          else
+            gl_cv_func_posix_spawn_works=no
+          fi],
+         [gl_cv_func_posix_spawn_works=no])
+       if test $gl_cv_func_posix_spawn_works = yes; then
+         AC_RUN_IFELSE([AC_LANG_SOURCE([[
+/* Test whether posix_spawn_file_actions_addopen supports filename arguments
+   that contain special characters such as '*'.  */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <signal.h>
+#include <spawn.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+]GL_MDA_DEFINES[
+
+extern char **environ;
+
+#ifndef STDIN_FILENO
+# define STDIN_FILENO 0
+#endif
+#ifndef STDOUT_FILENO
+# define STDOUT_FILENO 1
+#endif
+#ifndef STDERR_FILENO
+# define STDERR_FILENO 2
+#endif
+
+#ifndef WTERMSIG
+# define WTERMSIG(x) ((x) & 0x7f)
+#endif
+#ifndef WIFEXITED
+# define WIFEXITED(x) (WTERMSIG (x) == 0)
+#endif
+#ifndef WEXITSTATUS
+# define WEXITSTATUS(x) (((x) >> 8) & 0xff)
+#endif
+
+#define CHILD_PROGRAM_FILENAME "conftest"
+#define DATA_FILENAME "conftest%=*#?"
+
+static int
+parent_main (void)
+{
+  FILE *fp;
+  char *argv[3] = { CHILD_PROGRAM_FILENAME, "-child", NULL };
+  posix_spawn_file_actions_t actions;
+  bool actions_allocated;
+  int err;
+  pid_t child;
+  int status;
+  int exitstatus;
+
+  /* Create a data file with specific contents.  */
+  fp = fopen (DATA_FILENAME, "wb");
+  if (fp == NULL)
+    {
+      perror ("cannot create data file");
+      return 1;
+    }
+  fwrite ("Halle Potta", 1, 11, fp);
+  if (fflush (fp) || fclose (fp))
+    {
+      perror ("cannot prepare data file");
+      return 2;
+    }
+
+  /* Avoid reading from our stdin, as it could block.  */
+  freopen ("/dev/null", "rb", stdin);
+
+  /* Test whether posix_spawn_file_actions_addopen with this file name
+     actually works, but spawning a child that reads from this file.  */
+  actions_allocated = false;
+  if ((err = posix_spawn_file_actions_init (&actions)) != 0
+      || (actions_allocated = true,
+          (err = posix_spawn_file_actions_addopen (&actions, STDIN_FILENO, DATA_FILENAME, O_RDONLY, 0600)) != 0
+          || (err = posix_spawn (&child, CHILD_PROGRAM_FILENAME, &actions, NULL, argv, environ)) != 0))
+    {
+      if (actions_allocated)
+        posix_spawn_file_actions_destroy (&actions);
+      errno = err;
+      perror ("subprocess failed");
+      return 3;
+    }
+  posix_spawn_file_actions_destroy (&actions);
+  status = 0;
+  while (waitpid (child, &status, 0) != child)
+    ;
+  if (!WIFEXITED (status))
+    {
+      fprintf (stderr, "subprocess terminated with unexpected wait status %d\n", status);
+      return 4;
+    }
+  exitstatus = WEXITSTATUS (status);
+  if (exitstatus != 0)
+    {
+      fprintf (stderr, "subprocess terminated with unexpected exit status %d\n", exitstatus);
+      return 5;
+    }
+  return 0;
+}
+
+static int
+child_main (void)
+{
+  char buf[1024];
+
+  /* See if reading from STDIN_FILENO yields the expected contents.  */
+  if (fread (buf, 1, sizeof (buf), stdin) == 11
+      && memcmp (buf, "Halle Potta", 11) == 0)
+    return 0;
+  else
+    return 8;
+}
+
+static void
+cleanup_then_die (int sig)
+{
+  /* Clean up data file.  */
+  unlink (DATA_FILENAME);
+
+  /* Re-raise the signal and die from it.  */
+  signal (sig, SIG_DFL);
+  raise (sig);
+}
+
+int
+main (int argc, char *argv[])
+{
+  int exitstatus;
+
+  if (!(argc > 1 && strcmp (argv[1], "-child") == 0))
+    {
+      /* This is the parent process.  */
+      signal (SIGINT, cleanup_then_die);
+      signal (SIGTERM, cleanup_then_die);
+      #ifdef SIGHUP
+      signal (SIGHUP, cleanup_then_die);
+      #endif
+
+      exitstatus = parent_main ();
+    }
+  else
+    {
+      /* This is the child process.  */
+
+      exitstatus = child_main ();
+    }
+  unlink (DATA_FILENAME);
+  return exitstatus;
+}
+]])],
+           [],
+           [gl_cv_func_posix_spawn_works=no])
+       fi
+     else
+       case "$host_os" in
+         aix*) gl_cv_func_posix_spawn_works="guessing no";;
+         *)    gl_cv_func_posix_spawn_works="guessing yes";;
+       esac
+     fi
+    ])
+])
+
+dnl Test whether posix_spawn and posix_spawnp are secure.
+AC_DEFUN([gl_POSIX_SPAWN_SECURE],
+[
+  AC_REQUIRE([AC_PROG_CC])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  dnl On many platforms, posix_spawn or posix_spawnp allow executing a
+  dnl script without a '#!' marker as a shell script. This is unsecure.
+  AC_CACHE_CHECK([whether posix_spawn rejects scripts without shebang],
+    [gl_cv_func_posix_spawn_secure_exec],
+    [echo ':' > conftest.scr
+     chmod a+x conftest.scr
+     AC_RUN_IFELSE([AC_LANG_SOURCE([[
+       #include <errno.h>
+       #include <spawn.h>
+       #include <stddef.h>
+       #include <sys/types.h>
+       #include <sys/wait.h>
+       int
+       main ()
+       {
+         const char *prog_path = "./conftest.scr";
+         const char *prog_argv[2] = { prog_path, NULL };
+         const char *environment[2] = { "PATH=.", NULL };
+         pid_t child;
+         int status;
+         int err = posix_spawn (&child, prog_path, NULL, NULL,
+                                (char **) prog_argv, (char **) environment);
+         if (err == ENOEXEC)
+           return 0;
+         if (err != 0)
+           return 1;
+         status = 0;
+         while (waitpid (child, &status, 0) != child)
+           ;
+         if (!WIFEXITED (status))
+           return 2;
+         if (WEXITSTATUS (status) != 127)
+           return 3;
+         return 0;
+       }
+       ]])],
+       [gl_cv_func_posix_spawn_secure_exec=yes],
+       [gl_cv_func_posix_spawn_secure_exec=no],
+       [case "$host_os" in
+          # Guess no on GNU/Hurd.
+          gnu*)
+            gl_cv_func_posix_spawn_secure_exec="guessing no" ;;
+          # Guess yes on all other platforms.
+          *)
+            gl_cv_func_posix_spawn_secure_exec="guessing yes" ;;
+        esac
+       ])
+     rm -f conftest.scr
+    ])
+  AC_CACHE_CHECK([whether posix_spawnp rejects scripts without shebang],
+    [gl_cv_func_posix_spawnp_secure_exec],
+    [echo ':' > conftest.scr
+     chmod a+x conftest.scr
+     AC_RUN_IFELSE([AC_LANG_SOURCE([[
+       #include <errno.h>
+       #include <spawn.h>
+       #include <stddef.h>
+       #include <sys/types.h>
+       #include <sys/wait.h>
+       int
+       main ()
+       {
+         const char *prog_path = "./conftest.scr";
+         const char *prog_argv[2] = { prog_path, NULL };
+         const char *environment[2] = { "PATH=.", NULL };
+         pid_t child;
+         int status;
+         int err = posix_spawnp (&child, prog_path, NULL, NULL,
+                                 (char **) prog_argv, (char **) environment);
+         if (err == ENOEXEC)
+           return 0;
+         if (err != 0)
+           return 1;
+         status = 0;
+         while (waitpid (child, &status, 0) != child)
+           ;
+         if (!WIFEXITED (status))
+           return 2;
+         if (WEXITSTATUS (status) != 127)
+           return 3;
+         return 0;
+       }
+       ]])],
+       [gl_cv_func_posix_spawnp_secure_exec=yes],
+       [gl_cv_func_posix_spawnp_secure_exec=no],
+       [case "$host_os" in
+          # Guess yes on glibc systems (glibc >= 2.15 actually) except GNU/Hurd,
+          # musl libc, NetBSD.
+          *-gnu* | *-musl* | netbsd*)
+            gl_cv_func_posix_spawnp_secure_exec="guessing yes" ;;
+          # Guess no on GNU/Hurd, macOS, FreeBSD, OpenBSD, AIX, Solaris, Cygwin.
+          gnu* | darwin* | freebsd* | dragonfly* | openbsd* | aix* | solaris* | cygwin*)
+            gl_cv_func_posix_spawnp_secure_exec="guessing no" ;;
+          # If we don't know, obey --enable-cross-guesses.
+          *)
+            gl_cv_func_posix_spawnp_secure_exec="$gl_cross_guess_normal" ;;
+        esac
+       ])
+     rm -f conftest.scr
+    ])
+])
+
+# Prerequisites of lib/spawni.c.
+AC_DEFUN([gl_PREREQ_POSIX_SPAWN_INTERNAL],
+[
+  AC_CHECK_HEADERS([paths.h])
+  AC_CHECK_FUNCS([confstr sched_setparam sched_setscheduler setegid seteuid vfork])
+])
+
+AC_DEFUN([gl_FUNC_POSIX_SPAWN_FILE_ACTIONS_ADDCLOSE],
+[
+  AC_REQUIRE([gl_SPAWN_H_DEFAULTS])
+  AC_REQUIRE([AC_PROG_CC])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  gl_POSIX_SPAWN
+  if test $REPLACE_POSIX_SPAWN = 1; then
+    REPLACE_POSIX_SPAWN_FILE_ACTIONS_ADDCLOSE=1
+  else
+    dnl On musl libc and Solaris 11.0, posix_spawn_file_actions_addclose
+    dnl succeeds even if the fd argument is out of range.
+    AC_CACHE_CHECK([whether posix_spawn_file_actions_addclose works],
+      [gl_cv_func_posix_spawn_file_actions_addclose_works],
+      [AC_RUN_IFELSE(
+         [AC_LANG_SOURCE([[
+#include <spawn.h>
+int main ()
+{
+  posix_spawn_file_actions_t actions;
+  if (posix_spawn_file_actions_init (&actions) != 0)
+    return 1;
+  if (posix_spawn_file_actions_addclose (&actions, 10000000) == 0)
+    return 2;
+  return 0;
+}]])],
+         [gl_cv_func_posix_spawn_file_actions_addclose_works=yes],
+         [gl_cv_func_posix_spawn_file_actions_addclose_works=no],
+         [# Guess no on musl libc and Solaris, yes otherwise.
+          case "$host_os" in
+            *-musl*)  gl_cv_func_posix_spawn_file_actions_addclose_works="guessing no" ;;
+            solaris*) gl_cv_func_posix_spawn_file_actions_addclose_works="guessing no" ;;
+                      # Guess no on native Windows.
+            mingw*)   gl_cv_func_posix_spawn_file_actions_addclose_works="guessing no" ;;
+            *)        gl_cv_func_posix_spawn_file_actions_addclose_works="guessing yes" ;;
+          esac
+         ])
+      ])
+    case "$gl_cv_func_posix_spawn_file_actions_addclose_works" in
+      *yes) ;;
+      *) REPLACE_POSIX_SPAWN_FILE_ACTIONS_ADDCLOSE=1 ;;
+    esac
+  fi
+])
+
+AC_DEFUN([gl_FUNC_POSIX_SPAWN_FILE_ACTIONS_ADDDUP2],
+[
+  AC_REQUIRE([gl_SPAWN_H_DEFAULTS])
+  AC_REQUIRE([AC_PROG_CC])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  gl_POSIX_SPAWN
+  if test $REPLACE_POSIX_SPAWN = 1; then
+    REPLACE_POSIX_SPAWN_FILE_ACTIONS_ADDDUP2=1
+  else
+    dnl On musl libc and Solaris 11.0, posix_spawn_file_actions_adddup2
+    dnl succeeds even if the fd argument is out of range.
+    AC_CACHE_CHECK([whether posix_spawn_file_actions_adddup2 works],
+      [gl_cv_func_posix_spawn_file_actions_adddup2_works],
+      [AC_RUN_IFELSE(
+         [AC_LANG_SOURCE([[
+#include <spawn.h>
+int main ()
+{
+  posix_spawn_file_actions_t actions;
+  if (posix_spawn_file_actions_init (&actions) != 0)
+    return 1;
+  if (posix_spawn_file_actions_adddup2 (&actions, 10000000, 2) == 0)
+    return 2;
+  return 0;
+}]])],
+         [gl_cv_func_posix_spawn_file_actions_adddup2_works=yes],
+         [gl_cv_func_posix_spawn_file_actions_adddup2_works=no],
+         [# Guess no on musl libc and Solaris, yes otherwise.
+          case "$host_os" in
+            *-musl*)  gl_cv_func_posix_spawn_file_actions_adddup2_works="guessing no";;
+            solaris*) gl_cv_func_posix_spawn_file_actions_adddup2_works="guessing no";;
+                      # Guess no on native Windows.
+            mingw*)   gl_cv_func_posix_spawn_file_actions_adddup2_works="guessing no" ;;
+            *)        gl_cv_func_posix_spawn_file_actions_adddup2_works="guessing yes";;
+          esac
+         ])
+      ])
+    case "$gl_cv_func_posix_spawn_file_actions_adddup2_works" in
+      *yes) ;;
+      *) REPLACE_POSIX_SPAWN_FILE_ACTIONS_ADDDUP2=1 ;;
+    esac
+  fi
+])
+
+AC_DEFUN([gl_FUNC_POSIX_SPAWN_FILE_ACTIONS_ADDOPEN],
+[
+  AC_REQUIRE([gl_SPAWN_H_DEFAULTS])
+  AC_REQUIRE([AC_PROG_CC])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  gl_POSIX_SPAWN
+  if test $REPLACE_POSIX_SPAWN = 1; then
+    REPLACE_POSIX_SPAWN_FILE_ACTIONS_ADDOPEN=1
+  else
+    dnl On musl libc and Solaris 11.0, posix_spawn_file_actions_addopen
+    dnl succeeds even if the fd argument is out of range.
+    AC_CACHE_CHECK([whether posix_spawn_file_actions_addopen works],
+      [gl_cv_func_posix_spawn_file_actions_addopen_works],
+      [AC_RUN_IFELSE(
+         [AC_LANG_SOURCE([[
+#include <spawn.h>
+#include <fcntl.h>
+int main ()
+{
+  posix_spawn_file_actions_t actions;
+  if (posix_spawn_file_actions_init (&actions) != 0)
+    return 1;
+  if (posix_spawn_file_actions_addopen (&actions, 10000000, "foo", 0, O_RDONLY)
+      == 0)
+    return 2;
+  return 0;
+}]])],
+         [gl_cv_func_posix_spawn_file_actions_addopen_works=yes],
+         [gl_cv_func_posix_spawn_file_actions_addopen_works=no],
+         [# Guess no on musl libc and Solaris, yes otherwise.
+          case "$host_os" in
+            *-musl*)  gl_cv_func_posix_spawn_file_actions_addopen_works="guessing no";;
+            solaris*) gl_cv_func_posix_spawn_file_actions_addopen_works="guessing no";;
+                      # Guess no on native Windows.
+            mingw*)   gl_cv_func_posix_spawn_file_actions_addopen_works="guessing no" ;;
+            *)        gl_cv_func_posix_spawn_file_actions_addopen_works="guessing yes";;
+          esac
+         ])
+      ])
+    case "$gl_cv_func_posix_spawn_file_actions_addopen_works" in
+      *yes) ;;
+      *) REPLACE_POSIX_SPAWN_FILE_ACTIONS_ADDOPEN=1 ;;
+    esac
+  fi
+])
diff --git a/m4/posix_spawn_faction_addchdir.m4 b/m4/posix_spawn_faction_addchdir.m4
new file mode 100644
index 0000000..1ce7153
--- /dev/null
+++ b/m4/posix_spawn_faction_addchdir.m4
@@ -0,0 +1,20 @@
+# posix_spawn_faction_addchdir.m4 serial 1
+dnl Copyright (C) 2018-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_POSIX_SPAWN_FILE_ACTIONS_ADDCHDIR],
+[
+  AC_REQUIRE([gl_SPAWN_H_DEFAULTS])
+  AC_REQUIRE([AC_PROG_CC])
+  gl_POSIX_SPAWN
+  AC_CHECK_FUNCS_ONCE([posix_spawn_file_actions_addchdir posix_spawn_file_actions_addchdir_np])
+  if test $ac_cv_func_posix_spawn_file_actions_addchdir = yes; then
+    dnl This function is not yet standardized. Therefore override the
+    dnl system's implementation always.
+    REPLACE_POSIX_SPAWN_FILE_ACTIONS_ADDCHDIR=1
+  else
+    HAVE_POSIX_SPAWN_FILE_ACTIONS_ADDCHDIR=0
+  fi
+])
diff --git a/m4/printf.m4 b/m4/printf.m4
new file mode 100644
index 0000000..95f7d9f
--- /dev/null
+++ b/m4/printf.m4
@@ -0,0 +1,1719 @@
+# printf.m4 serial 71
+dnl Copyright (C) 2003, 2007-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl Test whether the *printf family of functions supports the 'j', 'z', 't',
+dnl 'L' size specifiers. (ISO C99, POSIX:2001)
+dnl Result is gl_cv_func_printf_sizes_c99.
+
+AC_DEFUN([gl_PRINTF_SIZES_C99],
+[
+  AC_REQUIRE([AC_PROG_CC])
+  AC_REQUIRE([gl_AC_HEADER_STDINT_H])
+  AC_REQUIRE([gl_AC_HEADER_INTTYPES_H])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_CACHE_CHECK([whether printf supports size specifiers as in C99],
+    [gl_cv_func_printf_sizes_c99],
+    [
+      AC_RUN_IFELSE(
+        [AC_LANG_SOURCE([[
+#include <stddef.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/types.h>
+#if HAVE_STDINT_H_WITH_UINTMAX
+# include <stdint.h>
+#endif
+#if HAVE_INTTYPES_H_WITH_UINTMAX
+# include <inttypes.h>
+#endif
+static char buf[100];
+int main ()
+{
+  int result = 0;
+#if HAVE_STDINT_H_WITH_UINTMAX || HAVE_INTTYPES_H_WITH_UINTMAX
+  buf[0] = '\0';
+  if (sprintf (buf, "%ju %d", (uintmax_t) 12345671, 33, 44, 55) < 0
+      || strcmp (buf, "12345671 33") != 0)
+    result |= 1;
+#else
+  result |= 1;
+#endif
+  buf[0] = '\0';
+  if (sprintf (buf, "%zu %d", (size_t) 12345672, 33, 44, 55) < 0
+      || strcmp (buf, "12345672 33") != 0)
+    result |= 2;
+  buf[0] = '\0';
+  if (sprintf (buf, "%tu %d", (ptrdiff_t) 12345673, 33, 44, 55) < 0
+      || strcmp (buf, "12345673 33") != 0)
+    result |= 4;
+  buf[0] = '\0';
+  if (sprintf (buf, "%Lg %d", (long double) 1.5, 33, 44, 55) < 0
+      || strcmp (buf, "1.5 33") != 0)
+    result |= 8;
+  return result;
+}]])],
+        [gl_cv_func_printf_sizes_c99=yes],
+        [gl_cv_func_printf_sizes_c99=no],
+        [
+         case "$host_os" in
+changequote(,)dnl
+                                 # Guess yes on glibc systems.
+           *-gnu* | gnu*)        gl_cv_func_printf_sizes_c99="guessing yes";;
+                                 # Guess yes on musl systems.
+           *-musl*)              gl_cv_func_printf_sizes_c99="guessing yes";;
+                                 # Guess yes on FreeBSD >= 5.
+           freebsd[1-4].*)       gl_cv_func_printf_sizes_c99="guessing no";;
+           freebsd* | kfreebsd*) gl_cv_func_printf_sizes_c99="guessing yes";;
+                                 # Guess yes on Mac OS X >= 10.3.
+           darwin[1-6].*)        gl_cv_func_printf_sizes_c99="guessing no";;
+           darwin*)              gl_cv_func_printf_sizes_c99="guessing yes";;
+                                 # Guess yes on OpenBSD >= 3.9.
+           openbsd[1-2].* | openbsd3.[0-8] | openbsd3.[0-8].*)
+                                 gl_cv_func_printf_sizes_c99="guessing no";;
+           openbsd*)             gl_cv_func_printf_sizes_c99="guessing yes";;
+                                 # Guess yes on Solaris >= 2.10.
+           solaris2.[1-9][0-9]*) gl_cv_func_printf_sizes_c99="guessing yes";;
+           solaris*)             gl_cv_func_printf_sizes_c99="guessing no";;
+                                 # Guess yes on NetBSD >= 3.
+           netbsd[1-2]* | netbsdelf[1-2]* | netbsdaout[1-2]* | netbsdcoff[1-2]*)
+                                 gl_cv_func_printf_sizes_c99="guessing no";;
+           netbsd*)              gl_cv_func_printf_sizes_c99="guessing yes";;
+                                 # Guess yes on Android.
+           linux*-android*)      gl_cv_func_printf_sizes_c99="guessing yes";;
+changequote([,])dnl
+                                 # Guess yes on MSVC, no on mingw.
+           mingw*)               AC_EGREP_CPP([Known], [
+#ifdef _MSC_VER
+ Known
+#endif
+                                   ],
+                                   [gl_cv_func_printf_sizes_c99="guessing yes"],
+                                   [gl_cv_func_printf_sizes_c99="guessing no"])
+                                 ;;
+                                 # If we don't know, obey --enable-cross-guesses.
+           *)                    gl_cv_func_printf_sizes_c99="$gl_cross_guess_normal";;
+         esac
+        ])
+    ])
+])
+
+dnl Test whether the *printf family of functions supports 'long double'
+dnl arguments together with the 'L' size specifier. (ISO C99, POSIX:2001)
+dnl Result is gl_cv_func_printf_long_double.
+
+AC_DEFUN([gl_PRINTF_LONG_DOUBLE],
+[
+  AC_REQUIRE([AC_PROG_CC])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_CACHE_CHECK([whether printf supports 'long double' arguments],
+    [gl_cv_func_printf_long_double],
+    [
+      AC_RUN_IFELSE(
+        [AC_LANG_SOURCE([[
+#include <stdio.h>
+#include <string.h>
+static char buf[10000];
+int main ()
+{
+  int result = 0;
+  buf[0] = '\0';
+  if (sprintf (buf, "%Lf %d", 1.75L, 33, 44, 55) < 0
+      || strcmp (buf, "1.750000 33") != 0)
+    result |= 1;
+  buf[0] = '\0';
+  if (sprintf (buf, "%Le %d", 1.75L, 33, 44, 55) < 0
+      || strcmp (buf, "1.750000e+00 33") != 0)
+    result |= 2;
+  buf[0] = '\0';
+  if (sprintf (buf, "%Lg %d", 1.75L, 33, 44, 55) < 0
+      || strcmp (buf, "1.75 33") != 0)
+    result |= 4;
+  return result;
+}]])],
+        [gl_cv_func_printf_long_double=yes],
+        [gl_cv_func_printf_long_double=no],
+        [case "$host_os" in
+                            # Guess no on BeOS.
+           beos*)           gl_cv_func_printf_long_double="guessing no";;
+                            # Guess yes on Android.
+           linux*-android*) gl_cv_func_printf_long_double="guessing yes";;
+                            # Guess yes on MSVC, no on mingw.
+           mingw*)          AC_EGREP_CPP([Known], [
+#ifdef _MSC_VER
+ Known
+#endif
+                              ],
+                              [gl_cv_func_printf_long_double="guessing yes"],
+                              [gl_cv_func_printf_long_double="guessing no"])
+                            ;;
+           *)               gl_cv_func_printf_long_double="guessing yes";;
+         esac
+        ])
+    ])
+])
+
+dnl Test whether the *printf family of functions supports infinite and NaN
+dnl 'double' arguments and negative zero arguments in the %f, %e, %g
+dnl directives. (ISO C99, POSIX:2001)
+dnl Result is gl_cv_func_printf_infinite.
+
+AC_DEFUN([gl_PRINTF_INFINITE],
+[
+  AC_REQUIRE([AC_PROG_CC])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_CACHE_CHECK([whether printf supports infinite 'double' arguments],
+    [gl_cv_func_printf_infinite],
+    [
+      AC_RUN_IFELSE(
+        [AC_LANG_SOURCE([[
+#include <stdio.h>
+#include <string.h>
+static int
+strisnan (const char *string, size_t start_index, size_t end_index)
+{
+  if (start_index < end_index)
+    {
+      if (string[start_index] == '-')
+        start_index++;
+      if (start_index + 3 <= end_index
+          && memcmp (string + start_index, "nan", 3) == 0)
+        {
+          start_index += 3;
+          if (start_index == end_index
+              || (string[start_index] == '(' && string[end_index - 1] == ')'))
+            return 1;
+        }
+    }
+  return 0;
+}
+static int
+have_minus_zero ()
+{
+  static double plus_zero = 0.0;
+  double minus_zero = - plus_zero;
+  return memcmp (&plus_zero, &minus_zero, sizeof (double)) != 0;
+}
+static char buf[10000];
+static double zero = 0.0;
+int main ()
+{
+  int result = 0;
+  if (sprintf (buf, "%f", 1.0 / zero) < 0
+      || (strcmp (buf, "inf") != 0 && strcmp (buf, "infinity") != 0))
+    result |= 1;
+  if (sprintf (buf, "%f", -1.0 / zero) < 0
+      || (strcmp (buf, "-inf") != 0 && strcmp (buf, "-infinity") != 0))
+    result |= 1;
+  if (sprintf (buf, "%f", zero / zero) < 0
+      || !strisnan (buf, 0, strlen (buf)))
+    result |= 2;
+  if (sprintf (buf, "%e", 1.0 / zero) < 0
+      || (strcmp (buf, "inf") != 0 && strcmp (buf, "infinity") != 0))
+    result |= 4;
+  if (sprintf (buf, "%e", -1.0 / zero) < 0
+      || (strcmp (buf, "-inf") != 0 && strcmp (buf, "-infinity") != 0))
+    result |= 4;
+  if (sprintf (buf, "%e", zero / zero) < 0
+      || !strisnan (buf, 0, strlen (buf)))
+    result |= 8;
+  if (sprintf (buf, "%g", 1.0 / zero) < 0
+      || (strcmp (buf, "inf") != 0 && strcmp (buf, "infinity") != 0))
+    result |= 16;
+  if (sprintf (buf, "%g", -1.0 / zero) < 0
+      || (strcmp (buf, "-inf") != 0 && strcmp (buf, "-infinity") != 0))
+    result |= 16;
+  if (sprintf (buf, "%g", zero / zero) < 0
+      || !strisnan (buf, 0, strlen (buf)))
+    result |= 32;
+  /* This test fails on HP-UX 10.20.  */
+  if (have_minus_zero ())
+    if (sprintf (buf, "%g", - zero) < 0
+        || strcmp (buf, "-0") != 0)
+    result |= 64;
+  return result;
+}]])],
+        [gl_cv_func_printf_infinite=yes],
+        [gl_cv_func_printf_infinite=no],
+        [
+         case "$host_os" in
+changequote(,)dnl
+                                 # Guess yes on glibc systems.
+           *-gnu* | gnu*)        gl_cv_func_printf_infinite="guessing yes";;
+                                 # Guess yes on musl systems.
+           *-musl*)              gl_cv_func_printf_infinite="guessing yes";;
+                                 # Guess yes on FreeBSD >= 6.
+           freebsd[1-5].*)       gl_cv_func_printf_infinite="guessing no";;
+           freebsd* | kfreebsd*) gl_cv_func_printf_infinite="guessing yes";;
+                                 # Guess yes on Mac OS X >= 10.3.
+           darwin[1-6].*)        gl_cv_func_printf_infinite="guessing no";;
+           darwin*)              gl_cv_func_printf_infinite="guessing yes";;
+                                 # Guess yes on HP-UX >= 11.
+           hpux[7-9]* | hpux10*) gl_cv_func_printf_infinite="guessing no";;
+           hpux*)                gl_cv_func_printf_infinite="guessing yes";;
+                                 # Guess yes on NetBSD >= 3.
+           netbsd[1-2]* | netbsdelf[1-2]* | netbsdaout[1-2]* | netbsdcoff[1-2]*)
+                                 gl_cv_func_printf_infinite="guessing no";;
+           netbsd*)              gl_cv_func_printf_infinite="guessing yes";;
+                                 # Guess yes on OpenBSD >= 6.0.
+           openbsd[1-5].*)       gl_cv_func_printf_infinite="guessing no";;
+           openbsd*)             gl_cv_func_printf_infinite="guessing yes";;
+                                 # Guess yes on BeOS.
+           beos*)                gl_cv_func_printf_infinite="guessing yes";;
+                                 # Guess no on Android.
+           linux*-android*)      gl_cv_func_printf_infinite="guessing no";;
+changequote([,])dnl
+                                 # Guess yes on MSVC, no on mingw.
+           mingw*)               AC_EGREP_CPP([Known], [
+#ifdef _MSC_VER
+ Known
+#endif
+                                   ],
+                                   [gl_cv_func_printf_infinite="guessing yes"],
+                                   [gl_cv_func_printf_infinite="guessing no"])
+                                 ;;
+                                 # If we don't know, obey --enable-cross-guesses.
+           *)                    gl_cv_func_printf_infinite="$gl_cross_guess_normal";;
+         esac
+        ])
+    ])
+])
+
+dnl Test whether the *printf family of functions supports infinite and NaN
+dnl 'long double' arguments in the %f, %e, %g directives. (ISO C99, POSIX:2001)
+dnl Result is gl_cv_func_printf_infinite_long_double.
+
+AC_DEFUN([gl_PRINTF_INFINITE_LONG_DOUBLE],
+[
+  AC_REQUIRE([gl_PRINTF_LONG_DOUBLE])
+  AC_REQUIRE([AC_PROG_CC])
+  AC_REQUIRE([gl_BIGENDIAN])
+  AC_REQUIRE([gl_LONG_DOUBLE_VS_DOUBLE])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  dnl The user can set or unset the variable gl_printf_safe to indicate
+  dnl that he wishes a safe handling of non-IEEE-754 'long double' values.
+  if test -n "$gl_printf_safe"; then
+    AC_DEFINE([CHECK_PRINTF_SAFE], [1],
+      [Define if you wish *printf() functions that have a safe handling of
+       non-IEEE-754 'long double' values.])
+  fi
+  case "$gl_cv_func_printf_long_double" in
+    *yes)
+      AC_CACHE_CHECK([whether printf supports infinite 'long double' arguments],
+        [gl_cv_func_printf_infinite_long_double],
+        [
+          AC_RUN_IFELSE(
+            [AC_LANG_SOURCE([[
+]GL_NOCRASH[
+#include <float.h>
+#include <stdio.h>
+#include <string.h>
+static int
+strisnan (const char *string, size_t start_index, size_t end_index)
+{
+  if (start_index < end_index)
+    {
+      if (string[start_index] == '-')
+        start_index++;
+      if (start_index + 3 <= end_index
+          && memcmp (string + start_index, "nan", 3) == 0)
+        {
+          start_index += 3;
+          if (start_index == end_index
+              || (string[start_index] == '(' && string[end_index - 1] == ')'))
+            return 1;
+        }
+    }
+  return 0;
+}
+static char buf[10000];
+static long double zeroL = 0.0L;
+int main ()
+{
+  int result = 0;
+  nocrash_init();
+  if (sprintf (buf, "%Lf", 1.0L / zeroL) < 0
+      || (strcmp (buf, "inf") != 0 && strcmp (buf, "infinity") != 0))
+    result |= 1;
+  if (sprintf (buf, "%Lf", -1.0L / zeroL) < 0
+      || (strcmp (buf, "-inf") != 0 && strcmp (buf, "-infinity") != 0))
+    result |= 1;
+  if (sprintf (buf, "%Lf", zeroL / zeroL) < 0
+      || !strisnan (buf, 0, strlen (buf)))
+    result |= 1;
+  if (sprintf (buf, "%Le", 1.0L / zeroL) < 0
+      || (strcmp (buf, "inf") != 0 && strcmp (buf, "infinity") != 0))
+    result |= 1;
+  if (sprintf (buf, "%Le", -1.0L / zeroL) < 0
+      || (strcmp (buf, "-inf") != 0 && strcmp (buf, "-infinity") != 0))
+    result |= 1;
+  if (sprintf (buf, "%Le", zeroL / zeroL) < 0
+      || !strisnan (buf, 0, strlen (buf)))
+    result |= 1;
+  if (sprintf (buf, "%Lg", 1.0L / zeroL) < 0
+      || (strcmp (buf, "inf") != 0 && strcmp (buf, "infinity") != 0))
+    result |= 1;
+  if (sprintf (buf, "%Lg", -1.0L / zeroL) < 0
+      || (strcmp (buf, "-inf") != 0 && strcmp (buf, "-infinity") != 0))
+    result |= 1;
+  if (sprintf (buf, "%Lg", zeroL / zeroL) < 0
+      || !strisnan (buf, 0, strlen (buf)))
+    result |= 1;
+#if CHECK_PRINTF_SAFE && ((defined __ia64 && LDBL_MANT_DIG == 64) || (defined __x86_64__ || defined __amd64__) || (defined __i386 || defined __i386__ || defined _I386 || defined _M_IX86 || defined _X86_)) && !HAVE_SAME_LONG_DOUBLE_AS_DOUBLE
+/* Representation of an 80-bit 'long double' as an initializer for a sequence
+   of 'unsigned int' words.  */
+# ifdef WORDS_BIGENDIAN
+#  define LDBL80_WORDS(exponent,manthi,mantlo) \
+     { ((unsigned int) (exponent) << 16) | ((unsigned int) (manthi) >> 16), \
+       ((unsigned int) (manthi) << 16) | ((unsigned int) (mantlo) >> 16),   \
+       (unsigned int) (mantlo) << 16                                        \
+     }
+# else
+#  define LDBL80_WORDS(exponent,manthi,mantlo) \
+     { mantlo, manthi, exponent }
+# endif
+  { /* Quiet NaN.  */
+    static union { unsigned int word[4]; long double value; } x =
+      { LDBL80_WORDS (0xFFFF, 0xC3333333, 0x00000000) };
+    if (sprintf (buf, "%Lf", x.value) < 0
+        || !strisnan (buf, 0, strlen (buf)))
+      result |= 2;
+    if (sprintf (buf, "%Le", x.value) < 0
+        || !strisnan (buf, 0, strlen (buf)))
+      result |= 2;
+    if (sprintf (buf, "%Lg", x.value) < 0
+        || !strisnan (buf, 0, strlen (buf)))
+      result |= 2;
+  }
+  {
+    /* Signalling NaN.  */
+    static union { unsigned int word[4]; long double value; } x =
+      { LDBL80_WORDS (0xFFFF, 0x83333333, 0x00000000) };
+    if (sprintf (buf, "%Lf", x.value) < 0
+        || !strisnan (buf, 0, strlen (buf)))
+      result |= 2;
+    if (sprintf (buf, "%Le", x.value) < 0
+        || !strisnan (buf, 0, strlen (buf)))
+      result |= 2;
+    if (sprintf (buf, "%Lg", x.value) < 0
+        || !strisnan (buf, 0, strlen (buf)))
+      result |= 2;
+  }
+  { /* Pseudo-NaN.  */
+    static union { unsigned int word[4]; long double value; } x =
+      { LDBL80_WORDS (0xFFFF, 0x40000001, 0x00000000) };
+    if (sprintf (buf, "%Lf", x.value) <= 0)
+      result |= 4;
+    if (sprintf (buf, "%Le", x.value) <= 0)
+      result |= 4;
+    if (sprintf (buf, "%Lg", x.value) <= 0)
+      result |= 4;
+  }
+  { /* Pseudo-Infinity.  */
+    static union { unsigned int word[4]; long double value; } x =
+      { LDBL80_WORDS (0xFFFF, 0x00000000, 0x00000000) };
+    if (sprintf (buf, "%Lf", x.value) <= 0)
+      result |= 8;
+    if (sprintf (buf, "%Le", x.value) <= 0)
+      result |= 8;
+    if (sprintf (buf, "%Lg", x.value) <= 0)
+      result |= 8;
+  }
+  { /* Pseudo-Zero.  */
+    static union { unsigned int word[4]; long double value; } x =
+      { LDBL80_WORDS (0x4004, 0x00000000, 0x00000000) };
+    if (sprintf (buf, "%Lf", x.value) <= 0)
+      result |= 16;
+    if (sprintf (buf, "%Le", x.value) <= 0)
+      result |= 16;
+    if (sprintf (buf, "%Lg", x.value) <= 0)
+      result |= 16;
+  }
+  { /* Unnormalized number.  */
+    static union { unsigned int word[4]; long double value; } x =
+      { LDBL80_WORDS (0x4000, 0x63333333, 0x00000000) };
+    if (sprintf (buf, "%Lf", x.value) <= 0)
+      result |= 32;
+    if (sprintf (buf, "%Le", x.value) <= 0)
+      result |= 32;
+    if (sprintf (buf, "%Lg", x.value) <= 0)
+      result |= 32;
+  }
+  { /* Pseudo-Denormal.  */
+    static union { unsigned int word[4]; long double value; } x =
+      { LDBL80_WORDS (0x0000, 0x83333333, 0x00000000) };
+    if (sprintf (buf, "%Lf", x.value) <= 0)
+      result |= 64;
+    if (sprintf (buf, "%Le", x.value) <= 0)
+      result |= 64;
+    if (sprintf (buf, "%Lg", x.value) <= 0)
+      result |= 64;
+  }
+#endif
+  return result;
+}]])],
+            [gl_cv_func_printf_infinite_long_double=yes],
+            [gl_cv_func_printf_infinite_long_double=no],
+            [case "$host_cpu" in
+                                     # Guess no on ia64, x86_64, i386.
+               ia64 | x86_64 | i*86) gl_cv_func_printf_infinite_long_double="guessing no";;
+               *)
+                 case "$host_os" in
+changequote(,)dnl
+                                         # Guess yes on glibc systems.
+                   *-gnu* | gnu*)        gl_cv_func_printf_infinite_long_double="guessing yes";;
+                                         # Guess yes on musl systems.
+                   *-musl*)              gl_cv_func_printf_infinite_long_double="guessing yes";;
+                                         # Guess yes on FreeBSD >= 6.
+                   freebsd[1-5].*)       gl_cv_func_printf_infinite_long_double="guessing no";;
+                   freebsd* | kfreebsd*) gl_cv_func_printf_infinite_long_double="guessing yes";;
+                                         # Guess yes on HP-UX >= 11.
+                   hpux[7-9]* | hpux10*) gl_cv_func_printf_infinite_long_double="guessing no";;
+                   hpux*)                gl_cv_func_printf_infinite_long_double="guessing yes";;
+                                         # Guess yes on OpenBSD >= 6.0.
+                   openbsd[1-5].*)       gl_cv_func_printf_infinite_long_double="guessing no";;
+                   openbsd*)             gl_cv_func_printf_infinite_long_double="guessing yes";;
+                                         # Guess no on Android.
+                   linux*-android*)      gl_cv_func_printf_infinite_long_double="guessing no";;
+changequote([,])dnl
+                                         # Guess yes on MSVC, no on mingw.
+                   mingw*)               AC_EGREP_CPP([Known], [
+#ifdef _MSC_VER
+ Known
+#endif
+                                           ],
+                                           [gl_cv_func_printf_infinite_long_double="guessing yes"],
+                                           [gl_cv_func_printf_infinite_long_double="guessing no"])
+                                         ;;
+                                         # If we don't know, obey --enable-cross-guesses.
+                   *)                    gl_cv_func_printf_infinite_long_double="$gl_cross_guess_normal";;
+                 esac
+                 ;;
+             esac
+            ])
+        ])
+      ;;
+    *)
+      gl_cv_func_printf_infinite_long_double="irrelevant"
+      ;;
+  esac
+])
+
+dnl Test whether the *printf family of functions supports the 'a' and 'A'
+dnl conversion specifier for hexadecimal output of floating-point numbers.
+dnl (ISO C99, POSIX:2001)
+dnl Result is gl_cv_func_printf_directive_a.
+
+AC_DEFUN([gl_PRINTF_DIRECTIVE_A],
+[
+  AC_REQUIRE([AC_PROG_CC])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_CACHE_CHECK([whether printf supports the 'a' and 'A' directives],
+    [gl_cv_func_printf_directive_a],
+    [
+      AC_RUN_IFELSE(
+        [AC_LANG_SOURCE([[
+#include <stdio.h>
+#include <string.h>
+static char buf[100];
+static double zero = 0.0;
+int main ()
+{
+  int result = 0;
+  if (sprintf (buf, "%a %d", 3.1416015625, 33, 44, 55) < 0
+      || (strcmp (buf, "0x1.922p+1 33") != 0
+          && strcmp (buf, "0x3.244p+0 33") != 0
+          && strcmp (buf, "0x6.488p-1 33") != 0
+          && strcmp (buf, "0xc.91p-2 33") != 0))
+    result |= 1;
+  if (sprintf (buf, "%A %d", -3.1416015625, 33, 44, 55) < 0
+      || (strcmp (buf, "-0X1.922P+1 33") != 0
+          && strcmp (buf, "-0X3.244P+0 33") != 0
+          && strcmp (buf, "-0X6.488P-1 33") != 0
+          && strcmp (buf, "-0XC.91P-2 33") != 0))
+    result |= 2;
+  /* This catches a FreeBSD 6.1 bug: it doesn't round.  */
+  if (sprintf (buf, "%.2a %d", 1.51, 33, 44, 55) < 0
+      || (strcmp (buf, "0x1.83p+0 33") != 0
+          && strcmp (buf, "0x3.05p-1 33") != 0
+          && strcmp (buf, "0x6.0ap-2 33") != 0
+          && strcmp (buf, "0xc.14p-3 33") != 0))
+    result |= 4;
+  /* This catches a Mac OS X 10.12.4 (Darwin 16.5) bug: it doesn't round.  */
+  if (sprintf (buf, "%.0a %d", 1.51, 33, 44, 55) < 0
+      || (strcmp (buf, "0x2p+0 33") != 0
+          && strcmp (buf, "0x3p-1 33") != 0
+          && strcmp (buf, "0x6p-2 33") != 0
+          && strcmp (buf, "0xcp-3 33") != 0))
+    result |= 4;
+  /* This catches a FreeBSD 6.1 bug.  See
+     <https://lists.gnu.org/r/bug-gnulib/2007-04/msg00107.html> */
+  if (sprintf (buf, "%010a %d", 1.0 / zero, 33, 44, 55) < 0
+      || buf[0] == '0')
+    result |= 8;
+  /* This catches a Mac OS X 10.3.9 (Darwin 7.9) bug.  */
+  if (sprintf (buf, "%.1a", 1.999) < 0
+      || (strcmp (buf, "0x1.0p+1") != 0
+          && strcmp (buf, "0x2.0p+0") != 0
+          && strcmp (buf, "0x4.0p-1") != 0
+          && strcmp (buf, "0x8.0p-2") != 0))
+    result |= 16;
+  /* This catches the same Mac OS X 10.3.9 (Darwin 7.9) bug and also a
+     glibc 2.4 bug <https://sourceware.org/bugzilla/show_bug.cgi?id=2908>.  */
+  if (sprintf (buf, "%.1La", 1.999L) < 0
+      || (strcmp (buf, "0x1.0p+1") != 0
+          && strcmp (buf, "0x2.0p+0") != 0
+          && strcmp (buf, "0x4.0p-1") != 0
+          && strcmp (buf, "0x8.0p-2") != 0))
+    result |= 32;
+  return result;
+}]])],
+        [gl_cv_func_printf_directive_a=yes],
+        [gl_cv_func_printf_directive_a=no],
+        [
+         case "$host_os" in
+                                 # Guess yes on glibc >= 2.5 systems.
+           *-gnu* | gnu*)
+             AC_EGREP_CPP([BZ2908], [
+               #include <features.h>
+               #ifdef __GNU_LIBRARY__
+                #if ((__GLIBC__ == 2 && __GLIBC_MINOR__ >= 5) || (__GLIBC__ > 2)) && !defined __UCLIBC__
+                 BZ2908
+                #endif
+               #endif
+               ],
+               [gl_cv_func_printf_directive_a="guessing yes"],
+               [gl_cv_func_printf_directive_a="guessing no"])
+             ;;
+                                 # Guess yes on musl systems.
+           *-musl*)              gl_cv_func_printf_directive_a="guessing yes";;
+                                 # Guess no on Android.
+           linux*-android*)      gl_cv_func_printf_directive_a="guessing no";;
+                                 # Guess no on native Windows.
+           mingw*)               gl_cv_func_printf_directive_a="guessing no";;
+                                 # If we don't know, obey --enable-cross-guesses.
+           *)                    gl_cv_func_printf_directive_a="$gl_cross_guess_normal";;
+         esac
+        ])
+    ])
+])
+
+dnl Test whether the *printf family of functions supports the %F format
+dnl directive. (ISO C99, POSIX:2001)
+dnl Result is gl_cv_func_printf_directive_f.
+
+AC_DEFUN([gl_PRINTF_DIRECTIVE_F],
+[
+  AC_REQUIRE([AC_PROG_CC])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_CACHE_CHECK([whether printf supports the 'F' directive],
+    [gl_cv_func_printf_directive_f],
+    [
+      AC_RUN_IFELSE(
+        [AC_LANG_SOURCE([[
+#include <stdio.h>
+#include <string.h>
+static char buf[100];
+static double zero = 0.0;
+int main ()
+{
+  int result = 0;
+  if (sprintf (buf, "%F %d", 1234567.0, 33, 44, 55) < 0
+      || strcmp (buf, "1234567.000000 33") != 0)
+    result |= 1;
+  if (sprintf (buf, "%F", 1.0 / zero) < 0
+      || (strcmp (buf, "INF") != 0 && strcmp (buf, "INFINITY") != 0))
+    result |= 2;
+  /* This catches a Cygwin 1.5.x bug.  */
+  if (sprintf (buf, "%.F", 1234.0) < 0
+      || strcmp (buf, "1234") != 0)
+    result |= 4;
+  return result;
+}]])],
+        [gl_cv_func_printf_directive_f=yes],
+        [gl_cv_func_printf_directive_f=no],
+        [
+         case "$host_os" in
+changequote(,)dnl
+                                 # Guess yes on glibc systems.
+           *-gnu* | gnu*)        gl_cv_func_printf_directive_f="guessing yes";;
+                                 # Guess yes on musl systems.
+           *-musl*)              gl_cv_func_printf_directive_f="guessing yes";;
+                                 # Guess yes on FreeBSD >= 6.
+           freebsd[1-5].*)       gl_cv_func_printf_directive_f="guessing no";;
+           freebsd* | kfreebsd*) gl_cv_func_printf_directive_f="guessing yes";;
+                                 # Guess yes on Mac OS X >= 10.3.
+           darwin[1-6].*)        gl_cv_func_printf_directive_f="guessing no";;
+           darwin*)              gl_cv_func_printf_directive_f="guessing yes";;
+                                 # Guess yes on OpenBSD >= 6.0.
+           openbsd[1-5].*)       gl_cv_func_printf_directive_f="guessing no";;
+           openbsd*)             gl_cv_func_printf_directive_f="guessing yes";;
+                                 # Guess yes on Solaris >= 2.10.
+           solaris2.[1-9][0-9]*) gl_cv_func_printf_directive_f="guessing yes";;
+           solaris*)             gl_cv_func_printf_directive_f="guessing no";;
+                                 # Guess no on Android.
+           linux*-android*)      gl_cv_func_printf_directive_f="guessing no";;
+changequote([,])dnl
+                                 # Guess yes on MSVC, no on mingw.
+           mingw*)               AC_EGREP_CPP([Known], [
+#ifdef _MSC_VER
+ Known
+#endif
+                                   ],
+                                   [gl_cv_func_printf_directive_f="guessing yes"],
+                                   [gl_cv_func_printf_directive_f="guessing no"])
+                                 ;;
+                                 # If we don't know, obey --enable-cross-guesses.
+           *)                    gl_cv_func_printf_directive_f="$gl_cross_guess_normal";;
+         esac
+        ])
+    ])
+])
+
+dnl Test whether the *printf family of functions supports the %n format
+dnl directive. (ISO C99, POSIX:2001)
+dnl Result is gl_cv_func_printf_directive_n.
+
+AC_DEFUN([gl_PRINTF_DIRECTIVE_N],
+[
+  AC_REQUIRE([AC_PROG_CC])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_CACHE_CHECK([whether printf supports the 'n' directive],
+    [gl_cv_func_printf_directive_n],
+    [
+      AC_RUN_IFELSE(
+        [AC_LANG_SOURCE([[
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#ifdef _MSC_VER
+#include <inttypes.h>
+/* See page about "Parameter Validation" on msdn.microsoft.com.
+   <https://docs.microsoft.com/en-us/cpp/c-runtime-library/parameter-validation>
+   <https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/set-invalid-parameter-handler-set-thread-local-invalid-parameter-handler>  */
+static void cdecl
+invalid_parameter_handler (const wchar_t *expression,
+                           const wchar_t *function,
+                           const wchar_t *file, unsigned int line,
+                           uintptr_t dummy)
+{
+  exit (1);
+}
+#endif
+static char fmtstring[10];
+static char buf[100];
+int main ()
+{
+  int count = -1;
+#ifdef _MSC_VER
+  _set_invalid_parameter_handler (invalid_parameter_handler);
+#endif
+  /* Copy the format string.  Some systems (glibc with _FORTIFY_SOURCE=2)
+     support %n in format strings in read-only memory but not in writable
+     memory.  */
+  strcpy (fmtstring, "%d %n");
+  if (sprintf (buf, fmtstring, 123, &count, 33, 44, 55) < 0
+      || strcmp (buf, "123 ") != 0
+      || count != 4)
+    return 1;
+  return 0;
+}]])],
+        [gl_cv_func_printf_directive_n=yes],
+        [gl_cv_func_printf_directive_n=no],
+        [case "$host_os" in
+                            # Guess no on glibc when _FORTIFY_SOURCE >= 2.
+           *-gnu* | gnu*)   AC_COMPILE_IFELSE(
+                              [AC_LANG_SOURCE(
+                                 [[#if _FORTIFY_SOURCE >= 2
+                                    error fail
+                                   #endif
+                                 ]])],
+                              [gl_cv_func_printf_directive_n="guessing yes"],
+                              [gl_cv_func_printf_directive_n="guessing no"])
+                            ;;
+                            # Guess no on Android.
+           linux*-android*) gl_cv_func_printf_directive_n="guessing no";;
+                            # Guess no on native Windows.
+           mingw*)          gl_cv_func_printf_directive_n="guessing no";;
+           *)               gl_cv_func_printf_directive_n="guessing yes";;
+         esac
+        ])
+    ])
+])
+
+dnl Test whether the *printf family of functions supports the %ls format
+dnl directive and in particular, when a precision is specified, whether
+dnl the functions stop converting the wide string argument when the number
+dnl of bytes that have been produced by this conversion equals or exceeds
+dnl the precision.
+dnl Result is gl_cv_func_printf_directive_ls.
+
+AC_DEFUN([gl_PRINTF_DIRECTIVE_LS],
+[
+  AC_REQUIRE([AC_PROG_CC])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_CACHE_CHECK([whether printf supports the 'ls' directive],
+    [gl_cv_func_printf_directive_ls],
+    [
+      AC_RUN_IFELSE(
+        [AC_LANG_SOURCE([[
+#include <stdio.h>
+#include <wchar.h>
+#include <string.h>
+int main ()
+{
+  int result = 0;
+  char buf[100];
+  /* Test whether %ls works at all.
+     This test fails on OpenBSD 4.0, IRIX 6.5, Solaris 2.6, Haiku, but not on
+     Cygwin 1.5.  */
+  {
+    static const wchar_t wstring[] = { 'a', 'b', 'c', 0 };
+    buf[0] = '\0';
+    if (sprintf (buf, "%ls", wstring) < 0
+        || strcmp (buf, "abc") != 0)
+      result |= 1;
+  }
+  /* This test fails on IRIX 6.5, Solaris 2.6, Cygwin 1.5, Haiku (with an
+     assertion failure inside libc), but not on OpenBSD 4.0.  */
+  {
+    static const wchar_t wstring[] = { 'a', 0 };
+    buf[0] = '\0';
+    if (sprintf (buf, "%ls", wstring) < 0
+        || strcmp (buf, "a") != 0)
+      result |= 2;
+  }
+  /* Test whether precisions in %ls are supported as specified in ISO C 99
+     section 7.19.6.1:
+       "If a precision is specified, no more than that many bytes are written
+        (including shift sequences, if any), and the array shall contain a
+        null wide character if, to equal the multibyte character sequence
+        length given by the precision, the function would need to access a
+        wide character one past the end of the array."
+     This test fails on Solaris 10.  */
+  {
+    static const wchar_t wstring[] = { 'a', 'b', (wchar_t) 0xfdfdfdfd, 0 };
+    buf[0] = '\0';
+    if (sprintf (buf, "%.2ls", wstring) < 0
+        || strcmp (buf, "ab") != 0)
+      result |= 8;
+  }
+  return result;
+}]])],
+        [gl_cv_func_printf_directive_ls=yes],
+        [gl_cv_func_printf_directive_ls=no],
+        [
+changequote(,)dnl
+         case "$host_os" in
+                            # Guess yes on OpenBSD >= 6.0.
+           openbsd[1-5].*)  gl_cv_func_printf_directive_ls="guessing no";;
+           openbsd*)        gl_cv_func_printf_directive_ls="guessing yes";;
+           irix*)           gl_cv_func_printf_directive_ls="guessing no";;
+           solaris*)        gl_cv_func_printf_directive_ls="guessing no";;
+           cygwin*)         gl_cv_func_printf_directive_ls="guessing no";;
+           beos* | haiku*)  gl_cv_func_printf_directive_ls="guessing no";;
+                            # Guess no on Android.
+           linux*-android*) gl_cv_func_printf_directive_ls="guessing no";;
+                            # Guess yes on native Windows.
+           mingw*)          gl_cv_func_printf_directive_ls="guessing yes";;
+           *)               gl_cv_func_printf_directive_ls="guessing yes";;
+         esac
+changequote([,])dnl
+        ])
+    ])
+])
+
+dnl Test whether the *printf family of functions supports POSIX/XSI format
+dnl strings with positions. (POSIX:2001)
+dnl Result is gl_cv_func_printf_positions.
+
+AC_DEFUN([gl_PRINTF_POSITIONS],
+[
+  AC_REQUIRE([AC_PROG_CC])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_CACHE_CHECK([whether printf supports POSIX/XSI format strings with positions],
+    [gl_cv_func_printf_positions],
+    [
+      AC_RUN_IFELSE(
+        [AC_LANG_SOURCE([[
+#include <stdio.h>
+#include <string.h>
+/* The string "%2$d %1$d", with dollar characters protected from the shell's
+   dollar expansion (possibly an autoconf bug).  */
+static char format[] = { '%', '2', '$', 'd', ' ', '%', '1', '$', 'd', '\0' };
+static char buf[100];
+int main ()
+{
+  sprintf (buf, format, 33, 55);
+  return (strcmp (buf, "55 33") != 0);
+}]])],
+        [gl_cv_func_printf_positions=yes],
+        [gl_cv_func_printf_positions=no],
+        [
+changequote(,)dnl
+         case "$host_os" in
+           netbsd[1-3]* | netbsdelf[1-3]* | netbsdaout[1-3]* | netbsdcoff[1-3]*)
+                            gl_cv_func_printf_positions="guessing no";;
+           beos*)           gl_cv_func_printf_positions="guessing no";;
+                            # Guess yes on Android.
+           linux*-android*) gl_cv_func_printf_positions="guessing yes";;
+                            # Guess no on native Windows.
+           mingw* | pw*)    gl_cv_func_printf_positions="guessing no";;
+           *)               gl_cv_func_printf_positions="guessing yes";;
+         esac
+changequote([,])dnl
+        ])
+    ])
+])
+
+dnl Test whether the *printf family of functions supports POSIX/XSI format
+dnl strings with the ' flag for grouping of decimal digits. (POSIX:2001)
+dnl Result is gl_cv_func_printf_flag_grouping.
+
+AC_DEFUN([gl_PRINTF_FLAG_GROUPING],
+[
+  AC_REQUIRE([AC_PROG_CC])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_CACHE_CHECK([whether printf supports the grouping flag],
+    [gl_cv_func_printf_flag_grouping],
+    [
+      AC_RUN_IFELSE(
+        [AC_LANG_SOURCE([[
+#include <stdio.h>
+#include <string.h>
+static char buf[100];
+int main ()
+{
+  if (sprintf (buf, "%'d %d", 1234567, 99) < 0
+      || buf[strlen (buf) - 1] != '9')
+    return 1;
+  return 0;
+}]])],
+        [gl_cv_func_printf_flag_grouping=yes],
+        [gl_cv_func_printf_flag_grouping=no],
+        [
+changequote(,)dnl
+         case "$host_os" in
+           cygwin*)         gl_cv_func_printf_flag_grouping="guessing no";;
+           netbsd*)         gl_cv_func_printf_flag_grouping="guessing no";;
+                            # Guess no on Android.
+           linux*-android*) gl_cv_func_printf_flag_grouping="guessing no";;
+                            # Guess no on native Windows.
+           mingw* | pw*)    gl_cv_func_printf_flag_grouping="guessing no";;
+           *)               gl_cv_func_printf_flag_grouping="guessing yes";;
+         esac
+changequote([,])dnl
+        ])
+    ])
+])
+
+dnl Test whether the *printf family of functions supports the - flag correctly.
+dnl (ISO C99.) See
+dnl <https://lists.gnu.org/r/bug-coreutils/2008-02/msg00035.html>
+dnl Result is gl_cv_func_printf_flag_leftadjust.
+
+AC_DEFUN([gl_PRINTF_FLAG_LEFTADJUST],
+[
+  AC_REQUIRE([AC_PROG_CC])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_CACHE_CHECK([whether printf supports the left-adjust flag correctly],
+    [gl_cv_func_printf_flag_leftadjust],
+    [
+      AC_RUN_IFELSE(
+        [AC_LANG_SOURCE([[
+#include <stdio.h>
+#include <string.h>
+static char buf[100];
+int main ()
+{
+  /* Check that a '-' flag is not annihilated by a negative width.  */
+  if (sprintf (buf, "a%-*sc", -3, "b") < 0
+      || strcmp (buf, "ab  c") != 0)
+    return 1;
+  return 0;
+}]])],
+        [gl_cv_func_printf_flag_leftadjust=yes],
+        [gl_cv_func_printf_flag_leftadjust=no],
+        [
+changequote(,)dnl
+         case "$host_os" in
+                            # Guess yes on HP-UX 11.
+           hpux11*)         gl_cv_func_printf_flag_leftadjust="guessing yes";;
+                            # Guess no on HP-UX 10 and older.
+           hpux*)           gl_cv_func_printf_flag_leftadjust="guessing no";;
+                            # Guess yes on Android.
+           linux*-android*) gl_cv_func_printf_flag_leftadjust="guessing yes";;
+                            # Guess yes on native Windows.
+           mingw*)          gl_cv_func_printf_flag_leftadjust="guessing yes";;
+                            # Guess yes otherwise.
+           *)               gl_cv_func_printf_flag_leftadjust="guessing yes";;
+         esac
+changequote([,])dnl
+        ])
+    ])
+])
+
+dnl Test whether the *printf family of functions supports padding of non-finite
+dnl values with the 0 flag correctly. (ISO C99 + TC1 + TC2.) See
+dnl <https://lists.gnu.org/r/bug-gnulib/2007-04/msg00107.html>
+dnl Result is gl_cv_func_printf_flag_zero.
+
+AC_DEFUN([gl_PRINTF_FLAG_ZERO],
+[
+  AC_REQUIRE([AC_PROG_CC])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_CACHE_CHECK([whether printf supports the zero flag correctly],
+    [gl_cv_func_printf_flag_zero],
+    [
+      AC_RUN_IFELSE(
+        [AC_LANG_SOURCE([[
+#include <stdio.h>
+#include <string.h>
+static char buf[100];
+static double zero = 0.0;
+int main ()
+{
+  if (sprintf (buf, "%010f", 1.0 / zero, 33, 44, 55) < 0
+      || (strcmp (buf, "       inf") != 0
+          && strcmp (buf, "  infinity") != 0))
+    return 1;
+  return 0;
+}]])],
+        [gl_cv_func_printf_flag_zero=yes],
+        [gl_cv_func_printf_flag_zero=no],
+        [
+changequote(,)dnl
+         case "$host_os" in
+                            # Guess yes on glibc systems.
+           *-gnu* | gnu*)   gl_cv_func_printf_flag_zero="guessing yes";;
+                            # Guess yes on musl systems.
+           *-musl*)         gl_cv_func_printf_flag_zero="guessing yes";;
+                            # Guess yes on BeOS.
+           beos*)           gl_cv_func_printf_flag_zero="guessing yes";;
+                            # Guess no on Android.
+           linux*-android*) gl_cv_func_printf_flag_zero="guessing no";;
+                            # Guess no on native Windows.
+           mingw*)          gl_cv_func_printf_flag_zero="guessing no";;
+                            # If we don't know, obey --enable-cross-guesses.
+           *)               gl_cv_func_printf_flag_zero="$gl_cross_guess_normal";;
+         esac
+changequote([,])dnl
+        ])
+    ])
+])
+
+dnl Test whether the *printf family of functions supports large precisions.
+dnl On mingw, precisions larger than 512 are treated like 512, in integer,
+dnl floating-point or pointer output. On Solaris 10/x86, precisions larger
+dnl than 510 in floating-point output crash the program. On Solaris 10/SPARC,
+dnl precisions larger than 510 in floating-point output yield wrong results.
+dnl On AIX 7.1, precisions larger than 998 in floating-point output yield
+dnl wrong results. On BeOS, precisions larger than 1044 crash the program.
+dnl Result is gl_cv_func_printf_precision.
+
+AC_DEFUN([gl_PRINTF_PRECISION],
+[
+  AC_REQUIRE([AC_PROG_CC])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_CACHE_CHECK([whether printf supports large precisions],
+    [gl_cv_func_printf_precision],
+    [
+      AC_RUN_IFELSE(
+        [AC_LANG_SOURCE([[
+#include <stdio.h>
+#include <string.h>
+static char buf[5000];
+int main ()
+{
+  int result = 0;
+#ifdef __BEOS__
+  /* On BeOS, this would crash and show a dialog box.  Avoid the crash.  */
+  return 1;
+#endif
+  if (sprintf (buf, "%.4000d %d", 1, 33, 44) < 4000 + 3)
+    result |= 1;
+  if (sprintf (buf, "%.4000f %d", 1.0, 33, 44) < 4000 + 5)
+    result |= 2;
+  if (sprintf (buf, "%.511f %d", 1.0, 33, 44) < 511 + 5
+      || buf[0] != '1')
+    result |= 4;
+  if (sprintf (buf, "%.999f %d", 1.0, 33, 44) < 999 + 5
+      || buf[0] != '1')
+    result |= 4;
+  return result;
+}]])],
+        [gl_cv_func_printf_precision=yes],
+        [gl_cv_func_printf_precision=no],
+        [
+changequote(,)dnl
+         case "$host_os" in
+           # Guess no only on Solaris, native Windows, and BeOS systems.
+           solaris*)        gl_cv_func_printf_precision="guessing no" ;;
+           mingw* | pw*)    gl_cv_func_printf_precision="guessing no" ;;
+           beos*)           gl_cv_func_printf_precision="guessing no" ;;
+                            # Guess yes on Android.
+           linux*-android*) gl_cv_func_printf_precision="guessing yes" ;;
+           *)               gl_cv_func_printf_precision="guessing yes" ;;
+         esac
+changequote([,])dnl
+        ])
+    ])
+])
+
+dnl Test whether the *printf family of functions recovers gracefully in case
+dnl of an out-of-memory condition, or whether it crashes the entire program.
+dnl Result is gl_cv_func_printf_enomem.
+
+AC_DEFUN([gl_PRINTF_ENOMEM],
+[
+  AC_REQUIRE([AC_PROG_CC])
+  AC_REQUIRE([gl_MULTIARCH])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_CACHE_CHECK([whether printf survives out-of-memory conditions],
+    [gl_cv_func_printf_enomem],
+    [
+      gl_cv_func_printf_enomem="guessing no"
+      if test "$cross_compiling" = no; then
+        if test $APPLE_UNIVERSAL_BUILD = 0; then
+          AC_LANG_CONFTEST([AC_LANG_SOURCE([[
+]GL_NOCRASH[
+#include <stdio.h>
+#include <sys/types.h>
+#include <sys/time.h>
+#include <sys/resource.h>
+#include <errno.h>
+int main()
+{
+  struct rlimit limit;
+  int ret;
+  nocrash_init ();
+  /* Some printf implementations allocate temporary space with malloc.  */
+  /* On BSD systems, malloc() is limited by RLIMIT_DATA.  */
+#ifdef RLIMIT_DATA
+  if (getrlimit (RLIMIT_DATA, &limit) < 0)
+    return 77;
+  if (limit.rlim_max == RLIM_INFINITY || limit.rlim_max > 5000000)
+    limit.rlim_max = 5000000;
+  limit.rlim_cur = limit.rlim_max;
+  if (setrlimit (RLIMIT_DATA, &limit) < 0)
+    return 77;
+#endif
+  /* On Linux systems, malloc() is limited by RLIMIT_AS.  */
+#ifdef RLIMIT_AS
+  if (getrlimit (RLIMIT_AS, &limit) < 0)
+    return 77;
+  if (limit.rlim_max == RLIM_INFINITY || limit.rlim_max > 5000000)
+    limit.rlim_max = 5000000;
+  limit.rlim_cur = limit.rlim_max;
+  if (setrlimit (RLIMIT_AS, &limit) < 0)
+    return 77;
+#endif
+  /* Some printf implementations allocate temporary space on the stack.  */
+#ifdef RLIMIT_STACK
+  if (getrlimit (RLIMIT_STACK, &limit) < 0)
+    return 77;
+  if (limit.rlim_max == RLIM_INFINITY || limit.rlim_max > 5000000)
+    limit.rlim_max = 5000000;
+  limit.rlim_cur = limit.rlim_max;
+  if (setrlimit (RLIMIT_STACK, &limit) < 0)
+    return 77;
+#endif
+  ret = printf ("%.5000000f", 1.0);
+  return !(ret == 5000002 || (ret < 0 && errno == ENOMEM));
+}
+          ]])])
+          if AC_TRY_EVAL([ac_link]) && test -s conftest$ac_exeext; then
+            (./conftest 2>&AS_MESSAGE_LOG_FD
+             result=$?
+             _AS_ECHO_LOG([\$? = $result])
+             if test $result != 0 && test $result != 77; then result=1; fi
+             exit $result
+            ) >/dev/null 2>/dev/null
+            case $? in
+              0) gl_cv_func_printf_enomem="yes" ;;
+              77) gl_cv_func_printf_enomem="guessing no" ;;
+              *) gl_cv_func_printf_enomem="no" ;;
+            esac
+          else
+            gl_cv_func_printf_enomem="guessing no"
+          fi
+          rm -fr conftest*
+        else
+          dnl A universal build on Apple Mac OS X platforms.
+          dnl The result would be 'no' in 32-bit mode and 'yes' in 64-bit mode.
+          dnl But we need a configuration result that is valid in both modes.
+          gl_cv_func_printf_enomem="guessing no"
+        fi
+      fi
+      if test "$gl_cv_func_printf_enomem" = "guessing no"; then
+changequote(,)dnl
+        case "$host_os" in
+                           # Guess yes on glibc systems.
+          *-gnu* | gnu*)   gl_cv_func_printf_enomem="guessing yes";;
+                           # Guess yes on Solaris.
+          solaris*)        gl_cv_func_printf_enomem="guessing yes";;
+                           # Guess yes on AIX.
+          aix*)            gl_cv_func_printf_enomem="guessing yes";;
+                           # Guess yes on HP-UX/hppa.
+          hpux*)           case "$host_cpu" in
+                             hppa*) gl_cv_func_printf_enomem="guessing yes";;
+                             *)     gl_cv_func_printf_enomem="guessing no";;
+                           esac
+                           ;;
+                           # Guess yes on IRIX.
+          irix*)           gl_cv_func_printf_enomem="guessing yes";;
+                           # Guess yes on OSF/1.
+          osf*)            gl_cv_func_printf_enomem="guessing yes";;
+                           # Guess yes on BeOS.
+          beos*)           gl_cv_func_printf_enomem="guessing yes";;
+                           # Guess yes on Haiku.
+          haiku*)          gl_cv_func_printf_enomem="guessing yes";;
+                           # Guess no on Android.
+          linux*-android*) gl_cv_func_printf_enomem="guessing no";;
+                           # If we don't know, obey --enable-cross-guesses.
+          *)               gl_cv_func_printf_enomem="$gl_cross_guess_normal";;
+        esac
+changequote([,])dnl
+      fi
+    ])
+])
+
+dnl Test whether the snprintf function exists. (ISO C99, POSIX:2001)
+dnl Result is ac_cv_func_snprintf.
+
+AC_DEFUN([gl_SNPRINTF_PRESENCE],
+[
+  AC_CHECK_FUNCS_ONCE([snprintf])
+])
+
+dnl Test whether the string produced by the snprintf function is always NUL
+dnl terminated. (ISO C99, POSIX:2001)
+dnl Result is gl_cv_func_snprintf_truncation_c99.
+
+AC_DEFUN_ONCE([gl_SNPRINTF_TRUNCATION_C99],
+[
+  AC_REQUIRE([AC_PROG_CC])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_REQUIRE([gl_SNPRINTF_PRESENCE])
+  AC_CACHE_CHECK([whether snprintf truncates the result as in C99],
+    [gl_cv_func_snprintf_truncation_c99],
+    [
+      AC_RUN_IFELSE(
+        [AC_LANG_SOURCE([[
+#include <stdio.h>
+#include <string.h>
+#if HAVE_SNPRINTF
+# define my_snprintf snprintf
+#else
+# include <stdarg.h>
+static int my_snprintf (char *buf, int size, const char *format, ...)
+{
+  va_list args;
+  int ret;
+  va_start (args, format);
+  ret = vsnprintf (buf, size, format, args);
+  va_end (args);
+  return ret;
+}
+#endif
+static char buf[100];
+int main ()
+{
+  strcpy (buf, "ABCDEF");
+  my_snprintf (buf, 3, "%d %d", 4567, 89);
+  if (memcmp (buf, "45\0DEF", 6) != 0)
+    return 1;
+  return 0;
+}]])],
+        [gl_cv_func_snprintf_truncation_c99=yes],
+        [gl_cv_func_snprintf_truncation_c99=no],
+        [
+changequote(,)dnl
+         case "$host_os" in
+                                 # Guess yes on glibc systems.
+           *-gnu* | gnu*)        gl_cv_func_snprintf_truncation_c99="guessing yes";;
+                                 # Guess yes on musl systems.
+           *-musl*)              gl_cv_func_snprintf_truncation_c99="guessing yes";;
+                                 # Guess yes on FreeBSD >= 5.
+           freebsd[1-4].*)       gl_cv_func_snprintf_truncation_c99="guessing no";;
+           freebsd* | kfreebsd*) gl_cv_func_snprintf_truncation_c99="guessing yes";;
+                                 # Guess yes on Mac OS X >= 10.3.
+           darwin[1-6].*)        gl_cv_func_snprintf_truncation_c99="guessing no";;
+           darwin*)              gl_cv_func_snprintf_truncation_c99="guessing yes";;
+                                 # Guess yes on OpenBSD >= 3.9.
+           openbsd[1-2].* | openbsd3.[0-8] | openbsd3.[0-8].*)
+                                 gl_cv_func_snprintf_truncation_c99="guessing no";;
+           openbsd*)             gl_cv_func_snprintf_truncation_c99="guessing yes";;
+                                 # Guess yes on Solaris >= 2.6.
+           solaris2.[0-5] | solaris2.[0-5].*)
+                                 gl_cv_func_snprintf_truncation_c99="guessing no";;
+           solaris*)             gl_cv_func_snprintf_truncation_c99="guessing yes";;
+                                 # Guess yes on AIX >= 4.
+           aix[1-3]*)            gl_cv_func_snprintf_truncation_c99="guessing no";;
+           aix*)                 gl_cv_func_snprintf_truncation_c99="guessing yes";;
+                                 # Guess yes on HP-UX >= 11.
+           hpux[7-9]* | hpux10*) gl_cv_func_snprintf_truncation_c99="guessing no";;
+           hpux*)                gl_cv_func_snprintf_truncation_c99="guessing yes";;
+                                 # Guess yes on IRIX >= 6.5.
+           irix6.5)              gl_cv_func_snprintf_truncation_c99="guessing yes";;
+                                 # Guess yes on OSF/1 >= 5.
+           osf[3-4]*)            gl_cv_func_snprintf_truncation_c99="guessing no";;
+           osf*)                 gl_cv_func_snprintf_truncation_c99="guessing yes";;
+                                 # Guess yes on NetBSD >= 3.
+           netbsd[1-2]* | netbsdelf[1-2]* | netbsdaout[1-2]* | netbsdcoff[1-2]*)
+                                 gl_cv_func_snprintf_truncation_c99="guessing no";;
+           netbsd*)              gl_cv_func_snprintf_truncation_c99="guessing yes";;
+                                 # Guess yes on BeOS.
+           beos*)                gl_cv_func_snprintf_truncation_c99="guessing yes";;
+                                 # Guess yes on Android.
+           linux*-android*)      gl_cv_func_snprintf_truncation_c99="guessing yes";;
+                                 # Guess no on native Windows.
+           mingw*)               gl_cv_func_snprintf_truncation_c99="guessing no";;
+                                 # If we don't know, obey --enable-cross-guesses.
+           *)                    gl_cv_func_snprintf_truncation_c99="$gl_cross_guess_normal";;
+         esac
+changequote([,])dnl
+        ])
+    ])
+])
+
+dnl Test whether the return value of the snprintf function is the number
+dnl of bytes (excluding the terminating NUL) that would have been produced
+dnl if the buffer had been large enough. (ISO C99, POSIX:2001)
+dnl For example, this test program fails on IRIX 6.5:
+dnl     ---------------------------------------------------------------------
+dnl     #include <stdio.h>
+dnl     int main()
+dnl     {
+dnl       static char buf[8];
+dnl       int retval = snprintf (buf, 3, "%d", 12345);
+dnl       return retval >= 0 && retval < 3;
+dnl     }
+dnl     ---------------------------------------------------------------------
+dnl Result is gl_cv_func_snprintf_retval_c99.
+
+AC_DEFUN_ONCE([gl_SNPRINTF_RETVAL_C99],
+[
+  AC_REQUIRE([AC_PROG_CC])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_REQUIRE([gl_SNPRINTF_PRESENCE])
+  AC_CACHE_CHECK([whether snprintf returns a byte count as in C99],
+    [gl_cv_func_snprintf_retval_c99],
+    [
+      AC_RUN_IFELSE(
+        [AC_LANG_SOURCE([[
+#include <stdio.h>
+#include <string.h>
+#if HAVE_SNPRINTF
+# define my_snprintf snprintf
+#else
+# include <stdarg.h>
+static int my_snprintf (char *buf, int size, const char *format, ...)
+{
+  va_list args;
+  int ret;
+  va_start (args, format);
+  ret = vsnprintf (buf, size, format, args);
+  va_end (args);
+  return ret;
+}
+#endif
+static char buf[100];
+int main ()
+{
+  strcpy (buf, "ABCDEF");
+  if (my_snprintf (buf, 3, "%d %d", 4567, 89) != 7)
+    return 1;
+  if (my_snprintf (buf, 0, "%d %d", 4567, 89) != 7)
+    return 2;
+  if (my_snprintf (NULL, 0, "%d %d", 4567, 89) != 7)
+    return 3;
+  return 0;
+}]])],
+        [gl_cv_func_snprintf_retval_c99=yes],
+        [gl_cv_func_snprintf_retval_c99=no],
+        [case "$host_os" in
+changequote(,)dnl
+                                 # Guess yes on glibc systems.
+           *-gnu* | gnu*)        gl_cv_func_snprintf_retval_c99="guessing yes";;
+                                 # Guess yes on musl systems.
+           *-musl*)              gl_cv_func_snprintf_retval_c99="guessing yes";;
+                                 # Guess yes on FreeBSD >= 5.
+           freebsd[1-4].*)       gl_cv_func_snprintf_retval_c99="guessing no";;
+           freebsd* | kfreebsd*) gl_cv_func_snprintf_retval_c99="guessing yes";;
+                                 # Guess yes on Mac OS X >= 10.3.
+           darwin[1-6].*)        gl_cv_func_snprintf_retval_c99="guessing no";;
+           darwin*)              gl_cv_func_snprintf_retval_c99="guessing yes";;
+                                 # Guess yes on OpenBSD >= 3.9.
+           openbsd[1-2].* | openbsd3.[0-8] | openbsd3.[0-8].*)
+                                 gl_cv_func_snprintf_retval_c99="guessing no";;
+           openbsd*)             gl_cv_func_snprintf_retval_c99="guessing yes";;
+                                 # Guess yes on Solaris >= 2.10.
+           solaris2.[1-9][0-9]*) gl_cv_func_printf_sizes_c99="guessing yes";;
+           solaris*)             gl_cv_func_printf_sizes_c99="guessing no";;
+                                 # Guess yes on AIX >= 4.
+           aix[1-3]*)            gl_cv_func_snprintf_retval_c99="guessing no";;
+           aix*)                 gl_cv_func_snprintf_retval_c99="guessing yes";;
+                                 # Guess yes on NetBSD >= 3.
+           netbsd[1-2]* | netbsdelf[1-2]* | netbsdaout[1-2]* | netbsdcoff[1-2]*)
+                                 gl_cv_func_snprintf_retval_c99="guessing no";;
+           netbsd*)              gl_cv_func_snprintf_retval_c99="guessing yes";;
+                                 # Guess yes on BeOS.
+           beos*)                gl_cv_func_snprintf_retval_c99="guessing yes";;
+                                 # Guess yes on Android.
+           linux*-android*)      gl_cv_func_snprintf_retval_c99="guessing yes";;
+changequote([,])dnl
+                                 # Guess yes on MSVC, no on mingw.
+           mingw*)               AC_EGREP_CPP([Known], [
+#ifdef _MSC_VER
+ Known
+#endif
+                                   ],
+                                   [gl_cv_func_snprintf_retval_c99="guessing yes"],
+                                   [gl_cv_func_snprintf_retval_c99="guessing no"])
+                                 ;;
+                                 # If we don't know, obey --enable-cross-guesses.
+           *)                    gl_cv_func_snprintf_retval_c99="$gl_cross_guess_normal";;
+         esac
+        ])
+    ])
+])
+
+dnl Test whether the snprintf function supports the %n format directive
+dnl also in truncated portions of the format string. (ISO C99, POSIX:2001)
+dnl Result is gl_cv_func_snprintf_directive_n.
+
+AC_DEFUN([gl_SNPRINTF_DIRECTIVE_N],
+[
+  AC_REQUIRE([AC_PROG_CC])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_REQUIRE([gl_SNPRINTF_PRESENCE])
+  AC_CACHE_CHECK([whether snprintf fully supports the 'n' directive],
+    [gl_cv_func_snprintf_directive_n],
+    [
+      AC_RUN_IFELSE(
+        [AC_LANG_SOURCE([[
+#include <stdio.h>
+#include <string.h>
+#if HAVE_SNPRINTF
+# define my_snprintf snprintf
+#else
+# include <stdarg.h>
+static int my_snprintf (char *buf, int size, const char *format, ...)
+{
+  va_list args;
+  int ret;
+  va_start (args, format);
+  ret = vsnprintf (buf, size, format, args);
+  va_end (args);
+  return ret;
+}
+#endif
+static char fmtstring[10];
+static char buf[100];
+int main ()
+{
+  int count = -1;
+  /* Copy the format string.  Some systems (glibc with _FORTIFY_SOURCE=2)
+     support %n in format strings in read-only memory but not in writable
+     memory.  */
+  strcpy (fmtstring, "%d %n");
+  my_snprintf (buf, 4, fmtstring, 12345, &count, 33, 44, 55);
+  if (count != 6)
+    return 1;
+  return 0;
+}]])],
+        [gl_cv_func_snprintf_directive_n=yes],
+        [gl_cv_func_snprintf_directive_n=no],
+        [
+         case "$host_os" in
+                                 # Guess no on glibc when _FORTIFY_SOURCE >= 2.
+           *-gnu* | gnu*)        AC_COMPILE_IFELSE(
+                                   [AC_LANG_SOURCE(
+                                      [[#if _FORTIFY_SOURCE >= 2
+                                         error fail
+                                        #endif
+                                      ]])],
+                                   [gl_cv_func_snprintf_directive_n="guessing yes"],
+                                   [gl_cv_func_snprintf_directive_n="guessing no"])
+                                 ;;
+changequote(,)dnl
+                                 # Guess yes on musl systems.
+           *-musl*)              gl_cv_func_snprintf_directive_n="guessing yes";;
+                                 # Guess yes on FreeBSD >= 5.
+           freebsd[1-4].*)       gl_cv_func_snprintf_directive_n="guessing no";;
+           freebsd* | kfreebsd*) gl_cv_func_snprintf_directive_n="guessing yes";;
+                                 # Guess yes on Mac OS X >= 10.3.
+           darwin[1-6].*)        gl_cv_func_snprintf_directive_n="guessing no";;
+           darwin*)              gl_cv_func_snprintf_directive_n="guessing yes";;
+                                 # Guess yes on Solaris >= 2.6.
+           solaris2.[0-5] | solaris2.[0-5].*)
+                                 gl_cv_func_snprintf_directive_n="guessing no";;
+           solaris*)             gl_cv_func_snprintf_directive_n="guessing yes";;
+                                 # Guess yes on AIX >= 4.
+           aix[1-3]*)            gl_cv_func_snprintf_directive_n="guessing no";;
+           aix*)                 gl_cv_func_snprintf_directive_n="guessing yes";;
+                                 # Guess yes on IRIX >= 6.5.
+           irix6.5)              gl_cv_func_snprintf_directive_n="guessing yes";;
+                                 # Guess yes on OSF/1 >= 5.
+           osf[3-4]*)            gl_cv_func_snprintf_directive_n="guessing no";;
+           osf*)                 gl_cv_func_snprintf_directive_n="guessing yes";;
+                                 # Guess yes on NetBSD >= 3.
+           netbsd[1-2]* | netbsdelf[1-2]* | netbsdaout[1-2]* | netbsdcoff[1-2]*)
+                                 gl_cv_func_snprintf_directive_n="guessing no";;
+           netbsd*)              gl_cv_func_snprintf_directive_n="guessing yes";;
+                                 # Guess yes on BeOS.
+           beos*)                gl_cv_func_snprintf_directive_n="guessing yes";;
+                                 # Guess no on Android.
+           linux*-android*)      gl_cv_func_snprintf_directive_n="guessing no";;
+                                 # Guess no on native Windows.
+           mingw*)               gl_cv_func_snprintf_directive_n="guessing no";;
+                                 # If we don't know, obey --enable-cross-guesses.
+           *)                    gl_cv_func_snprintf_directive_n="$gl_cross_guess_normal";;
+changequote([,])dnl
+         esac
+        ])
+    ])
+])
+
+dnl Test whether the snprintf function, when passed a size = 1, writes any
+dnl output without bounds in this case, behaving like sprintf. This is the
+dnl case on Linux libc5.
+dnl Result is gl_cv_func_snprintf_size1.
+
+AC_DEFUN([gl_SNPRINTF_SIZE1],
+[
+  AC_REQUIRE([AC_PROG_CC])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_REQUIRE([gl_SNPRINTF_PRESENCE])
+  AC_CACHE_CHECK([whether snprintf respects a size of 1],
+    [gl_cv_func_snprintf_size1],
+    [
+      AC_RUN_IFELSE(
+        [AC_LANG_SOURCE([[
+#include <stdio.h>
+#if HAVE_SNPRINTF
+# define my_snprintf snprintf
+#else
+# include <stdarg.h>
+static int my_snprintf (char *buf, int size, const char *format, ...)
+{
+  va_list args;
+  int ret;
+  va_start (args, format);
+  ret = vsnprintf (buf, size, format, args);
+  va_end (args);
+  return ret;
+}
+#endif
+int main()
+{
+  static char buf[8] = { 'D', 'E', 'A', 'D', 'B', 'E', 'E', 'F' };
+  my_snprintf (buf, 1, "%d", 12345);
+  return buf[1] != 'E';
+}]])],
+        [gl_cv_func_snprintf_size1=yes],
+        [gl_cv_func_snprintf_size1=no],
+        [case "$host_os" in
+                            # Guess yes on Android.
+           linux*-android*) gl_cv_func_snprintf_size1="guessing yes" ;;
+                            # Guess yes on native Windows.
+           mingw*)          gl_cv_func_snprintf_size1="guessing yes" ;;
+           *)               gl_cv_func_snprintf_size1="guessing yes" ;;
+         esac
+        ])
+    ])
+])
+
+dnl Test whether the vsnprintf function, when passed a zero size, produces no
+dnl output. (ISO C99, POSIX:2001)
+dnl For example, snprintf nevertheless writes a NUL byte in this case
+dnl on OSF/1 5.1:
+dnl     ---------------------------------------------------------------------
+dnl     #include <stdio.h>
+dnl     int main()
+dnl     {
+dnl       static char buf[8] = { 'D', 'E', 'A', 'D', 'B', 'E', 'E', 'F' };
+dnl       snprintf (buf, 0, "%d", 12345);
+dnl       return buf[0] != 'D';
+dnl     }
+dnl     ---------------------------------------------------------------------
+dnl And vsnprintf writes any output without bounds in this case, behaving like
+dnl vsprintf, on HP-UX 11 and OSF/1 5.1:
+dnl     ---------------------------------------------------------------------
+dnl     #include <stdarg.h>
+dnl     #include <stdio.h>
+dnl     static int my_snprintf (char *buf, int size, const char *format, ...)
+dnl     {
+dnl       va_list args;
+dnl       int ret;
+dnl       va_start (args, format);
+dnl       ret = vsnprintf (buf, size, format, args);
+dnl       va_end (args);
+dnl       return ret;
+dnl     }
+dnl     int main()
+dnl     {
+dnl       static char buf[8] = { 'D', 'E', 'A', 'D', 'B', 'E', 'E', 'F' };
+dnl       my_snprintf (buf, 0, "%d", 12345);
+dnl       return buf[0] != 'D';
+dnl     }
+dnl     ---------------------------------------------------------------------
+dnl Result is gl_cv_func_vsnprintf_zerosize_c99.
+
+AC_DEFUN([gl_VSNPRINTF_ZEROSIZE_C99],
+[
+  AC_REQUIRE([AC_PROG_CC])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_CACHE_CHECK([whether vsnprintf respects a zero size as in C99],
+    [gl_cv_func_vsnprintf_zerosize_c99],
+    [
+      AC_RUN_IFELSE(
+        [AC_LANG_SOURCE([[
+#include <stdarg.h>
+#include <stdio.h>
+static int my_snprintf (char *buf, int size, const char *format, ...)
+{
+  va_list args;
+  int ret;
+  va_start (args, format);
+  ret = vsnprintf (buf, size, format, args);
+  va_end (args);
+  return ret;
+}
+int main()
+{
+  static char buf[8] = { 'D', 'E', 'A', 'D', 'B', 'E', 'E', 'F' };
+  my_snprintf (buf, 0, "%d", 12345);
+  return buf[0] != 'D';
+}]])],
+        [gl_cv_func_vsnprintf_zerosize_c99=yes],
+        [gl_cv_func_vsnprintf_zerosize_c99=no],
+        [
+changequote(,)dnl
+         case "$host_os" in
+                                 # Guess yes on glibc systems.
+           *-gnu* | gnu*)        gl_cv_func_vsnprintf_zerosize_c99="guessing yes";;
+                                 # Guess yes on musl systems.
+           *-musl*)              gl_cv_func_vsnprintf_zerosize_c99="guessing yes";;
+                                 # Guess yes on FreeBSD >= 5.
+           freebsd[1-4].*)       gl_cv_func_vsnprintf_zerosize_c99="guessing no";;
+           freebsd* | kfreebsd*) gl_cv_func_vsnprintf_zerosize_c99="guessing yes";;
+                                 # Guess yes on Mac OS X >= 10.3.
+           darwin[1-6].*)        gl_cv_func_vsnprintf_zerosize_c99="guessing no";;
+           darwin*)              gl_cv_func_vsnprintf_zerosize_c99="guessing yes";;
+                                 # Guess yes on Cygwin.
+           cygwin*)              gl_cv_func_vsnprintf_zerosize_c99="guessing yes";;
+                                 # Guess yes on Solaris >= 2.6.
+           solaris2.[0-5] | solaris2.[0-5].*)
+                                 gl_cv_func_vsnprintf_zerosize_c99="guessing no";;
+           solaris*)             gl_cv_func_vsnprintf_zerosize_c99="guessing yes";;
+                                 # Guess yes on AIX >= 4.
+           aix[1-3]*)            gl_cv_func_vsnprintf_zerosize_c99="guessing no";;
+           aix*)                 gl_cv_func_vsnprintf_zerosize_c99="guessing yes";;
+                                 # Guess yes on IRIX >= 6.5.
+           irix6.5)              gl_cv_func_vsnprintf_zerosize_c99="guessing yes";;
+                                 # Guess yes on NetBSD >= 3.
+           netbsd[1-2]* | netbsdelf[1-2]* | netbsdaout[1-2]* | netbsdcoff[1-2]*)
+                                 gl_cv_func_vsnprintf_zerosize_c99="guessing no";;
+           netbsd*)              gl_cv_func_vsnprintf_zerosize_c99="guessing yes";;
+                                 # Guess yes on BeOS.
+           beos*)                gl_cv_func_vsnprintf_zerosize_c99="guessing yes";;
+                                 # Guess yes on Android.
+           linux*-android*)      gl_cv_func_vsnprintf_zerosize_c99="guessing yes";;
+                                 # Guess yes on native Windows.
+           mingw* | pw*)         gl_cv_func_vsnprintf_zerosize_c99="guessing yes";;
+                                 # If we don't know, obey --enable-cross-guesses.
+           *)                    gl_cv_func_vsnprintf_zerosize_c99="$gl_cross_guess_normal";;
+         esac
+changequote([,])dnl
+        ])
+    ])
+])
+
+dnl The results of these tests on various platforms are:
+dnl
+dnl 1 = gl_PRINTF_SIZES_C99
+dnl 2 = gl_PRINTF_LONG_DOUBLE
+dnl 3 = gl_PRINTF_INFINITE
+dnl 4 = gl_PRINTF_INFINITE_LONG_DOUBLE
+dnl 5 = gl_PRINTF_DIRECTIVE_A
+dnl 6 = gl_PRINTF_DIRECTIVE_F
+dnl 7 = gl_PRINTF_DIRECTIVE_N
+dnl 8 = gl_PRINTF_DIRECTIVE_LS
+dnl 9 = gl_PRINTF_POSITIONS
+dnl 10 = gl_PRINTF_FLAG_GROUPING
+dnl 11 = gl_PRINTF_FLAG_LEFTADJUST
+dnl 12 = gl_PRINTF_FLAG_ZERO
+dnl 13 = gl_PRINTF_PRECISION
+dnl 14 = gl_PRINTF_ENOMEM
+dnl 15 = gl_SNPRINTF_PRESENCE
+dnl 16 = gl_SNPRINTF_TRUNCATION_C99
+dnl 17 = gl_SNPRINTF_RETVAL_C99
+dnl 18 = gl_SNPRINTF_DIRECTIVE_N
+dnl 19 = gl_SNPRINTF_SIZE1
+dnl 20 = gl_VSNPRINTF_ZEROSIZE_C99
+dnl
+dnl 1 = checking whether printf supports size specifiers as in C99...
+dnl 2 = checking whether printf supports 'long double' arguments...
+dnl 3 = checking whether printf supports infinite 'double' arguments...
+dnl 4 = checking whether printf supports infinite 'long double' arguments...
+dnl 5 = checking whether printf supports the 'a' and 'A' directives...
+dnl 6 = checking whether printf supports the 'F' directive...
+dnl 7 = checking whether printf supports the 'n' directive...
+dnl 8 = checking whether printf supports the 'ls' directive...
+dnl 9 = checking whether printf supports POSIX/XSI format strings with positions...
+dnl 10 = checking whether printf supports the grouping flag...
+dnl 11 = checking whether printf supports the left-adjust flag correctly...
+dnl 12 = checking whether printf supports the zero flag correctly...
+dnl 13 = checking whether printf supports large precisions...
+dnl 14 = checking whether printf survives out-of-memory conditions...
+dnl 15 = checking for snprintf...
+dnl 16 = checking whether snprintf truncates the result as in C99...
+dnl 17 = checking whether snprintf returns a byte count as in C99...
+dnl 18 = checking whether snprintf fully supports the 'n' directive...
+dnl 19 = checking whether snprintf respects a size of 1...
+dnl 20 = checking whether vsnprintf respects a zero size as in C99...
+dnl
+dnl . = yes, # = no.
+dnl
+dnl                                  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 16 17 18 19 20
+dnl   glibc 2.5                      .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .
+dnl   glibc 2.3.6                    .  .  .  .  #  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .
+dnl   FreeBSD 5.4, 6.1               .  .  .  .  #  .  .  .  .  .  .  #  .  #  .  .  .  .  .  .
+dnl   Mac OS X 10.13.5               .  .  .  #  #  .  #  .  .  .  .  .  .  .  .  .  .  #  .  .
+dnl   Mac OS X 10.5.8                .  .  .  #  #  .  .  .  .  .  .  #  .  .  .  .  .  .  .  .
+dnl   Mac OS X 10.3.9                .  .  .  .  #  .  .  .  .  .  .  #  .  #  .  .  .  .  .  .
+dnl   OpenBSD 6.0, 6.7               .  .  .  .  #  .  .  .  .  .  .  .  .  #  .  .  .  .  .  .
+dnl   OpenBSD 3.9, 4.0               .  .  #  #  #  #  .  #  .  #  .  #  .  #  .  .  .  .  .  .
+dnl   Cygwin 1.7.0 (2009)            .  .  .  #  .  .  .  ?  .  .  .  .  .  ?  .  .  .  .  .  .
+dnl   Cygwin 1.5.25 (2008)           .  .  .  #  #  .  .  #  .  .  .  .  .  #  .  .  .  .  .  .
+dnl   Cygwin 1.5.19 (2006)           #  .  .  #  #  #  .  #  .  #  .  #  #  #  .  .  .  .  .  .
+dnl   Solaris 11.4                   .  .  #  #  #  .  .  #  .  .  .  #  .  .  .  .  .  .  .  .
+dnl   Solaris 11.3                   .  .  .  .  #  .  .  #  .  .  .  .  .  .  .  .  .  .  .  .
+dnl   Solaris 11.0                   .  .  #  #  #  .  .  #  .  .  .  #  .  .  .  .  .  .  .  .
+dnl   Solaris 10                     .  .  #  #  #  .  .  #  .  .  .  #  #  .  .  .  .  .  .  .
+dnl   Solaris 2.6 ... 9              #  .  #  #  #  #  .  #  .  .  .  #  #  .  .  .  #  .  .  .
+dnl   Solaris 2.5.1                  #  .  #  #  #  #  .  #  .  .  .  #  .  .  #  #  #  #  #  #
+dnl   AIX 7.1                        .  .  #  #  #  .  .  .  .  .  .  #  #  .  .  .  .  .  .  .
+dnl   AIX 5.2                        .  .  #  #  #  .  .  .  .  .  .  #  .  .  .  .  .  .  .  .
+dnl   AIX 4.3.2, 5.1                 #  .  #  #  #  #  .  .  .  .  .  #  .  .  .  .  #  .  .  .
+dnl   HP-UX 11.31                    .  .  .  .  #  .  .  .  .  .  .  #  .  .  .  .  #  #  .  .
+dnl   HP-UX 11.{00,11,23}            #  .  .  .  #  #  .  .  .  .  .  #  .  .  .  .  #  #  .  #
+dnl   HP-UX 10.20                    #  .  #  .  #  #  .  ?  .  .  #  #  .  .  .  .  #  #  ?  #
+dnl   IRIX 6.5                       #  .  #  #  #  #  .  #  .  .  .  #  .  .  .  .  #  .  .  .
+dnl   OSF/1 5.1                      #  .  #  #  #  #  .  .  .  .  .  #  .  .  .  .  #  .  .  #
+dnl   OSF/1 4.0d                     #  .  #  #  #  #  .  .  .  .  .  #  .  .  #  #  #  #  #  #
+dnl   NetBSD 9.0                     .  .  .  .  #  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .
+dnl   NetBSD 5.0                     .  .  .  #  #  .  .  .  .  .  .  #  .  #  .  .  .  .  .  .
+dnl   NetBSD 4.0                     .  ?  ?  ?  ?  ?  .  ?  .  ?  ?  ?  ?  ?  .  .  .  ?  ?  ?
+dnl   NetBSD 3.0                     .  .  .  .  #  #  .  ?  #  #  ?  #  .  #  .  .  .  .  .  .
+dnl   Haiku                          .  .  .  #  #  #  .  #  .  .  .  .  .  ?  .  .  ?  .  .  .
+dnl   BeOS                           #  #  .  #  #  #  .  ?  #  .  ?  .  #  ?  .  .  ?  .  .  .
+dnl   Android 4.3                    .  .  #  #  #  #  #  #  .  #  .  #  .  #  .  .  .  #  .  .
+dnl   old mingw / msvcrt             #  #  #  #  #  #  .  .  #  #  .  #  #  ?  .  #  #  #  .  .
+dnl   MSVC 9                         #  #  #  #  #  #  #  .  #  #  .  #  #  ?  #  #  #  #  .  .
+dnl   mingw 2009-2011                .  #  .  #  .  .  .  .  #  #  .  .  .  ?  .  .  .  .  .  .
+dnl   mingw-w64 2011                 #  #  #  #  #  #  .  .  #  #  .  #  #  ?  .  #  #  #  .  .
diff --git a/m4/pthread_rwlock_rdlock.m4 b/m4/pthread_rwlock_rdlock.m4
new file mode 100644
index 0000000..049af50
--- /dev/null
+++ b/m4/pthread_rwlock_rdlock.m4
@@ -0,0 +1,185 @@
+# pthread_rwlock_rdlock.m4 serial 4
+dnl Copyright (C) 2017-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl From Bruno Haible.
+dnl Inspired by
+dnl https://github.com/linux-test-project/ltp/blob/master/testcases/open_posix_testsuite/conformance/interfaces/pthread_rwlock_rdlock/2-2.c
+dnl by Intel Corporation.
+
+dnl Test whether in a situation where
+dnl   - an rwlock is taken by a reader and has a writer waiting,
+dnl   - an additional reader requests the lock,
+dnl   - the waiting writer and the requesting reader threads have the same
+dnl     priority,
+dnl the requesting reader thread gets blocked, so that at some point the
+dnl waiting writer can acquire the lock.
+dnl Without such a guarantee, when there a N readers and each of the readers
+dnl spends more than 1/Nth of the time with the lock held, there is a high
+dnl probability that the waiting writer will not get the lock in a given finite
+dnl time, a phenomenon called "writer starvation".
+dnl Without such a guarantee, applications have a hard time avoiding writer
+dnl starvation.
+dnl
+dnl POSIX:2017 makes this requirement only for implementations that support TPS
+dnl (Thread Priority Scheduling) and only for the scheduling policies SCHED_FIFO
+dnl and SCHED_RR, see
+dnl https://pubs.opengroup.org/onlinepubs/9699919799/functions/pthread_rwlock_rdlock.html
+dnl but this test verifies the guarantee regardless of TPS and regardless of
+dnl scheduling policy.
+dnl Glibc does not provide this guarantee (and never will on Linux), see
+dnl https://sourceware.org/bugzilla/show_bug.cgi?id=13701
+dnl https://bugzilla.redhat.com/show_bug.cgi?id=1410052
+AC_DEFUN([gl_PTHREAD_RWLOCK_RDLOCK_PREFER_WRITER],
+[
+  AC_REQUIRE([gl_THREADLIB_EARLY])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_CACHE_CHECK([whether pthread_rwlock_rdlock prefers a writer to a reader],
+    [gl_cv_pthread_rwlock_rdlock_prefer_writer],
+    [save_LIBS="$LIBS"
+     LIBS="$LIBS $LIBMULTITHREAD"
+     AC_RUN_IFELSE(
+       [AC_LANG_SOURCE([[
+#include <errno.h>
+#include <pthread.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#define SUCCEED() exit (0)
+#define FAILURE() exit (1)
+#define UNEXPECTED(n) (exit (10 + (n)))
+
+/* The main thread creates the waiting writer and the requesting reader threads
+   in the default way; this guarantees that they have the same priority.
+   We can reuse the main thread as first reader thread.  */
+
+static pthread_rwlock_t lock;
+static pthread_t reader1;
+static pthread_t writer;
+static pthread_t reader2;
+static pthread_t timer;
+/* Used to pass control from writer to reader2 and from reader2 to timer,
+   as in a relay race.
+   Passing control from one running thread to another running thread
+   is most likely faster than to create the second thread.  */
+static pthread_mutex_t baton;
+
+static void *
+timer_func (void *ignored)
+{
+  /* Step 13 (can be before or after step 12):
+     The timer thread takes the baton, then waits a moment to make sure
+     it can tell whether the second reader thread is blocked at step 12.  */
+  if (pthread_mutex_lock (&baton))
+    UNEXPECTED (13);
+  usleep (100000);
+  /* By the time we get here, it's clear that the second reader thread is
+     blocked at step 12.  This is the desired behaviour.  */
+  SUCCEED ();
+}
+
+static void *
+reader2_func (void *ignored)
+{
+  int err;
+
+  /* Step 8 (can be before or after step 7):
+     The second reader thread takes the baton, then waits a moment to make sure
+     the writer thread has reached step 7.  */
+  if (pthread_mutex_lock (&baton))
+    UNEXPECTED (8);
+  usleep (100000);
+  /* Step 9: The second reader thread requests the lock.  */
+  err = pthread_rwlock_tryrdlock (&lock);
+  if (err == 0)
+    FAILURE ();
+  else if (err != EBUSY)
+    UNEXPECTED (9);
+  /* Step 10: Launch a timer, to test whether the next call blocks.  */
+  if (pthread_create (&timer, NULL, timer_func, NULL))
+    UNEXPECTED (10);
+  /* Step 11: Release the baton.  */
+  if (pthread_mutex_unlock (&baton))
+    UNEXPECTED (11);
+  /* Step 12: The second reader thread requests the lock.  */
+  err = pthread_rwlock_rdlock (&lock);
+  if (err == 0)
+    FAILURE ();
+  else
+    UNEXPECTED (12);
+}
+
+static void *
+writer_func (void *ignored)
+{
+  /* Step 4: Take the baton, so that the second reader thread does not go ahead
+     too early.  */
+  if (pthread_mutex_lock (&baton))
+    UNEXPECTED (4);
+  /* Step 5: Create the second reader thread.  */
+  if (pthread_create (&reader2, NULL, reader2_func, NULL))
+    UNEXPECTED (5);
+  /* Step 6: Release the baton.  */
+  if (pthread_mutex_unlock (&baton))
+    UNEXPECTED (6);
+  /* Step 7: The writer thread requests the lock.  */
+  if (pthread_rwlock_wrlock (&lock))
+    UNEXPECTED (7);
+  return NULL;
+}
+
+int
+main ()
+{
+  reader1 = pthread_self ();
+
+  /* Step 1: The main thread initializes the lock and the baton.  */
+  if (pthread_rwlock_init (&lock, NULL))
+    UNEXPECTED (1);
+  if (pthread_mutex_init (&baton, NULL))
+    UNEXPECTED (1);
+  /* Step 2: The main thread acquires the lock as a reader.  */
+  if (pthread_rwlock_rdlock (&lock))
+    UNEXPECTED (2);
+  /* Step 3: Create the writer thread.  */
+  if (pthread_create (&writer, NULL, writer_func, NULL))
+    UNEXPECTED (3);
+  /* Job done.  Go to sleep.  */
+  for (;;)
+    {
+      sleep (1);
+    }
+}
+]])],
+       [gl_cv_pthread_rwlock_rdlock_prefer_writer=yes],
+       [gl_cv_pthread_rwlock_rdlock_prefer_writer=no],
+       [case "$host_os" in
+                         # Guess no on glibc systems.
+          *-gnu* | gnu*) gl_cv_pthread_rwlock_rdlock_prefer_writer="guessing no" ;;
+                         # Guess no on musl systems.
+          *-musl*)       gl_cv_pthread_rwlock_rdlock_prefer_writer="guessing no" ;;
+                         # Guess no on bionic systems.
+          *-android*)    gl_cv_pthread_rwlock_rdlock_prefer_writer="guessing no" ;;
+                         # Guess yes on native Windows with the mingw-w64 winpthreads library.
+                         # Guess no on native Windows with the gnulib windows-rwlock module.
+          mingw*)        if test "$gl_use_threads" = yes || test "$gl_use_threads" = posix; then
+                           gl_cv_pthread_rwlock_rdlock_prefer_writer="guessing yes"
+                         else
+                           gl_cv_pthread_rwlock_rdlock_prefer_writer="guessing no"
+                         fi
+                         ;;
+                         # If we don't know, obey --enable-cross-guesses.
+          *)             gl_cv_pthread_rwlock_rdlock_prefer_writer="$gl_cross_guess_normal" ;;
+         esac
+       ])
+     LIBS="$save_LIBS"
+    ])
+  case "$gl_cv_pthread_rwlock_rdlock_prefer_writer" in
+    *yes)
+      AC_DEFINE([HAVE_PTHREAD_RWLOCK_RDLOCK_PREFER_WRITER], [1],
+        [Define if the 'pthread_rwlock_rdlock' function prefers a writer to a reader.])
+      ;;
+  esac
+])
diff --git a/m4/quote.m4 b/m4/quote.m4
new file mode 100644
index 0000000..9efab95
--- /dev/null
+++ b/m4/quote.m4
@@ -0,0 +1,13 @@
+# quote.m4 serial 6
+dnl Copyright (C) 2002-2003, 2005-2006, 2009-2020 Free Software Foundation,
+dnl Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_QUOTE],
+[
+  dnl Prerequisites of lib/quote.c.
+  dnl (none)
+  :
+])
diff --git a/m4/quotearg.m4 b/m4/quotearg.m4
new file mode 100644
index 0000000..4038711
--- /dev/null
+++ b/m4/quotearg.m4
@@ -0,0 +1,11 @@
+# quotearg.m4 serial 10
+dnl Copyright (C) 2002, 2004-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_QUOTEARG],
+[
+  AC_REQUIRE([AC_C_RESTRICT])
+  :
+])
diff --git a/m4/raise.m4 b/m4/raise.m4
new file mode 100644
index 0000000..5b61b65
--- /dev/null
+++ b/m4/raise.m4
@@ -0,0 +1,36 @@
+# raise.m4 serial 4
+dnl Copyright (C) 2011-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_RAISE],
+[
+  AC_REQUIRE([gl_SIGNAL_H_DEFAULTS])
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  AC_CHECK_FUNCS([raise])
+  if test $ac_cv_func_raise = no; then
+    HAVE_RAISE=0
+  else
+    m4_ifdef([gl_MSVC_INVAL], [
+      AC_REQUIRE([gl_MSVC_INVAL])
+      if test $HAVE_MSVC_INVALID_PARAMETER_HANDLER = 1; then
+        REPLACE_RAISE=1
+      fi
+    ])
+    m4_ifdef([gl_SIGNALBLOCKING], [
+      gl_SIGNALBLOCKING
+      if test $HAVE_POSIX_SIGNALBLOCKING = 0; then
+        m4_ifdef([gl_SIGNAL_SIGPIPE], [
+          gl_SIGNAL_SIGPIPE
+          if test $gl_cv_header_signal_h_SIGPIPE != yes; then
+            REPLACE_RAISE=1
+          fi
+        ], [:])
+      fi
+    ])
+  fi
+])
+
+# Prerequisites of lib/raise.c.
+AC_DEFUN([gl_PREREQ_RAISE], [:])
diff --git a/m4/rawmemchr.m4 b/m4/rawmemchr.m4
new file mode 100644
index 0000000..c5bf041
--- /dev/null
+++ b/m4/rawmemchr.m4
@@ -0,0 +1,20 @@
+# rawmemchr.m4 serial 2
+dnl Copyright (C) 2003, 2007-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_RAWMEMCHR],
+[
+  dnl Persuade glibc <string.h> to declare rawmemchr().
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
+
+  AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS])
+  AC_CHECK_FUNCS([rawmemchr])
+  if test $ac_cv_func_rawmemchr = no; then
+    HAVE_RAWMEMCHR=0
+  fi
+])
+
+# Prerequisites of lib/strchrnul.c.
+AC_DEFUN([gl_PREREQ_RAWMEMCHR], [:])
diff --git a/m4/readdir.m4 b/m4/readdir.m4
new file mode 100644
index 0000000..ca4e741
--- /dev/null
+++ b/m4/readdir.m4
@@ -0,0 +1,15 @@
+# readdir.m4 serial 1
+dnl Copyright (C) 2011-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_READDIR],
+[
+  AC_REQUIRE([gl_DIRENT_H_DEFAULTS])
+
+  AC_CHECK_FUNCS([readdir])
+  if test $ac_cv_func_readdir = no; then
+    HAVE_READDIR=0
+  fi
+])
diff --git a/m4/readlink.m4 b/m4/readlink.m4
new file mode 100644
index 0000000..c7f436a
--- /dev/null
+++ b/m4/readlink.m4
@@ -0,0 +1,114 @@
+# readlink.m4 serial 16
+dnl Copyright (C) 2003, 2007, 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_READLINK],
+[
+  AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_CHECK_FUNCS_ONCE([readlink])
+  if test $ac_cv_func_readlink = no; then
+    HAVE_READLINK=0
+  else
+    AC_CACHE_CHECK([whether readlink signature is correct],
+      [gl_cv_decl_readlink_works],
+      [AC_COMPILE_IFELSE(
+         [AC_LANG_PROGRAM(
+           [[#include <unistd.h>
+      /* Cause compilation failure if original declaration has wrong type.  */
+      ssize_t readlink (const char *, char *, size_t);]])],
+         [gl_cv_decl_readlink_works=yes], [gl_cv_decl_readlink_works=no])])
+    dnl Solaris 9 ignores trailing slash.
+    dnl FreeBSD 7.2 dereferences only one level of links with trailing slash.
+    AC_CACHE_CHECK([whether readlink handles trailing slash correctly],
+      [gl_cv_func_readlink_trailing_slash],
+      [# We have readlink, so assume ln -s works.
+       ln -s conftest.no-such conftest.link
+       ln -s conftest.link conftest.lnk2
+       AC_RUN_IFELSE(
+         [AC_LANG_PROGRAM(
+           [[#include <unistd.h>
+]], [[char buf[20];
+      return readlink ("conftest.lnk2/", buf, sizeof buf) != -1;]])],
+         [gl_cv_func_readlink_trailing_slash=yes],
+         [gl_cv_func_readlink_trailing_slash=no],
+         [case "$host_os" in
+            # Guess yes on Linux or glibc systems.
+            linux-* | linux | *-gnu* | gnu*)
+              gl_cv_func_readlink_trailing_slash="guessing yes" ;;
+            # Guess no on AIX or HP-UX.
+            aix* | hpux*)
+              gl_cv_func_readlink_trailing_slash="guessing no" ;;
+            # If we don't know, obey --enable-cross-guesses.
+            *)
+              gl_cv_func_readlink_trailing_slash="$gl_cross_guess_normal" ;;
+          esac
+         ])
+      rm -f conftest.link conftest.lnk2])
+    case "$gl_cv_func_readlink_trailing_slash" in
+      *yes)
+        if test "$gl_cv_decl_readlink_works" != yes; then
+          REPLACE_READLINK=1
+        fi
+        ;;
+      *)
+        AC_DEFINE([READLINK_TRAILING_SLASH_BUG], [1], [Define to 1 if readlink
+          fails to recognize a trailing slash.])
+        REPLACE_READLINK=1
+        ;;
+    esac
+
+    AC_CACHE_CHECK([whether readlink truncates results correctly],
+      [gl_cv_func_readlink_truncate],
+      [# We have readlink, so assume ln -s works.
+       ln -s ab conftest.link
+       AC_RUN_IFELSE(
+         [AC_LANG_PROGRAM(
+           [[#include <unistd.h>
+]], [[char c;
+      return readlink ("conftest.link", &c, 1) != 1;]])],
+         [gl_cv_func_readlink_truncate=yes],
+         [gl_cv_func_readlink_truncate=no],
+         [case "$host_os" in
+            # Guess yes on Linux or glibc systems.
+            linux-* | linux | *-gnu* | gnu*)
+              gl_cv_func_readlink_truncate="guessing yes" ;;
+            # Guess no on AIX or HP-UX.
+            aix* | hpux*)
+              gl_cv_func_readlink_truncate="guessing no" ;;
+            # If we don't know, obey --enable-cross-guesses.
+            *)
+              gl_cv_func_readlink_truncate="$gl_cross_guess_normal" ;;
+          esac
+         ])
+      rm -f conftest.link conftest.lnk2])
+    case $gl_cv_func_readlink_truncate in
+      *yes)
+        if test "$gl_cv_decl_readlink_works" != yes; then
+          REPLACE_READLINK=1
+        fi
+        ;;
+      *)
+        AC_DEFINE([READLINK_TRUNCATE_BUG], [1], [Define to 1 if readlink
+          sets errno instead of truncating a too-long link.])
+        REPLACE_READLINK=1
+        ;;
+    esac
+  fi
+])
+
+# Like gl_FUNC_READLINK, except prepare for separate compilation
+# (no REPLACE_READLINK, no AC_LIBOBJ).
+AC_DEFUN([gl_FUNC_READLINK_SEPARATE],
+[
+  AC_CHECK_FUNCS_ONCE([readlink])
+  gl_PREREQ_READLINK
+])
+
+# Prerequisites of lib/readlink.c.
+AC_DEFUN([gl_PREREQ_READLINK],
+[
+  :
+])
diff --git a/m4/realloc.m4 b/m4/realloc.m4
new file mode 100644
index 0000000..53967f4
--- /dev/null
+++ b/m4/realloc.m4
@@ -0,0 +1,76 @@
+# realloc.m4 serial 19
+dnl Copyright (C) 2007, 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+# This is adapted with modifications from upstream Autoconf here:
+# https://git.savannah.gnu.org/cgit/autoconf.git/commit/?id=04be2b7a29d65d9a08e64e8e56e594c91749598c
+AC_DEFUN([_AC_FUNC_REALLOC_IF],
+[
+  AC_REQUIRE([AC_CANONICAL_HOST])dnl for cross-compiles
+  AC_CACHE_CHECK([for GNU libc compatible realloc],
+    [ac_cv_func_realloc_0_nonnull],
+    [AC_RUN_IFELSE(
+       [AC_LANG_PROGRAM(
+          [[#include <stdlib.h>
+          ]],
+          [[char *p = realloc (0, 0);
+            int result = !p;
+            free (p);
+            return result;]])
+       ],
+       [ac_cv_func_realloc_0_nonnull=yes],
+       [ac_cv_func_realloc_0_nonnull=no],
+       [case "$host_os" in
+          # Guess yes on platforms where we know the result.
+          *-gnu* | gnu* | *-musl* | freebsd* | netbsd* | openbsd* \
+          | hpux* | solaris* | cygwin* | mingw*)
+            ac_cv_func_realloc_0_nonnull="guessing yes" ;;
+          # If we don't know, obey --enable-cross-guesses.
+          *) ac_cv_func_realloc_0_nonnull="$gl_cross_guess_normal" ;;
+        esac
+       ])
+    ])
+  case "$ac_cv_func_realloc_0_nonnull" in
+    *yes)
+      $1
+      ;;
+    *)
+      $2
+      ;;
+  esac
+])# AC_FUNC_REALLOC
+
+# gl_FUNC_REALLOC_GNU
+# -------------------
+# Test whether 'realloc (0, 0)' is handled like in GNU libc, and replace
+# realloc if it is not.
+AC_DEFUN([gl_FUNC_REALLOC_GNU],
+[
+  AC_REQUIRE([gl_STDLIB_H_DEFAULTS])
+  dnl _AC_FUNC_REALLOC_IF is defined in Autoconf.
+  _AC_FUNC_REALLOC_IF(
+    [AC_DEFINE([HAVE_REALLOC_GNU], [1],
+               [Define to 1 if your system has a GNU libc compatible 'realloc'
+                function, and to 0 otherwise.])],
+    [AC_DEFINE([HAVE_REALLOC_GNU], [0])
+     REPLACE_REALLOC=1
+    ])
+])# gl_FUNC_REALLOC_GNU
+
+# gl_FUNC_REALLOC_POSIX
+# ---------------------
+# Test whether 'realloc' is POSIX compliant (sets errno to ENOMEM when it
+# fails), and replace realloc if it is not.
+AC_DEFUN([gl_FUNC_REALLOC_POSIX],
+[
+  AC_REQUIRE([gl_STDLIB_H_DEFAULTS])
+  AC_REQUIRE([gl_CHECK_MALLOC_POSIX])
+  if test $gl_cv_func_malloc_posix = yes; then
+    AC_DEFINE([HAVE_REALLOC_POSIX], [1],
+      [Define if the 'realloc' function is POSIX compliant.])
+  else
+    REPLACE_REALLOC=1
+  fi
+])
diff --git a/m4/regex.m4 b/m4/regex.m4
new file mode 100644
index 0000000..effe100
--- /dev/null
+++ b/m4/regex.m4
@@ -0,0 +1,360 @@
+# serial 71
+
+# Copyright (C) 1996-2001, 2003-2020 Free Software Foundation, Inc.
+#
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+dnl Initially derived from code in GNU grep.
+dnl Mostly written by Jim Meyering.
+
+AC_PREREQ([2.50])
+
+AC_DEFUN([gl_REGEX],
+[
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_ARG_WITH([included-regex],
+    [AS_HELP_STRING([--without-included-regex],
+                    [don't compile regex; this is the default on systems
+                     with recent-enough versions of the GNU C Library
+                     (use with caution on other systems).])])
+
+  case $with_included_regex in #(
+  yes|no) ac_use_included_regex=$with_included_regex
+        ;;
+  '')
+    # If the system regex support is good enough that it passes the
+    # following run test, then default to *not* using the included regex.c.
+    # If cross compiling, assume the test would fail and use the included
+    # regex.c.
+    AC_CHECK_DECLS_ONCE([alarm])
+    AC_CHECK_HEADERS_ONCE([malloc.h])
+    AC_CACHE_CHECK([for working re_compile_pattern],
+                   [gl_cv_func_re_compile_pattern_working],
+      [AC_RUN_IFELSE(
+        [AC_LANG_PROGRAM(
+          [[#include <regex.h>
+
+            #include <locale.h>
+            #include <limits.h>
+            #include <string.h>
+
+            #if defined M_CHECK_ACTION || HAVE_DECL_ALARM
+            # include <signal.h>
+            # include <unistd.h>
+            #endif
+
+            #if HAVE_MALLOC_H
+            # include <malloc.h>
+            #endif
+
+            #ifdef M_CHECK_ACTION
+            /* Exit with distinguishable exit code.  */
+            static void sigabrt_no_core (int sig) { raise (SIGTERM); }
+            #endif
+          ]],
+          [[int result = 0;
+            static struct re_pattern_buffer regex;
+            unsigned char folded_chars[UCHAR_MAX + 1];
+            int i;
+            const char *s;
+            struct re_registers regs;
+
+            /* Some builds of glibc go into an infinite loop on this
+               test.  Use alarm to force death, and mallopt to avoid
+               malloc recursion in diagnosing the corrupted heap. */
+#if HAVE_DECL_ALARM
+            signal (SIGALRM, SIG_DFL);
+            alarm (2);
+#endif
+#ifdef M_CHECK_ACTION
+            signal (SIGABRT, sigabrt_no_core);
+            mallopt (M_CHECK_ACTION, 2);
+#endif
+
+            if (setlocale (LC_ALL, "en_US.UTF-8"))
+              {
+                {
+                  /* https://sourceware.org/ml/libc-hacker/2006-09/msg00008.html
+                     This test needs valgrind to catch the bug on Debian
+                     GNU/Linux 3.1 x86, but it might catch the bug better
+                     on other platforms and it shouldn't hurt to try the
+                     test here.  */
+                  static char const pat[] = "insert into";
+                  static char const data[] =
+                    "\xFF\0\x12\xA2\xAA\xC4\xB1,K\x12\xC4\xB1*\xACK";
+                  re_set_syntax (RE_SYNTAX_GREP | RE_HAT_LISTS_NOT_NEWLINE
+                                 | RE_ICASE);
+                  memset (&regex, 0, sizeof regex);
+                  s = re_compile_pattern (pat, sizeof pat - 1, &regex);
+                  if (s)
+                    result |= 1;
+                  else
+                    {
+                      if (re_search (&regex, data, sizeof data - 1,
+                                     0, sizeof data - 1, &regs)
+                          != -1)
+                        result |= 1;
+                      regfree (&regex);
+                    }
+                }
+
+                {
+                  /* This test is from glibc bug 15078.
+                     The test case is from Andreas Schwab in
+                     <https://sourceware.org/ml/libc-alpha/2013-01/msg00967.html>.
+                     */
+                  static char const pat[] = "[^x]x";
+                  static char const data[] =
+                    /* <U1000><U103B><U103D><U1014><U103A><U102F><U1015><U103A> */
+                    "\xe1\x80\x80"
+                    "\xe1\x80\xbb"
+                    "\xe1\x80\xbd"
+                    "\xe1\x80\x94"
+                    "\xe1\x80\xba"
+                    "\xe1\x80\xaf"
+                    "\xe1\x80\x95"
+                    "\xe1\x80\xba"
+                    "x";
+                  re_set_syntax (0);
+                  memset (&regex, 0, sizeof regex);
+                  s = re_compile_pattern (pat, sizeof pat - 1, &regex);
+                  if (s)
+                    result |= 1;
+                  else
+                    {
+                      i = re_search (&regex, data, sizeof data - 1,
+                                     0, sizeof data - 1, 0);
+                      if (i != 0 && i != 21)
+                        result |= 1;
+                      regfree (&regex);
+                    }
+                }
+
+                if (! setlocale (LC_ALL, "C"))
+                  return 1;
+              }
+
+            /* This test is from glibc bug 3957, reported by Andrew Mackey.  */
+            re_set_syntax (RE_SYNTAX_EGREP | RE_HAT_LISTS_NOT_NEWLINE);
+            memset (&regex, 0, sizeof regex);
+            s = re_compile_pattern ("a[^x]b", 6, &regex);
+            if (s)
+              result |= 2;
+            else
+              {
+                /* This should fail, but succeeds for glibc-2.5.  */
+                if (re_search (&regex, "a\nb", 3, 0, 3, &regs) != -1)
+                  result |= 2;
+                regfree (&regex);
+              }
+
+            /* This regular expression is from Spencer ere test number 75
+               in grep-2.3.  */
+            re_set_syntax (RE_SYNTAX_POSIX_EGREP);
+            memset (&regex, 0, sizeof regex);
+            for (i = 0; i <= UCHAR_MAX; i++)
+              folded_chars[i] = i;
+            regex.translate = folded_chars;
+            s = re_compile_pattern ("a[[:@:>@:]]b\n", 11, &regex);
+            /* This should fail with _Invalid character class name_ error.  */
+            if (!s)
+              {
+                result |= 4;
+                regfree (&regex);
+              }
+
+            /* Ensure that [b-a] is diagnosed as invalid, when
+               using RE_NO_EMPTY_RANGES. */
+            re_set_syntax (RE_SYNTAX_POSIX_EGREP | RE_NO_EMPTY_RANGES);
+            memset (&regex, 0, sizeof regex);
+            s = re_compile_pattern ("a[b-a]", 6, &regex);
+            if (s == 0)
+              {
+                result |= 8;
+                regfree (&regex);
+              }
+
+            /* This should succeed, but does not for glibc-2.1.3.  */
+            memset (&regex, 0, sizeof regex);
+            s = re_compile_pattern ("{1", 2, &regex);
+            if (s)
+              result |= 8;
+            else
+              regfree (&regex);
+
+            /* The following example is derived from a problem report
+               against gawk from Jorge Stolfi <stolfi@ic.unicamp.br>.  */
+            memset (&regex, 0, sizeof regex);
+            s = re_compile_pattern ("[an\371]*n", 7, &regex);
+            if (s)
+              result |= 8;
+            else
+              {
+                /* This should match, but does not for glibc-2.2.1.  */
+                if (re_match (&regex, "an", 2, 0, &regs) != 2)
+                  result |= 8;
+                else
+                  {
+                    free (regs.start);
+                    free (regs.end);
+                  }
+                regfree (&regex);
+              }
+
+            memset (&regex, 0, sizeof regex);
+            s = re_compile_pattern ("x", 1, &regex);
+            if (s)
+              result |= 8;
+            else
+              {
+                /* glibc-2.2.93 does not work with a negative RANGE argument.  */
+                if (re_search (&regex, "wxy", 3, 2, -2, &regs) != 1)
+                  result |= 8;
+                else
+                  {
+                    free (regs.start);
+                    free (regs.end);
+                  }
+                regfree (&regex);
+              }
+
+            /* The version of regex.c in older versions of gnulib
+               ignored RE_ICASE.  Detect that problem too.  */
+            re_set_syntax (RE_SYNTAX_EMACS | RE_ICASE);
+            memset (&regex, 0, sizeof regex);
+            s = re_compile_pattern ("x", 1, &regex);
+            if (s)
+              result |= 16;
+            else
+              {
+                if (re_search (&regex, "WXY", 3, 0, 3, &regs) < 0)
+                  result |= 16;
+                else
+                  {
+                    free (regs.start);
+                    free (regs.end);
+                  }
+                regfree (&regex);
+              }
+
+            /* Catch a bug reported by Vin Shelton in
+               https://lists.gnu.org/r/bug-coreutils/2007-06/msg00089.html
+               */
+            re_set_syntax (RE_SYNTAX_POSIX_BASIC
+                           & ~RE_CONTEXT_INVALID_DUP
+                           & ~RE_NO_EMPTY_RANGES);
+            memset (&regex, 0, sizeof regex);
+            s = re_compile_pattern ("[[:alnum:]_-]\\\\+$", 16, &regex);
+            if (s)
+              result |= 32;
+            else
+              regfree (&regex);
+
+            /* REG_STARTEND was added to glibc on 2004-01-15.
+               Reject older versions.  */
+            if (! REG_STARTEND)
+              result |= 64;
+
+            /* Matching with the compiled form of this regexp would provoke
+               an assertion failure prior to glibc-2.28:
+                 regexec.c:1375: pop_fail_stack: Assertion 'num >= 0' failed
+               With glibc-2.28, compilation fails and reports the invalid
+               back reference.  */
+            re_set_syntax (RE_SYNTAX_POSIX_EGREP);
+            memset (&regex, 0, sizeof regex);
+            s = re_compile_pattern ("0|()0|\\1|0", 10, &regex);
+            if (!s)
+              result |= 64;
+            else
+              {
+                if (strcmp (s, "Invalid back reference"))
+                  result |= 64;
+                regfree (&regex);
+              }
+
+#if 0
+            /* It would be nice to reject hosts whose regoff_t values are too
+               narrow (including glibc on hosts with 64-bit ptrdiff_t and
+               32-bit int), but we should wait until glibc implements this
+               feature.  Otherwise, support for equivalence classes and
+               multibyte collation symbols would always be broken except
+               when compiling --without-included-regex.   */
+            if (sizeof (regoff_t) < sizeof (ptrdiff_t)
+                || sizeof (regoff_t) < sizeof (ssize_t))
+              result |= 64;
+#endif
+
+            return result;
+          ]])],
+        [gl_cv_func_re_compile_pattern_working=yes],
+        [gl_cv_func_re_compile_pattern_working=no],
+        [case "$host_os" in
+                   # Guess no on native Windows.
+           mingw*) gl_cv_func_re_compile_pattern_working="guessing no" ;;
+                   # Otherwise obey --enable-cross-guesses.
+           *)      gl_cv_func_re_compile_pattern_working="$gl_cross_guess_normal" ;;
+         esac
+        ])
+      ])
+    case "$gl_cv_func_re_compile_pattern_working" in #(
+      *yes) ac_use_included_regex=no;; #(
+      *no) ac_use_included_regex=yes;;
+    esac
+    ;;
+  *) AC_MSG_ERROR([Invalid value for --with-included-regex: $with_included_regex])
+    ;;
+  esac
+
+  if test $ac_use_included_regex = yes; then
+    AC_DEFINE([_REGEX_INCLUDE_LIMITS_H], [1],
+      [Define if you want <regex.h> to include <limits.h>, so that it
+       consistently overrides <limits.h>'s RE_DUP_MAX.])
+    AC_DEFINE([_REGEX_LARGE_OFFSETS], [1],
+      [Define if you want regoff_t to be at least as wide POSIX requires.])
+    AC_DEFINE([re_syntax_options], [rpl_re_syntax_options],
+      [Define to rpl_re_syntax_options if the replacement should be used.])
+    AC_DEFINE([re_set_syntax], [rpl_re_set_syntax],
+      [Define to rpl_re_set_syntax if the replacement should be used.])
+    AC_DEFINE([re_compile_pattern], [rpl_re_compile_pattern],
+      [Define to rpl_re_compile_pattern if the replacement should be used.])
+    AC_DEFINE([re_compile_fastmap], [rpl_re_compile_fastmap],
+      [Define to rpl_re_compile_fastmap if the replacement should be used.])
+    AC_DEFINE([re_search], [rpl_re_search],
+      [Define to rpl_re_search if the replacement should be used.])
+    AC_DEFINE([re_search_2], [rpl_re_search_2],
+      [Define to rpl_re_search_2 if the replacement should be used.])
+    AC_DEFINE([re_match], [rpl_re_match],
+      [Define to rpl_re_match if the replacement should be used.])
+    AC_DEFINE([re_match_2], [rpl_re_match_2],
+      [Define to rpl_re_match_2 if the replacement should be used.])
+    AC_DEFINE([re_set_registers], [rpl_re_set_registers],
+      [Define to rpl_re_set_registers if the replacement should be used.])
+    AC_DEFINE([re_comp], [rpl_re_comp],
+      [Define to rpl_re_comp if the replacement should be used.])
+    AC_DEFINE([re_exec], [rpl_re_exec],
+      [Define to rpl_re_exec if the replacement should be used.])
+    AC_DEFINE([regcomp], [rpl_regcomp],
+      [Define to rpl_regcomp if the replacement should be used.])
+    AC_DEFINE([regexec], [rpl_regexec],
+      [Define to rpl_regexec if the replacement should be used.])
+    AC_DEFINE([regerror], [rpl_regerror],
+      [Define to rpl_regerror if the replacement should be used.])
+    AC_DEFINE([regfree], [rpl_regfree],
+      [Define to rpl_regfree if the replacement should be used.])
+  fi
+])
+
+# Prerequisites of lib/regex.c and lib/regex_internal.c.
+AC_DEFUN([gl_PREREQ_REGEX],
+[
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
+  AC_REQUIRE([AC_C_INLINE])
+  AC_REQUIRE([AC_C_RESTRICT])
+  AC_REQUIRE([AC_TYPE_MBSTATE_T])
+  AC_REQUIRE([gl_EEMALLOC])
+  AC_CHECK_HEADERS([libintl.h])
+  AC_CHECK_FUNCS_ONCE([isblank iswctype])
+  AC_CHECK_DECLS([isblank], [], [], [[#include <ctype.h>]])
+])
diff --git a/m4/rewinddir.m4 b/m4/rewinddir.m4
new file mode 100644
index 0000000..51f476b
--- /dev/null
+++ b/m4/rewinddir.m4
@@ -0,0 +1,15 @@
+# rewinddir.m4 serial 1
+dnl Copyright (C) 2011-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_REWINDDIR],
+[
+  AC_REQUIRE([gl_DIRENT_H_DEFAULTS])
+
+  AC_CHECK_FUNCS([rewinddir])
+  if test $ac_cv_func_rewinddir = no; then
+    HAVE_REWINDDIR=0
+  fi
+])
diff --git a/m4/save-cwd.m4 b/m4/save-cwd.m4
new file mode 100644
index 0000000..a401b1f
--- /dev/null
+++ b/m4/save-cwd.m4
@@ -0,0 +1,11 @@
+# serial 10
+dnl Copyright (C) 2002-2006, 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl Prerequisites for lib/save-cwd.c.
+AC_DEFUN([gl_SAVE_CWD],
+[
+  AC_CHECK_FUNCS_ONCE([fchdir])
+])
diff --git a/m4/sched_h.m4 b/m4/sched_h.m4
new file mode 100644
index 0000000..af0c43d
--- /dev/null
+++ b/m4/sched_h.m4
@@ -0,0 +1,91 @@
+# sched_h.m4 serial 12
+dnl Copyright (C) 2008-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl Written by Bruno Haible.
+
+AC_DEFUN([gl_SCHED_H],
+[
+  dnl Use AC_REQUIRE here, so that the default behavior below is expanded
+  dnl once only, before all statements that occur in other macros.
+  AC_REQUIRE([gl_SCHED_H_DEFAULTS])
+
+  AC_REQUIRE([AC_CANONICAL_HOST])
+
+  AC_CHECK_HEADERS_ONCE([sys/cdefs.h])
+  AC_CHECK_HEADERS([sched.h], [], [],
+    [[#if HAVE_SYS_CDEFS_H
+       #include <sys/cdefs.h>
+      #endif
+    ]])
+  gl_NEXT_HEADERS([sched.h])
+
+  if test "$ac_cv_header_sched_h" = yes; then
+    HAVE_SCHED_H=1
+  else
+    HAVE_SCHED_H=0
+  fi
+  AC_SUBST([HAVE_SCHED_H])
+
+  if test "$HAVE_SCHED_H" = 1; then
+    AC_CHECK_TYPE([struct sched_param],
+      [HAVE_STRUCT_SCHED_PARAM=1], [HAVE_STRUCT_SCHED_PARAM=0],
+      [[#if HAVE_SYS_CDEFS_H
+         #include <sys/cdefs.h>
+        #endif
+        #include <sched.h>
+      ]])
+  else
+    HAVE_STRUCT_SCHED_PARAM=0
+    case "$host_os" in
+      os2*)
+        dnl On OS/2 kLIBC, struct sched_param is in spawn.h.
+        AC_CHECK_TYPE([struct sched_param],
+          [HAVE_STRUCT_SCHED_PARAM=1], [],
+          [#include <spawn.h>])
+        ;;
+      vms)
+        dnl On OpenVMS 7.2 or newer, struct sched_param is in pthread.h.
+        AC_CHECK_TYPE([struct sched_param],
+          [HAVE_STRUCT_SCHED_PARAM=1], [],
+          [#include <pthread.h>])
+        ;;
+    esac
+  fi
+  AC_SUBST([HAVE_STRUCT_SCHED_PARAM])
+
+  if test "$ac_cv_header_sys_cdefs_h" = yes; then
+    HAVE_SYS_CDEFS_H=1
+  else
+    HAVE_SYS_CDEFS_H=0
+  fi
+  AC_SUBST([HAVE_SYS_CDEFS_H])
+
+  dnl Ensure the type pid_t gets defined.
+  AC_REQUIRE([AC_TYPE_PID_T])
+
+  dnl Check for declarations of anything we want to poison if the
+  dnl corresponding gnulib module is not in use, if it is not common
+  dnl enough to be declared everywhere.
+  gl_WARN_ON_USE_PREPARE([[#include <sched.h>
+    ]], [sched_yield])
+])
+
+AC_DEFUN([gl_SCHED_MODULE_INDICATOR],
+[
+  dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
+  AC_REQUIRE([gl_SCHED_H_DEFAULTS])
+  gl_MODULE_INDICATOR_SET_VARIABLE([$1])
+  dnl Define it also as a C macro, for the benefit of the unit tests.
+  gl_MODULE_INDICATOR_FOR_TESTS([$1])
+])
+
+AC_DEFUN([gl_SCHED_H_DEFAULTS],
+[
+  GNULIB_SCHED_YIELD=0;  AC_SUBST([GNULIB_SCHED_YIELD])
+  dnl Assume proper GNU behavior unless another module says otherwise.
+  HAVE_SCHED_YIELD=1;    AC_SUBST([HAVE_SCHED_YIELD])
+  REPLACE_SCHED_YIELD=0; AC_SUBST([REPLACE_SCHED_YIELD])
+])
diff --git a/m4/secure_getenv.m4 b/m4/secure_getenv.m4
new file mode 100644
index 0000000..29e2f53
--- /dev/null
+++ b/m4/secure_getenv.m4
@@ -0,0 +1,26 @@
+# Look up an environment variable more securely.
+dnl Copyright 2013-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_SECURE_GETENV],
+[
+  dnl Persuade glibc <stdlib.h> to declare secure_getenv().
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
+
+  AC_REQUIRE([gl_STDLIB_H_DEFAULTS])
+  AC_CHECK_FUNCS_ONCE([secure_getenv])
+  if test $ac_cv_func_secure_getenv = no; then
+    HAVE_SECURE_GETENV=0
+  fi
+])
+
+# Prerequisites of lib/secure_getenv.c.
+AC_DEFUN([gl_PREREQ_SECURE_GETENV], [
+  AC_CHECK_FUNCS([__secure_getenv])
+  if test $ac_cv_func___secure_getenv = no; then
+    AC_CHECK_FUNCS([issetugid])
+  fi
+  AC_CHECK_FUNCS_ONCE([getuid geteuid getgid getegid])
+])
diff --git a/m4/select.m4 b/m4/select.m4
new file mode 100644
index 0000000..90d2bb9
--- /dev/null
+++ b/m4/select.m4
@@ -0,0 +1,117 @@
+# select.m4 serial 12
+dnl Copyright (C) 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_SELECT],
+[
+  AC_REQUIRE([gl_HEADER_SYS_SELECT])
+  AC_REQUIRE([AC_C_RESTRICT])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_REQUIRE([gl_SOCKETS])
+  if test "$ac_cv_header_winsock2_h" = yes; then
+    REPLACE_SELECT=1
+  else
+    dnl On Interix 3.5, select(0, NULL, NULL, NULL, timeout) fails with error
+    dnl EFAULT.
+    AC_CHECK_HEADERS_ONCE([sys/select.h])
+    AC_CACHE_CHECK([whether select supports a 0 argument],
+      [gl_cv_func_select_supports0],
+      [
+        AC_RUN_IFELSE([AC_LANG_SOURCE([[
+#include <sys/types.h>
+#include <sys/time.h>
+#if HAVE_SYS_SELECT_H
+#include <sys/select.h>
+#endif
+int main ()
+{
+  struct timeval timeout;
+  timeout.tv_sec = 0;
+  timeout.tv_usec = 5;
+  return select (0, (fd_set *)0, (fd_set *)0, (fd_set *)0, &timeout) < 0;
+}]])], [gl_cv_func_select_supports0=yes], [gl_cv_func_select_supports0=no],
+          [
+changequote(,)dnl
+           case "$host_os" in
+                       # Guess no on Interix.
+             interix*) gl_cv_func_select_supports0="guessing no";;
+                       # Guess yes otherwise.
+             *)        gl_cv_func_select_supports0="guessing yes";;
+           esac
+changequote([,])dnl
+          ])
+      ])
+    case "$gl_cv_func_select_supports0" in
+      *yes) ;;
+      *) REPLACE_SELECT=1 ;;
+    esac
+
+    dnl On FreeBSD 8.2, select() doesn't always reject bad fds.
+    AC_CACHE_CHECK([whether select detects invalid fds],
+      [gl_cv_func_select_detects_ebadf],
+      [
+        AC_RUN_IFELSE([AC_LANG_PROGRAM([[
+#include <sys/types.h>
+#include <sys/time.h>
+#if HAVE_SYS_SELECT_H
+# include <sys/select.h>
+#endif
+#include <unistd.h>
+#include <errno.h>
+]GL_MDA_DEFINES],
+[[
+  fd_set set;
+  dup2(0, 16);
+  FD_ZERO(&set);
+  FD_SET(16, &set);
+  close(16);
+  struct timeval timeout;
+  timeout.tv_sec = 0;
+  timeout.tv_usec = 5;
+  return select (17, &set, NULL, NULL, &timeout) != -1 || errno != EBADF;
+]])], [gl_cv_func_select_detects_ebadf=yes],
+      [gl_cv_func_select_detects_ebadf=no],
+          [
+           case "$host_os" in
+                             # Guess yes on Linux systems.
+            linux-* | linux) gl_cv_func_select_detects_ebadf="guessing yes" ;;
+                             # Guess yes on glibc systems.
+            *-gnu* | gnu*)   gl_cv_func_select_detects_ebadf="guessing yes" ;;
+                             # If we don't know, obey --enable-cross-guesses.
+            *)               gl_cv_func_select_detects_ebadf="$gl_cross_guess_normal" ;;
+           esac
+          ])
+      ])
+    case $gl_cv_func_select_detects_ebadf in
+      *yes) ;;
+      *) REPLACE_SELECT=1 ;;
+    esac
+  fi
+
+  dnl Determine the needed libraries.
+  LIB_SELECT="$LIBSOCKET"
+  if test $REPLACE_SELECT = 1; then
+    case "$host_os" in
+      mingw*)
+        dnl On the MSVC platform, the function MsgWaitForMultipleObjects
+        dnl (used in lib/select.c) requires linking with -luser32. On mingw,
+        dnl it is implicit.
+        AC_LINK_IFELSE(
+          [AC_LANG_SOURCE([[
+#define WIN32_LEAN_AND_MEAN
+#include <windows.h>
+int
+main ()
+{
+  MsgWaitForMultipleObjects (0, NULL, 0, 0, 0);
+  return 0;
+}]])],
+          [],
+          [LIB_SELECT="$LIB_SELECT -luser32"])
+        ;;
+    esac
+  fi
+  AC_SUBST([LIB_SELECT])
+])
diff --git a/m4/servent.m4 b/m4/servent.m4
new file mode 100644
index 0000000..2041c7e
--- /dev/null
+++ b/m4/servent.m4
@@ -0,0 +1,51 @@
+# servent.m4 serial 3
+dnl Copyright (C) 2008, 2010-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_SERVENT],
+[
+  dnl Where are getservent(), setservent(), endservent(), getservbyname(),
+  dnl getservbyport() defined?
+  dnl Where are getprotoent(), setprotoent(), endprotoent(), getprotobyname(),
+  dnl getprotobynumber() defined?
+  dnl - On Solaris < 11.4, they are in libsocket. Ignore libxnet.
+  dnl - On Haiku, they are in libnetwork.
+  dnl - On BeOS, they are in libnet.
+  dnl - On native Windows, they are in ws2_32.dll.
+  dnl - Otherwise they are in libc.
+  AC_REQUIRE([gl_HEADER_SYS_SOCKET])dnl for HAVE_SYS_SOCKET_H, HAVE_WINSOCK2_H
+  SERVENT_LIB=
+  gl_saved_libs="$LIBS"
+  AC_SEARCH_LIBS([getservbyname], [socket network net],
+    [if test "$ac_cv_search_getservbyname" != "none required"; then
+       SERVENT_LIB="$ac_cv_search_getservbyname"
+     fi])
+  LIBS="$gl_saved_libs"
+  if test -z "$SERVENT_LIB"; then
+    AC_CHECK_FUNCS([getservbyname], , [
+      AC_CACHE_CHECK([for getservbyname in winsock2.h and -lws2_32],
+        [gl_cv_w32_getservbyname],
+        [gl_cv_w32_getservbyname=no
+         gl_save_LIBS="$LIBS"
+         LIBS="$LIBS -lws2_32"
+         AC_LINK_IFELSE(
+           [AC_LANG_PROGRAM(
+              [[
+#ifdef HAVE_WINSOCK2_H
+#include <winsock2.h>
+#endif
+#include <stddef.h>
+              ]],
+              [[getservbyname(NULL,NULL);]])],
+           [gl_cv_w32_getservbyname=yes])
+         LIBS="$gl_save_LIBS"
+        ])
+      if test "$gl_cv_w32_getservbyname" = "yes"; then
+        SERVENT_LIB="-lws2_32"
+      fi
+    ])
+  fi
+  AC_SUBST([SERVENT_LIB])
+])
diff --git a/m4/setlocale_null.m4 b/m4/setlocale_null.m4
new file mode 100644
index 0000000..fc1e3e1
--- /dev/null
+++ b/m4/setlocale_null.m4
@@ -0,0 +1,98 @@
+# setlocale_null.m4 serial 4
+dnl Copyright (C) 2019-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_SETLOCALE_NULL],
+[
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  AC_REQUIRE([gl_PTHREADLIB])
+  AC_CHECK_HEADERS_ONCE([threads.h])
+
+  AC_CACHE_CHECK([whether setlocale (LC_ALL, NULL) is multithread-safe],
+    [gl_cv_func_setlocale_null_all_mtsafe],
+    [case "$host_os" in
+       # Guess no on musl libc, macOS, FreeBSD, NetBSD, OpenBSD, AIX, Haiku, Cygwin.
+       *-musl* | darwin* | freebsd* | netbsd* | openbsd* | aix* | haiku* | cygwin*)
+         gl_cv_func_setlocale_null_all_mtsafe=no ;;
+       # Guess yes on glibc, HP-UX, IRIX, Solaris, native Windows.
+       *-gnu* | gnu* | hpux* | irix* | solaris* | mingw*)
+         gl_cv_func_setlocale_null_all_mtsafe=yes ;;
+       # If we don't know, obey --enable-cross-guesses.
+       *)
+         gl_cv_func_setlocale_null_all_mtsafe="$gl_cross_guess_normal" ;;
+     esac
+    ])
+  dnl On platforms without multithreading, there is no issue.
+  case "$host_os" in
+    mingw*) ;;
+    *)
+      if test $gl_pthread_api = no && test $ac_cv_header_threads_h = no; then
+        gl_cv_func_setlocale_null_all_mtsafe="trivially yes"
+      fi
+      ;;
+  esac
+  case "$gl_cv_func_setlocale_null_all_mtsafe" in
+    *yes) SETLOCALE_NULL_ALL_MTSAFE=1 ;;
+    *)    SETLOCALE_NULL_ALL_MTSAFE=0 ;;
+  esac
+  AC_DEFINE_UNQUOTED([SETLOCALE_NULL_ALL_MTSAFE], [$SETLOCALE_NULL_ALL_MTSAFE],
+    [Define to 1 if setlocale (LC_ALL, NULL) is multithread-safe.])
+
+  dnl This is about a single category (not LC_ALL).
+  AC_CACHE_CHECK([whether setlocale (category, NULL) is multithread-safe],
+    [gl_cv_func_setlocale_null_one_mtsafe],
+    [case "$host_os" in
+       # Guess no on OpenBSD, AIX.
+       openbsd* | aix*)
+         gl_cv_func_setlocale_null_one_mtsafe=no ;;
+       # Guess yes on glibc, musl libc, macOS, FreeBSD, NetBSD, HP-UX, IRIX, Solaris, Haiku, Cygwin, native Windows.
+       *-gnu* | gnu* | *-musl* | darwin* | freebsd* | netbsd* | hpux* | irix* | solaris* | haiku* | cygwin* | mingw*)
+         gl_cv_func_setlocale_null_one_mtsafe=yes ;;
+       # If we don't know, obey --enable-cross-guesses.
+       *)
+         gl_cv_func_setlocale_null_one_mtsafe="$gl_cross_guess_normal" ;;
+     esac
+    ])
+  dnl On platforms without multithreading, there is no issue.
+  case "$host_os" in
+    mingw*) ;;
+    *)
+      if test $gl_pthread_api = no && test $ac_cv_header_threads_h = no; then
+        gl_cv_func_setlocale_null_one_mtsafe="trivially yes"
+      fi
+      ;;
+  esac
+  case "$gl_cv_func_setlocale_null_one_mtsafe" in
+    *yes) SETLOCALE_NULL_ONE_MTSAFE=1 ;;
+    *)    SETLOCALE_NULL_ONE_MTSAFE=0 ;;
+  esac
+  AC_DEFINE_UNQUOTED([SETLOCALE_NULL_ONE_MTSAFE], [$SETLOCALE_NULL_ONE_MTSAFE],
+    [Define to 1 if setlocale (category, NULL) is multithread-safe.])
+
+  dnl Determine link dependencies of lib/setlocale_null.c and lib/setlocale-lock.c.
+  if test $SETLOCALE_NULL_ALL_MTSAFE = 0 || test $SETLOCALE_NULL_ONE_MTSAFE = 0; then
+    case "$host_os" in
+      mingw*) LIB_SETLOCALE_NULL= ;;
+      *)
+        gl_WEAK_SYMBOLS
+        case "$gl_cv_have_weak" in
+          *yes) LIB_SETLOCALE_NULL= ;;
+          *)    LIB_SETLOCALE_NULL="$LIBPTHREAD" ;;
+        esac
+        ;;
+    esac
+  else
+    LIB_SETLOCALE_NULL=
+  fi
+  dnl LIB_SETLOCALE_NULL is expected to be '-pthread' or '-lpthread' on AIX
+  dnl with gcc or xlc, and empty otherwise.
+  AC_SUBST([LIB_SETLOCALE_NULL])
+])
+
+# Prerequisites of lib/setlocale-lock.c.
+AC_DEFUN([gl_PREREQ_SETLOCALE_LOCK],
+[
+  gl_VISIBILITY
+])
diff --git a/m4/sh-filename.m4 b/m4/sh-filename.m4
new file mode 100644
index 0000000..63bbd67
--- /dev/null
+++ b/m4/sh-filename.m4
@@ -0,0 +1,24 @@
+# sh-filename.m4 serial 3
+dnl Copyright (C) 2018-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl From Bruno Haible.
+
+AC_DEFUN([gl_SH_FILENAME],
+[
+  AH_VERBATIM([SH_FILENAME],
+[/* File name of the Bourne shell.  */
+#if (defined _WIN32 && !defined __CYGWIN__) || defined __CYGWIN__ || defined __ANDROID__
+/* Omit the directory part because
+   - For native Windows programs in a Cygwin environment, the Cygwin mounts
+     are not visible.
+   - For 32-bit Cygwin programs in a 64-bit Cygwin environment, the Cygwin
+     mounts are not visible.
+   - On Android, /bin/sh does not exist. It's /system/bin/sh instead.  */
+# define BOURNE_SHELL "sh"
+#else
+# define BOURNE_SHELL "/bin/sh"
+#endif])
+])
diff --git a/m4/sha1.m4 b/m4/sha1.m4
new file mode 100644
index 0000000..35e3f75
--- /dev/null
+++ b/m4/sha1.m4
@@ -0,0 +1,14 @@
+# sha1.m4 serial 12
+dnl Copyright (C) 2002-2006, 2008-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_SHA1],
+[
+  dnl Prerequisites of lib/sha1.c.
+  AC_REQUIRE([gl_BIGENDIAN])
+
+  dnl Determine HAVE_OPENSSL_SHA1 and LIB_CRYPTO
+  gl_CRYPTO_CHECK([SHA1])
+])
diff --git a/m4/sha256.m4 b/m4/sha256.m4
new file mode 100644
index 0000000..85ff1d5
--- /dev/null
+++ b/m4/sha256.m4
@@ -0,0 +1,14 @@
+# sha256.m4 serial 8
+dnl Copyright (C) 2005, 2008-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_SHA256],
+[
+  dnl Prerequisites of lib/sha256.c.
+  AC_REQUIRE([gl_BIGENDIAN])
+
+  dnl Determine HAVE_OPENSSL_SHA256 and LIB_CRYPTO
+  gl_CRYPTO_CHECK([SHA256])
+])
diff --git a/m4/sha512.m4 b/m4/sha512.m4
new file mode 100644
index 0000000..fe1592a
--- /dev/null
+++ b/m4/sha512.m4
@@ -0,0 +1,14 @@
+# sha512.m4 serial 9
+dnl Copyright (C) 2005-2006, 2008-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_SHA512],
+[
+  dnl Prerequisites of lib/sha512.c.
+  AC_REQUIRE([gl_BIGENDIAN])
+
+  dnl Determine HAVE_OPENSSL_SHA512 and LIB_CRYPTO
+  gl_CRYPTO_CHECK([SHA512])
+])
diff --git a/m4/sig_atomic_t.m4 b/m4/sig_atomic_t.m4
new file mode 100644
index 0000000..d695caa
--- /dev/null
+++ b/m4/sig_atomic_t.m4
@@ -0,0 +1,14 @@
+# sig_atomic_t.m4 serial 3
+dnl Copyright (C) 2003, 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gt_TYPE_SIG_ATOMIC_T],
+[
+  AC_CHECK_TYPES([sig_atomic_t], ,
+    [AC_DEFINE([sig_atomic_t], [int],
+       [Define as an integer type suitable for memory locations that can be
+        accessed atomically even in the presence of asynchronous signals.])],
+    [#include <signal.h>])
+])
diff --git a/m4/sigaction.m4 b/m4/sigaction.m4
new file mode 100644
index 0000000..9a2d201
--- /dev/null
+++ b/m4/sigaction.m4
@@ -0,0 +1,40 @@
+# sigaction.m4 serial 7
+dnl Copyright (C) 2008-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+# Determine if sigaction interface is present.
+AC_DEFUN([gl_SIGACTION],
+[
+  AC_REQUIRE([gl_SIGNAL_H_DEFAULTS])
+  AC_CHECK_FUNCS_ONCE([sigaction])
+  if test $ac_cv_func_sigaction = yes; then
+    AC_CHECK_MEMBERS([struct sigaction.sa_sigaction], , ,
+                     [[#include <signal.h>]])
+    if test $ac_cv_member_struct_sigaction_sa_sigaction = no; then
+      HAVE_STRUCT_SIGACTION_SA_SIGACTION=0
+    fi
+  else
+    HAVE_SIGACTION=0
+  fi
+])
+
+# Prerequisites of the part of lib/signal.in.h and of lib/sigaction.c.
+AC_DEFUN([gl_PREREQ_SIGACTION],
+[
+  AC_REQUIRE([gl_SIGNAL_H_DEFAULTS])
+  AC_REQUIRE([AC_C_RESTRICT])
+  AC_REQUIRE([AC_TYPE_UID_T])
+  AC_REQUIRE([gl_PREREQ_SIG_HANDLER_H])
+  AC_CHECK_FUNCS_ONCE([sigaltstack siginterrupt])
+  AC_CHECK_TYPES([siginfo_t], [], [], [[
+#include <signal.h>
+  ]])
+  if test $ac_cv_type_siginfo_t = no; then
+    HAVE_SIGINFO_T=0
+  fi
+])
+
+# Prerequisites of lib/sig-handler.h.
+AC_DEFUN([gl_PREREQ_SIG_HANDLER_H], [:])
diff --git a/m4/signal_h.m4 b/m4/signal_h.m4
new file mode 100644
index 0000000..b262980
--- /dev/null
+++ b/m4/signal_h.m4
@@ -0,0 +1,85 @@
+# signal_h.m4 serial 19
+dnl Copyright (C) 2007-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_SIGNAL_H],
+[
+  AC_REQUIRE([gl_SIGNAL_H_DEFAULTS])
+  AC_REQUIRE([gl_CHECK_TYPE_SIGSET_T])
+  gl_NEXT_HEADERS([signal.h])
+
+# AIX declares sig_atomic_t to already include volatile, and C89 compilers
+# then choke on 'volatile sig_atomic_t'.  C99 requires that it compile.
+  AC_CHECK_TYPE([volatile sig_atomic_t], [],
+    [HAVE_TYPE_VOLATILE_SIG_ATOMIC_T=0], [[
+#include <signal.h>
+    ]])
+
+  dnl Ensure the type pid_t gets defined.
+  AC_REQUIRE([AC_TYPE_PID_T])
+
+  AC_REQUIRE([AC_TYPE_UID_T])
+
+  dnl Persuade glibc <signal.h> to define sighandler_t.
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
+  AC_CHECK_TYPE([sighandler_t], [], [HAVE_SIGHANDLER_T=0], [[
+#include <signal.h>
+    ]])
+
+  dnl Check for declarations of anything we want to poison if the
+  dnl corresponding gnulib module is not in use.
+  gl_WARN_ON_USE_PREPARE([[#include <signal.h>
+    ]], [pthread_sigmask sigaction
+    sigaddset sigdelset sigemptyset sigfillset sigismember
+    sigpending sigprocmask])
+
+  AC_REQUIRE([AC_C_RESTRICT])
+])
+
+AC_DEFUN([gl_CHECK_TYPE_SIGSET_T],
+[
+  AC_CHECK_TYPES([sigset_t],
+    [gl_cv_type_sigset_t=yes], [gl_cv_type_sigset_t=no],
+    [[
+      #include <signal.h>
+      /* Mingw defines sigset_t not in <signal.h>, but in <sys/types.h>.  */
+      #include <sys/types.h>
+    ]])
+  if test $gl_cv_type_sigset_t != yes; then
+    HAVE_SIGSET_T=0
+  fi
+])
+
+AC_DEFUN([gl_SIGNAL_MODULE_INDICATOR],
+[
+  dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
+  AC_REQUIRE([gl_SIGNAL_H_DEFAULTS])
+  gl_MODULE_INDICATOR_SET_VARIABLE([$1])
+  dnl Define it also as a C macro, for the benefit of the unit tests.
+  gl_MODULE_INDICATOR_FOR_TESTS([$1])
+])
+
+AC_DEFUN([gl_SIGNAL_H_DEFAULTS],
+[
+  GNULIB_PTHREAD_SIGMASK=0;    AC_SUBST([GNULIB_PTHREAD_SIGMASK])
+  GNULIB_RAISE=0;              AC_SUBST([GNULIB_RAISE])
+  GNULIB_SIGNAL_H_SIGPIPE=0;   AC_SUBST([GNULIB_SIGNAL_H_SIGPIPE])
+  GNULIB_SIGPROCMASK=0;        AC_SUBST([GNULIB_SIGPROCMASK])
+  GNULIB_SIGACTION=0;          AC_SUBST([GNULIB_SIGACTION])
+  dnl Assume proper GNU behavior unless another module says otherwise.
+  HAVE_POSIX_SIGNALBLOCKING=1; AC_SUBST([HAVE_POSIX_SIGNALBLOCKING])
+  HAVE_PTHREAD_SIGMASK=1;      AC_SUBST([HAVE_PTHREAD_SIGMASK])
+  HAVE_RAISE=1;                AC_SUBST([HAVE_RAISE])
+  HAVE_SIGSET_T=1;             AC_SUBST([HAVE_SIGSET_T])
+  HAVE_SIGINFO_T=1;            AC_SUBST([HAVE_SIGINFO_T])
+  HAVE_SIGACTION=1;            AC_SUBST([HAVE_SIGACTION])
+  HAVE_STRUCT_SIGACTION_SA_SIGACTION=1;
+                               AC_SUBST([HAVE_STRUCT_SIGACTION_SA_SIGACTION])
+  HAVE_TYPE_VOLATILE_SIG_ATOMIC_T=1;
+                               AC_SUBST([HAVE_TYPE_VOLATILE_SIG_ATOMIC_T])
+  HAVE_SIGHANDLER_T=1;         AC_SUBST([HAVE_SIGHANDLER_T])
+  REPLACE_PTHREAD_SIGMASK=0;   AC_SUBST([REPLACE_PTHREAD_SIGMASK])
+  REPLACE_RAISE=0;             AC_SUBST([REPLACE_RAISE])
+])
diff --git a/m4/signalblocking.m4 b/m4/signalblocking.m4
new file mode 100644
index 0000000..b7cff8d
--- /dev/null
+++ b/m4/signalblocking.m4
@@ -0,0 +1,23 @@
+# signalblocking.m4 serial 17
+dnl Copyright (C) 2001-2002, 2006-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+# Determine available signal blocking primitives. Three different APIs exist:
+# 1) POSIX: sigemptyset, sigaddset, sigprocmask
+# 2) SYSV: sighold, sigrelse
+# 3) BSD: sigblock, sigsetmask
+# For simplicity, here we check only for the POSIX signal blocking.
+AC_DEFUN([gl_SIGNALBLOCKING],
+[
+  AC_REQUIRE([gl_SIGNAL_H_DEFAULTS])
+  AC_REQUIRE([gl_CHECK_TYPE_SIGSET_T])
+  HAVE_POSIX_SIGNALBLOCKING=0
+  if test "$gl_cv_type_sigset_t" = yes; then
+    AC_CHECK_FUNC([sigprocmask], [HAVE_POSIX_SIGNALBLOCKING=1])
+  fi
+])
+
+# Prerequisites of lib/sigprocmask.c.
+AC_DEFUN([gl_PREREQ_SIGPROCMASK], [:])
diff --git a/m4/sigpipe.m4 b/m4/sigpipe.m4
new file mode 100644
index 0000000..dfbf4e0
--- /dev/null
+++ b/m4/sigpipe.m4
@@ -0,0 +1,29 @@
+# sigpipe.m4 serial 2
+dnl Copyright (C) 2008-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl Tests whether SIGPIPE is provided by <signal.h>.
+dnl Sets gl_cv_header_signal_h_SIGPIPE.
+AC_DEFUN([gl_SIGNAL_SIGPIPE],
+[
+  dnl Use AC_REQUIRE here, so that the default behavior below is expanded
+  dnl once only, before all statements that occur in other macros.
+  AC_REQUIRE([gl_SIGNAL_SIGPIPE_BODY])
+])
+
+AC_DEFUN([gl_SIGNAL_SIGPIPE_BODY],
+[
+  AC_REQUIRE([AC_PROG_CC])
+  AC_CACHE_CHECK([for SIGPIPE], [gl_cv_header_signal_h_SIGPIPE], [
+    AC_EGREP_CPP([booboo],[
+#include <signal.h>
+#if !defined SIGPIPE
+booboo
+#endif
+      ],
+      [gl_cv_header_signal_h_SIGPIPE=no],
+      [gl_cv_header_signal_h_SIGPIPE=yes])
+  ])
+])
diff --git a/m4/size_max.m4 b/m4/size_max.m4
new file mode 100644
index 0000000..6ebb93f
--- /dev/null
+++ b/m4/size_max.m4
@@ -0,0 +1,75 @@
+# size_max.m4 serial 12
+dnl Copyright (C) 2003, 2005-2006, 2008-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl From Bruno Haible.
+
+AC_PREREQ([2.61])
+
+AC_DEFUN([gl_SIZE_MAX],
+[
+  AC_CHECK_HEADERS([stdint.h])
+  dnl First test whether the system already has SIZE_MAX.
+  AC_CACHE_CHECK([for SIZE_MAX], [gl_cv_size_max], [
+    gl_cv_size_max=no
+    AC_EGREP_CPP([Found it], [
+#include <limits.h>
+#if HAVE_STDINT_H
+#include <stdint.h>
+#endif
+#ifdef SIZE_MAX
+Found it
+#endif
+], [gl_cv_size_max=yes])
+    if test $gl_cv_size_max != yes; then
+      dnl Define it ourselves. Here we assume that the type 'size_t' is not wider
+      dnl than the type 'unsigned long'. Try hard to find a definition that can
+      dnl be used in a preprocessor #if, i.e. doesn't contain a cast.
+      AC_COMPUTE_INT([size_t_bits_minus_1], [sizeof (size_t) * CHAR_BIT - 1],
+        [#include <stddef.h>
+#include <limits.h>], [size_t_bits_minus_1=])
+      AC_COMPUTE_INT([fits_in_uint], [sizeof (size_t) <= sizeof (unsigned int)],
+        [#include <stddef.h>], [fits_in_uint=])
+      if test -n "$size_t_bits_minus_1" && test -n "$fits_in_uint"; then
+        if test $fits_in_uint = 1; then
+          dnl Even though SIZE_MAX fits in an unsigned int, it must be of type
+          dnl 'unsigned long' if the type 'size_t' is the same as 'unsigned long'.
+          AC_COMPILE_IFELSE(
+            [AC_LANG_PROGRAM(
+               [[#include <stddef.h>
+                 extern size_t foo;
+                 extern unsigned long foo;
+               ]],
+               [[]])],
+            [fits_in_uint=0])
+        fi
+        dnl We cannot use 'expr' to simplify this expression, because 'expr'
+        dnl works only with 'long' integers in the host environment, while we
+        dnl might be cross-compiling from a 32-bit platform to a 64-bit platform.
+        if test $fits_in_uint = 1; then
+          gl_cv_size_max="(((1U << $size_t_bits_minus_1) - 1) * 2 + 1)"
+        else
+          gl_cv_size_max="(((1UL << $size_t_bits_minus_1) - 1) * 2 + 1)"
+        fi
+      else
+        dnl Shouldn't happen, but who knows...
+        gl_cv_size_max='((size_t)~(size_t)0)'
+      fi
+    fi
+  ])
+  if test "$gl_cv_size_max" != yes; then
+    AC_DEFINE_UNQUOTED([SIZE_MAX], [$gl_cv_size_max],
+      [Define as the maximum value of type 'size_t', if the system doesn't define it.])
+  fi
+  dnl Don't redefine SIZE_MAX in config.h if config.h is re-included after
+  dnl <stdint.h>. Remember that the #undef in AH_VERBATIM gets replaced with
+  dnl #define by AC_DEFINE_UNQUOTED.
+  AH_VERBATIM([SIZE_MAX],
+[/* Define as the maximum value of type 'size_t', if the system doesn't define
+   it. */
+#ifndef SIZE_MAX
+# undef SIZE_MAX
+#endif])
+])
diff --git a/m4/snprintf.m4 b/m4/snprintf.m4
new file mode 100644
index 0000000..126039d
--- /dev/null
+++ b/m4/snprintf.m4
@@ -0,0 +1,62 @@
+# snprintf.m4 serial 7
+dnl Copyright (C) 2002-2004, 2007-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl Libintl 0.17 will replace snprintf only if it does not support %1$s,
+dnl but defers to any gnulib snprintf replacements.  Therefore, gnulib
+dnl must guarantee that the decision for replacing snprintf is a superset
+dnl of the reasons checked by libintl.
+AC_DEFUN([gl_FUNC_SNPRINTF],
+[
+  AC_REQUIRE([gl_STDIO_H_DEFAULTS])
+  gl_cv_func_snprintf_usable=no
+  AC_CHECK_FUNCS([snprintf])
+  if test $ac_cv_func_snprintf = yes; then
+    gl_SNPRINTF_SIZE1
+    case "$gl_cv_func_snprintf_size1" in
+      *yes)
+        gl_SNPRINTF_RETVAL_C99
+        case "$gl_cv_func_snprintf_retval_c99" in
+          *yes)
+            gl_PRINTF_POSITIONS
+            case "$gl_cv_func_printf_positions" in
+              *yes)
+                gl_cv_func_snprintf_usable=yes
+                ;;
+            esac
+            ;;
+        esac
+        ;;
+    esac
+  fi
+  if test $gl_cv_func_snprintf_usable = no; then
+    gl_REPLACE_SNPRINTF
+  fi
+  AC_CHECK_DECLS_ONCE([snprintf])
+  if test $ac_cv_have_decl_snprintf = no; then
+    HAVE_DECL_SNPRINTF=0
+  fi
+])
+
+AC_DEFUN([gl_REPLACE_SNPRINTF],
+[
+  AC_REQUIRE([gl_STDIO_H_DEFAULTS])
+  AC_LIBOBJ([snprintf])
+  if test $ac_cv_func_snprintf = yes; then
+    REPLACE_SNPRINTF=1
+  else
+    AC_CHECK_DECLS_ONCE([snprintf])
+    if test $ac_cv_have_decl_snprintf = yes; then
+      dnl If the function is declared but does not appear to exist, it may be
+      dnl defined as an inline function. In order to avoid a conflict, we have
+      dnl to define rpl_snprintf, not snprintf.
+      REPLACE_SNPRINTF=1
+    fi
+  fi
+  gl_PREREQ_SNPRINTF
+])
+
+# Prerequisites of lib/snprintf.c.
+AC_DEFUN([gl_PREREQ_SNPRINTF], [:])
diff --git a/m4/socketlib.m4 b/m4/socketlib.m4
new file mode 100644
index 0000000..48dd7d6
--- /dev/null
+++ b/m4/socketlib.m4
@@ -0,0 +1,96 @@
+# socketlib.m4 serial 3
+dnl Copyright (C) 2008-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl gl_SOCKETLIB
+dnl Determines the library to use for socket functions.
+dnl Sets and AC_SUBSTs LIBSOCKET.
+
+AC_DEFUN([gl_SOCKETLIB],
+[
+  gl_PREREQ_SYS_H_WINSOCK2 dnl for HAVE_WINSOCK2_H
+  LIBSOCKET=
+  if test $HAVE_WINSOCK2_H = 1; then
+    dnl Native Windows API (not Cygwin).
+    dnl If the function WSAStartup exists (declared in <winsock2.h> and
+    dnl defined through -lws2_32), we need to call it.
+    AC_CACHE_CHECK([for WSAStartup],
+      [gl_cv_func_wsastartup], [
+       gl_save_LIBS="$LIBS"
+       LIBS="$LIBS -lws2_32"
+       AC_LINK_IFELSE(
+         [AC_LANG_PROGRAM([[
+#ifdef HAVE_WINSOCK2_H
+# include <winsock2.h>
+#endif]], [[
+            WORD wVersionRequested = MAKEWORD(1, 1);
+            WSADATA wsaData;
+            int err = WSAStartup(wVersionRequested, &wsaData);
+            WSACleanup ();
+            ]])
+         ],
+         [gl_cv_func_wsastartup=yes],
+         [gl_cv_func_wsastartup=no])
+       LIBS="$gl_save_LIBS"
+      ])
+    if test "$gl_cv_func_wsastartup" = "yes"; then
+      AC_DEFINE([WINDOWS_SOCKETS], [1], [Define if WSAStartup is needed.])
+      LIBSOCKET='-lws2_32'
+    fi
+  else
+    dnl Unix API.
+    dnl Solaris has most socket functions in libsocket.
+    dnl Haiku has most socket functions in libnetwork.
+    dnl BeOS has most socket functions in libnet.
+    dnl On HP-UX, do NOT link with libxnet, because in 64-bit mode this would
+    dnl break code (e.g. in libraries) that invokes accept(), getpeername(),
+    dnl getsockname(), getsockopt(), or recvfrom() with a 32-bit addrlen. See
+    dnl "man xopen_networking" for details.
+    AC_CACHE_CHECK([for library containing setsockopt], [gl_cv_lib_socket], [
+      gl_cv_lib_socket=
+      AC_LINK_IFELSE([AC_LANG_PROGRAM([[extern
+#ifdef __cplusplus
+"C"
+#endif
+char setsockopt();]], [[setsockopt();]])],
+        [],
+        [gl_save_LIBS="$LIBS"
+         LIBS="$gl_save_LIBS -lsocket"
+         AC_LINK_IFELSE([AC_LANG_PROGRAM([[extern
+#ifdef __cplusplus
+"C"
+#endif
+char setsockopt();]], [[setsockopt();]])],
+           [gl_cv_lib_socket="-lsocket"])
+         if test -z "$gl_cv_lib_socket"; then
+           LIBS="$gl_save_LIBS -lnetwork"
+           AC_LINK_IFELSE([AC_LANG_PROGRAM([[extern
+#ifdef __cplusplus
+"C"
+#endif
+char setsockopt();]], [[setsockopt();]])],
+             [gl_cv_lib_socket="-lnetwork"])
+           if test -z "$gl_cv_lib_socket"; then
+             LIBS="$gl_save_LIBS -lnet"
+             AC_LINK_IFELSE([AC_LANG_PROGRAM([[extern
+#ifdef __cplusplus
+"C"
+#endif
+char setsockopt();]], [[setsockopt();]])],
+               [gl_cv_lib_socket="-lnet"])
+           fi
+         fi
+         LIBS="$gl_save_LIBS"
+        ])
+      if test -z "$gl_cv_lib_socket"; then
+        gl_cv_lib_socket="none needed"
+      fi
+    ])
+    if test "$gl_cv_lib_socket" != "none needed"; then
+      LIBSOCKET="$gl_cv_lib_socket"
+    fi
+  fi
+  AC_SUBST([LIBSOCKET])
+])
diff --git a/m4/sockets.m4 b/m4/sockets.m4
new file mode 100644
index 0000000..7e53ef2
--- /dev/null
+++ b/m4/sockets.m4
@@ -0,0 +1,17 @@
+# sockets.m4 serial 7
+dnl Copyright (C) 2008-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_SOCKETS],
+[
+  AC_REQUIRE([AC_C_INLINE])
+  AC_REQUIRE([gl_SOCKETLIB])
+  gl_PREREQ_SOCKETS
+])
+
+# Prerequisites of lib/sockets.c.
+AC_DEFUN([gl_PREREQ_SOCKETS], [
+  :
+])
diff --git a/m4/socklen.m4 b/m4/socklen.m4
new file mode 100644
index 0000000..251960b
--- /dev/null
+++ b/m4/socklen.m4
@@ -0,0 +1,76 @@
+# socklen.m4 serial 11
+dnl Copyright (C) 2005-2007, 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl From Albert Chin, Windows fixes from Simon Josefsson.
+
+dnl Check for socklen_t: historically on BSD it is an int, and in
+dnl POSIX 1g it is a type of its own, but some platforms use different
+dnl types for the argument to getsockopt, getpeername, etc.:
+dnl HP-UX 10.20, IRIX 6.5, OSF/1 4.0, Interix 3.5, BeOS.
+dnl So we have to test to find something that will work.
+
+AC_DEFUN([gl_TYPE_SOCKLEN_T],
+  [AC_REQUIRE([gl_CHECK_SOCKET_HEADERS])dnl
+   AC_CHECK_TYPE([socklen_t], ,
+     [AC_CACHE_CHECK([for socklen_t equivalent],
+        [gl_cv_socklen_t_equiv],
+        [# Systems have either "struct sockaddr *" or
+         # "void *" as the second argument to getpeername
+         gl_cv_socklen_t_equiv=
+         for arg2 in "struct sockaddr" void; do
+           for t in int size_t "unsigned int" "long int" "unsigned long int"; do
+             AC_COMPILE_IFELSE([AC_LANG_PROGRAM(
+                 [[#include <sys/types.h>
+                   #include <sys/socket.h>
+
+                   int getpeername (int, $arg2 *, $t *);]],
+                 [[$t len;
+                  getpeername (0, 0, &len);]])],
+               [gl_cv_socklen_t_equiv="$t"])
+             test "$gl_cv_socklen_t_equiv" != "" && break
+           done
+           test "$gl_cv_socklen_t_equiv" != "" && break
+         done
+         if test "$gl_cv_socklen_t_equiv" = ""; then
+           AC_MSG_ERROR([Cannot find a type to use in place of socklen_t])
+         fi
+        ])
+      AC_DEFINE_UNQUOTED([socklen_t], [$gl_cv_socklen_t_equiv],
+        [type to use in place of socklen_t if not defined])],
+     [gl_SOCKET_HEADERS])])
+
+dnl On mingw32, socklen_t is in ws2tcpip.h ('int'), so we try to find
+dnl it there too.  But on Cygwin, wc2tcpip.h must not be included.  Users
+dnl of this module should use the same include pattern as gl_SOCKET_HEADERS.
+dnl When you change this macro, keep also in sync:
+dnl   - gl_CHECK_SOCKET_HEADERS,
+dnl   - the Include section of modules/socklen.
+AC_DEFUN([gl_SOCKET_HEADERS],
+[
+/* <sys/types.h> is not needed according to POSIX, but the
+   <sys/socket.h> in i386-unknown-freebsd4.10 and
+   powerpc-apple-darwin5.5 required it. */
+#include <sys/types.h>
+#if HAVE_SYS_SOCKET_H
+# include <sys/socket.h>
+#elif HAVE_WS2TCPIP_H
+# include <ws2tcpip.h>
+#endif
+])
+
+dnl Tests for the existence of the header for socket facilities.
+dnl Defines the C macros HAVE_SYS_SOCKET_H, HAVE_WS2TCPIP_H.
+dnl This macro must match gl_SOCKET_HEADERS.
+AC_DEFUN([gl_CHECK_SOCKET_HEADERS],
+  [AC_CHECK_HEADERS_ONCE([sys/socket.h])
+   if test $ac_cv_header_sys_socket_h = no; then
+     dnl We cannot use AC_CHECK_HEADERS_ONCE here, because that would make
+     dnl the check for those headers unconditional; yet cygwin reports
+     dnl that the headers are present but cannot be compiled (since on
+     dnl cygwin, all socket information should come from sys/socket.h).
+     AC_CHECK_HEADERS([ws2tcpip.h])
+   fi
+  ])
diff --git a/m4/sockpfaf.m4 b/m4/sockpfaf.m4
new file mode 100644
index 0000000..495a355
--- /dev/null
+++ b/m4/sockpfaf.m4
@@ -0,0 +1,84 @@
+# sockpfaf.m4 serial 9
+dnl Copyright (C) 2004, 2006, 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl Test for some common socket protocol families (PF_INET, PF_INET6, ...)
+dnl and some common address families (AF_INET, AF_INET6, ...).
+dnl This test assumes that a system supports an address family if and only if
+dnl it supports the corresponding protocol family.
+
+dnl From Bruno Haible.
+
+AC_DEFUN([gl_SOCKET_FAMILIES],
+[
+  AC_REQUIRE([gl_HEADER_SYS_SOCKET])
+  AC_CHECK_HEADERS_ONCE([netinet/in.h])
+
+  AC_CACHE_CHECK([for IPv4 sockets],
+    [gl_cv_socket_ipv4],
+    [AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <sys/types.h>
+#ifdef HAVE_SYS_SOCKET_H
+#include <sys/socket.h>
+#endif
+#ifdef HAVE_NETINET_IN_H
+#include <netinet/in.h>
+#endif
+#ifdef HAVE_WINSOCK2_H
+#include <winsock2.h>
+#endif]],
+[[int x = AF_INET; struct in_addr y; struct sockaddr_in z;
+ if (&x && &y && &z) return 0;]])],
+       gl_cv_socket_ipv4=yes, gl_cv_socket_ipv4=no)])
+  if test $gl_cv_socket_ipv4 = yes; then
+    AC_DEFINE([HAVE_IPV4], [1], [Define to 1 if <sys/socket.h> defines AF_INET.])
+  fi
+
+  AC_CACHE_CHECK([for IPv6 sockets],
+    [gl_cv_socket_ipv6],
+    [AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <sys/types.h>
+#ifdef HAVE_SYS_SOCKET_H
+#include <sys/socket.h>
+#endif
+#ifdef HAVE_NETINET_IN_H
+#include <netinet/in.h>
+#endif
+#ifdef HAVE_WINSOCK2_H
+#include <winsock2.h>
+#endif
+#ifdef HAVE_WS2TCPIP_H
+#include <ws2tcpip.h>
+#endif]],
+[[int x = AF_INET6; struct in6_addr y; struct sockaddr_in6 z;
+ if (&x && &y && &z) return 0;]])],
+       gl_cv_socket_ipv6=yes, gl_cv_socket_ipv6=no)])
+  if test $gl_cv_socket_ipv6 = yes; then
+    AC_DEFINE([HAVE_IPV6], [1], [Define to 1 if <sys/socket.h> defines AF_INET6.])
+  fi
+])
+
+AC_DEFUN([gl_SOCKET_FAMILY_UNIX],
+[
+  AC_REQUIRE([gl_HEADER_SYS_SOCKET])
+  AC_CHECK_HEADERS_ONCE([sys/un.h])
+
+  AC_CACHE_CHECK([for UNIX domain sockets],
+    [gl_cv_socket_unix],
+    [AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <sys/types.h>
+#ifdef HAVE_SYS_SOCKET_H
+#include <sys/socket.h>
+#endif
+#ifdef HAVE_SYS_UN_H
+#include <sys/un.h>
+#endif
+#ifdef HAVE_WINSOCK2_H
+#include <winsock2.h>
+#endif]],
+[[int x = AF_UNIX; struct sockaddr_un y;
+ if (&x && &y) return 0;]])],
+       gl_cv_socket_unix=yes, gl_cv_socket_unix=no)])
+  if test $gl_cv_socket_unix = yes; then
+    AC_DEFINE([HAVE_UNIXSOCKET], [1], [Define to 1 if <sys/socket.h> defines AF_UNIX.])
+  fi
+])
diff --git a/m4/spawn-pipe.m4 b/m4/spawn-pipe.m4
new file mode 100644
index 0000000..471f91d
--- /dev/null
+++ b/m4/spawn-pipe.m4
@@ -0,0 +1,11 @@
+# spawn-pipe.m4 serial 2
+dnl Copyright (C) 2004, 2008-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_SPAWN_PIPE],
+[
+  dnl Prerequisites of lib/spawn-pipe.c.
+  AC_REQUIRE([AC_TYPE_MODE_T])
+])
diff --git a/m4/spawn_h.m4 b/m4/spawn_h.m4
new file mode 100644
index 0000000..781f9f4
--- /dev/null
+++ b/m4/spawn_h.m4
@@ -0,0 +1,136 @@
+# spawn_h.m4 serial 18
+dnl Copyright (C) 2008-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl Written by Bruno Haible.
+
+AC_DEFUN([gl_SPAWN_H],
+[
+  dnl Use AC_REQUIRE here, so that the default behavior below is expanded
+  dnl once only, before all statements that occur in other macros.
+  AC_REQUIRE([gl_SPAWN_H_DEFAULTS])
+
+  dnl <spawn.h> is always overridden, because of GNULIB_POSIXCHECK.
+  gl_CHECK_NEXT_HEADERS([spawn.h])
+
+  if test $ac_cv_header_spawn_h = yes; then
+    HAVE_SPAWN_H=1
+    AC_CHECK_TYPES([posix_spawnattr_t], [], [HAVE_POSIX_SPAWNATTR_T=0], [[
+#include <spawn.h>
+      ]])
+    AC_CHECK_TYPES([posix_spawn_file_actions_t], [],
+      [HAVE_POSIX_SPAWN_FILE_ACTIONS_T=0], [[
+#include <spawn.h>
+      ]])
+  else
+    HAVE_SPAWN_H=0
+    HAVE_POSIX_SPAWNATTR_T=0
+    HAVE_POSIX_SPAWN_FILE_ACTIONS_T=0
+  fi
+  AC_SUBST([HAVE_SPAWN_H])
+
+  dnl Ensure the type pid_t gets defined.
+  AC_REQUIRE([AC_TYPE_PID_T])
+
+  dnl Ensure the type mode_t gets defined.
+  AC_REQUIRE([AC_TYPE_MODE_T])
+
+  AC_REQUIRE([gl_HAVE_POSIX_SPAWN])
+
+  AC_REQUIRE([AC_C_RESTRICT])
+
+  dnl Check for declarations of anything we want to poison if the
+  dnl corresponding gnulib module is not in use.
+  gl_WARN_ON_USE_PREPARE([[#include <spawn.h>
+    ]], [posix_spawn posix_spawnp posix_spawnattr_init posix_spawnattr_destroy
+    posix_spawnattr_getsigdefault posix_spawnattr_setsigdefault
+    posix_spawnattr_getsigmask posix_spawnattr_setsigmask
+    posix_spawnattr_getflags posix_spawnattr_setflags
+    posix_spawnattr_getpgroup posix_spawnattr_setpgroup
+    posix_spawnattr_getschedpolicy posix_spawnattr_setschedpolicy
+    posix_spawnattr_getschedparam posix_spawnattr_setschedparam
+    posix_spawn_file_actions_init posix_spawn_file_actions_destroy
+    posix_spawn_file_actions_addopen posix_spawn_file_actions_addclose
+    posix_spawn_file_actions_adddup2 posix_spawn_file_actions_addchdir
+    posix_spawn_file_actions_addfchdir])
+])
+
+dnl Checks whether the system has the functions posix_spawn.
+dnl Sets ac_cv_func_posix_spawn and HAVE_POSIX_SPAWN.
+AC_DEFUN([gl_HAVE_POSIX_SPAWN],
+[
+  dnl Use AC_REQUIRE here, so that the default behavior below is expanded
+  dnl once only, before all statements that occur in other macros.
+  AC_REQUIRE([gl_SPAWN_H_DEFAULTS])
+
+  LIB_POSIX_SPAWN=
+  AC_SUBST([LIB_POSIX_SPAWN])
+  gl_saved_libs=$LIBS
+    AC_SEARCH_LIBS([posix_spawn], [rt],
+                   [test "$ac_cv_search_posix_spawn" = "none required" ||
+                    LIB_POSIX_SPAWN=$ac_cv_search_posix_spawn])
+    AC_CHECK_FUNCS([posix_spawn])
+  LIBS=$gl_saved_libs
+
+  if test $ac_cv_func_posix_spawn != yes; then
+    HAVE_POSIX_SPAWN=0
+  fi
+])
+
+AC_DEFUN([gl_SPAWN_MODULE_INDICATOR],
+[
+  dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
+  AC_REQUIRE([gl_SPAWN_H_DEFAULTS])
+  gl_MODULE_INDICATOR_SET_VARIABLE([$1])
+  dnl Define it also as a C macro, for the benefit of the unit tests.
+  gl_MODULE_INDICATOR_FOR_TESTS([$1])
+])
+
+AC_DEFUN([gl_SPAWN_H_DEFAULTS],
+[
+  GNULIB_POSIX_SPAWN=0;                        AC_SUBST([GNULIB_POSIX_SPAWN])
+  GNULIB_POSIX_SPAWNP=0;                       AC_SUBST([GNULIB_POSIX_SPAWNP])
+  GNULIB_POSIX_SPAWN_FILE_ACTIONS_INIT=0;      AC_SUBST([GNULIB_POSIX_SPAWN_FILE_ACTIONS_INIT])
+  GNULIB_POSIX_SPAWN_FILE_ACTIONS_ADDCHDIR=0;  AC_SUBST([GNULIB_POSIX_SPAWN_FILE_ACTIONS_ADDCHDIR])
+  GNULIB_POSIX_SPAWN_FILE_ACTIONS_ADDCLOSE=0;  AC_SUBST([GNULIB_POSIX_SPAWN_FILE_ACTIONS_ADDCLOSE])
+  GNULIB_POSIX_SPAWN_FILE_ACTIONS_ADDDUP2=0;   AC_SUBST([GNULIB_POSIX_SPAWN_FILE_ACTIONS_ADDDUP2])
+  GNULIB_POSIX_SPAWN_FILE_ACTIONS_ADDFCHDIR=0; AC_SUBST([GNULIB_POSIX_SPAWN_FILE_ACTIONS_ADDFCHDIR])
+  GNULIB_POSIX_SPAWN_FILE_ACTIONS_ADDOPEN=0;   AC_SUBST([GNULIB_POSIX_SPAWN_FILE_ACTIONS_ADDOPEN])
+  GNULIB_POSIX_SPAWN_FILE_ACTIONS_DESTROY=0;   AC_SUBST([GNULIB_POSIX_SPAWN_FILE_ACTIONS_DESTROY])
+  GNULIB_POSIX_SPAWNATTR_INIT=0;               AC_SUBST([GNULIB_POSIX_SPAWNATTR_INIT])
+  GNULIB_POSIX_SPAWNATTR_GETFLAGS=0;           AC_SUBST([GNULIB_POSIX_SPAWNATTR_GETFLAGS])
+  GNULIB_POSIX_SPAWNATTR_SETFLAGS=0;           AC_SUBST([GNULIB_POSIX_SPAWNATTR_SETFLAGS])
+  GNULIB_POSIX_SPAWNATTR_GETPGROUP=0;          AC_SUBST([GNULIB_POSIX_SPAWNATTR_GETPGROUP])
+  GNULIB_POSIX_SPAWNATTR_SETPGROUP=0;          AC_SUBST([GNULIB_POSIX_SPAWNATTR_SETPGROUP])
+  GNULIB_POSIX_SPAWNATTR_GETSCHEDPARAM=0;      AC_SUBST([GNULIB_POSIX_SPAWNATTR_GETSCHEDPARAM])
+  GNULIB_POSIX_SPAWNATTR_SETSCHEDPARAM=0;      AC_SUBST([GNULIB_POSIX_SPAWNATTR_SETSCHEDPARAM])
+  GNULIB_POSIX_SPAWNATTR_GETSCHEDPOLICY=0;     AC_SUBST([GNULIB_POSIX_SPAWNATTR_GETSCHEDPOLICY])
+  GNULIB_POSIX_SPAWNATTR_SETSCHEDPOLICY=0;     AC_SUBST([GNULIB_POSIX_SPAWNATTR_SETSCHEDPOLICY])
+  GNULIB_POSIX_SPAWNATTR_GETSIGDEFAULT=0;      AC_SUBST([GNULIB_POSIX_SPAWNATTR_GETSIGDEFAULT])
+  GNULIB_POSIX_SPAWNATTR_SETSIGDEFAULT=0;      AC_SUBST([GNULIB_POSIX_SPAWNATTR_SETSIGDEFAULT])
+  GNULIB_POSIX_SPAWNATTR_GETSIGMASK=0;         AC_SUBST([GNULIB_POSIX_SPAWNATTR_GETSIGMASK])
+  GNULIB_POSIX_SPAWNATTR_SETSIGMASK=0;         AC_SUBST([GNULIB_POSIX_SPAWNATTR_SETSIGMASK])
+  GNULIB_POSIX_SPAWNATTR_DESTROY=0;            AC_SUBST([GNULIB_POSIX_SPAWNATTR_DESTROY])
+  dnl Assume proper GNU behavior unless another module says otherwise.
+  HAVE_POSIX_SPAWN=1;        AC_SUBST([HAVE_POSIX_SPAWN])
+  HAVE_POSIX_SPAWNATTR_T=1;  AC_SUBST([HAVE_POSIX_SPAWNATTR_T])
+  HAVE_POSIX_SPAWN_FILE_ACTIONS_T=1;
+                             AC_SUBST([HAVE_POSIX_SPAWN_FILE_ACTIONS_T])
+  HAVE_POSIX_SPAWN_FILE_ACTIONS_ADDCHDIR=1;
+                             AC_SUBST([HAVE_POSIX_SPAWN_FILE_ACTIONS_ADDCHDIR])
+  HAVE_POSIX_SPAWN_FILE_ACTIONS_ADDFCHDIR=1;
+                             AC_SUBST([HAVE_POSIX_SPAWN_FILE_ACTIONS_ADDFCHDIR])
+  REPLACE_POSIX_SPAWN=0;     AC_SUBST([REPLACE_POSIX_SPAWN])
+  REPLACE_POSIX_SPAWN_FILE_ACTIONS_ADDCHDIR=0;
+                             AC_SUBST([REPLACE_POSIX_SPAWN_FILE_ACTIONS_ADDCHDIR])
+  REPLACE_POSIX_SPAWN_FILE_ACTIONS_ADDCLOSE=0;
+                             AC_SUBST([REPLACE_POSIX_SPAWN_FILE_ACTIONS_ADDCLOSE])
+  REPLACE_POSIX_SPAWN_FILE_ACTIONS_ADDDUP2=0;
+                             AC_SUBST([REPLACE_POSIX_SPAWN_FILE_ACTIONS_ADDDUP2])
+  REPLACE_POSIX_SPAWN_FILE_ACTIONS_ADDFCHDIR=0;
+                             AC_SUBST([REPLACE_POSIX_SPAWN_FILE_ACTIONS_ADDFCHDIR])
+  REPLACE_POSIX_SPAWN_FILE_ACTIONS_ADDOPEN=0;
+                             AC_SUBST([REPLACE_POSIX_SPAWN_FILE_ACTIONS_ADDOPEN])
+])
diff --git a/m4/ssize_t.m4 b/m4/ssize_t.m4
new file mode 100644
index 0000000..6c0a588
--- /dev/null
+++ b/m4/ssize_t.m4
@@ -0,0 +1,23 @@
+# ssize_t.m4 serial 5 (gettext-0.18.2)
+dnl Copyright (C) 2001-2003, 2006, 2010-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl From Bruno Haible.
+dnl Test whether ssize_t is defined.
+
+AC_DEFUN([gt_TYPE_SSIZE_T],
+[
+  AC_CACHE_CHECK([for ssize_t], [gt_cv_ssize_t],
+    [AC_COMPILE_IFELSE(
+       [AC_LANG_PROGRAM(
+          [[#include <sys/types.h>]],
+          [[int x = sizeof (ssize_t *) + sizeof (ssize_t);
+            return !x;]])],
+       [gt_cv_ssize_t=yes], [gt_cv_ssize_t=no])])
+  if test $gt_cv_ssize_t = no; then
+    AC_DEFINE([ssize_t], [int],
+              [Define as a signed type of the same size as size_t.])
+  fi
+])
diff --git a/m4/stat-time.m4 b/m4/stat-time.m4
new file mode 100644
index 0000000..0ac3f72
--- /dev/null
+++ b/m4/stat-time.m4
@@ -0,0 +1,83 @@
+# Checks for stat-related time functions.
+
+# Copyright (C) 1998-1999, 2001, 2003, 2005-2007, 2009-2020 Free Software
+# Foundation, Inc.
+
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+dnl From Paul Eggert.
+
+# st_atim.tv_nsec - Linux, Solaris, Cygwin
+# st_atimespec.tv_nsec - FreeBSD, NetBSD, if ! defined _POSIX_SOURCE
+# st_atimensec - FreeBSD, NetBSD, if defined _POSIX_SOURCE
+# st_atim.st__tim.tv_nsec - UnixWare (at least 2.1.2 through 7.1)
+
+# st_birthtimespec - FreeBSD, NetBSD (hidden on OpenBSD 3.9, anyway)
+# st_birthtim - Cygwin 1.7.0+
+
+AC_DEFUN([gl_STAT_TIME],
+[
+  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+  AC_CHECK_HEADERS_ONCE([sys/time.h])
+
+  AC_CHECK_MEMBERS([struct stat.st_atim.tv_nsec],
+    [AC_CACHE_CHECK([whether struct stat.st_atim is of type struct timespec],
+       [ac_cv_typeof_struct_stat_st_atim_is_struct_timespec],
+       [AC_COMPILE_IFELSE([AC_LANG_PROGRAM(
+          [[
+            #include <sys/types.h>
+            #include <sys/stat.h>
+            #if HAVE_SYS_TIME_H
+            # include <sys/time.h>
+            #endif
+            #include <time.h>
+            struct timespec ts;
+            struct stat st;
+          ]],
+          [[
+            st.st_atim = ts;
+          ]])],
+          [ac_cv_typeof_struct_stat_st_atim_is_struct_timespec=yes],
+          [ac_cv_typeof_struct_stat_st_atim_is_struct_timespec=no])])
+     if test $ac_cv_typeof_struct_stat_st_atim_is_struct_timespec = yes; then
+       AC_DEFINE([TYPEOF_STRUCT_STAT_ST_ATIM_IS_STRUCT_TIMESPEC], [1],
+         [Define to 1 if the type of the st_atim member of a struct stat is
+          struct timespec.])
+     fi],
+    [AC_CHECK_MEMBERS([struct stat.st_atimespec.tv_nsec], [],
+       [AC_CHECK_MEMBERS([struct stat.st_atimensec], [],
+          [AC_CHECK_MEMBERS([struct stat.st_atim.st__tim.tv_nsec], [], [],
+             [#include <sys/types.h>
+              #include <sys/stat.h>])],
+          [#include <sys/types.h>
+           #include <sys/stat.h>])],
+       [#include <sys/types.h>
+        #include <sys/stat.h>])],
+    [#include <sys/types.h>
+     #include <sys/stat.h>])
+])
+
+# Check for st_birthtime, a feature from UFS2 (FreeBSD, NetBSD, OpenBSD, etc.)
+# and NTFS (Cygwin).
+# There was a time when this field was named st_createtime (21 June
+# 2002 to 16 July 2002) But that window is very small and applied only
+# to development code, so systems still using that configuration are
+# not supported.  See revisions 1.10 and 1.11 of FreeBSD's
+# src/sys/ufs/ufs/dinode.h.
+#
+AC_DEFUN([gl_STAT_BIRTHTIME],
+[
+  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+  AC_CHECK_HEADERS_ONCE([sys/time.h])
+  AC_CHECK_MEMBERS([struct stat.st_birthtimespec.tv_nsec], [],
+    [AC_CHECK_MEMBERS([struct stat.st_birthtimensec], [],
+      [AC_CHECK_MEMBERS([struct stat.st_birthtim.tv_nsec], [], [],
+         [#include <sys/types.h>
+          #include <sys/stat.h>])],
+       [#include <sys/types.h>
+        #include <sys/stat.h>])],
+    [#include <sys/types.h>
+     #include <sys/stat.h>])
+])
diff --git a/m4/stat.m4 b/m4/stat.m4
new file mode 100644
index 0000000..db2038f
--- /dev/null
+++ b/m4/stat.m4
@@ -0,0 +1,85 @@
+# serial 17
+
+# Copyright (C) 2009-2020 Free Software Foundation, Inc.
+#
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_STAT],
+[
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  AC_REQUIRE([gl_SYS_STAT_H_DEFAULTS])
+  AC_CHECK_FUNCS_ONCE([lstat])
+  case "$host_os" in
+    mingw*)
+      dnl On this platform, the original stat() returns st_atime, st_mtime,
+      dnl st_ctime values that are affected by the time zone.
+      REPLACE_STAT=1
+      ;;
+    *)
+      dnl AIX 7.1, Solaris 9, mingw64 mistakenly succeed on stat("file/").
+      dnl (For mingw, this is due to a broken stat() override in libmingwex.a.)
+      dnl FreeBSD 7.2 mistakenly succeeds on stat("link-to-file/").
+      AC_CACHE_CHECK([whether stat handles trailing slashes on files],
+        [gl_cv_func_stat_file_slash],
+        [touch conftest.tmp
+         # Assume that if we have lstat, we can also check symlinks.
+         if test $ac_cv_func_lstat = yes; then
+           ln -s conftest.tmp conftest.lnk
+         fi
+         AC_RUN_IFELSE(
+           [AC_LANG_PROGRAM(
+             [[#include <sys/stat.h>
+]], [[int result = 0;
+               struct stat st;
+               if (!stat ("conftest.tmp/", &st))
+                 result |= 1;
+#if HAVE_LSTAT
+               if (!stat ("conftest.lnk/", &st))
+                 result |= 2;
+#endif
+               return result;
+             ]])],
+           [gl_cv_func_stat_file_slash=yes], [gl_cv_func_stat_file_slash=no],
+           [case "$host_os" in
+                               # Guess yes on Linux systems.
+              linux-* | linux) gl_cv_func_stat_file_slash="guessing yes" ;;
+                               # Guess yes on glibc systems.
+              *-gnu* | gnu*)   gl_cv_func_stat_file_slash="guessing yes" ;;
+                               # If we don't know, obey --enable-cross-guesses.
+              *)               gl_cv_func_stat_file_slash="$gl_cross_guess_normal" ;;
+            esac
+           ])
+         rm -f conftest.tmp conftest.lnk])
+      case $gl_cv_func_stat_file_slash in
+        *no)
+          REPLACE_STAT=1
+          AC_DEFINE([REPLACE_FUNC_STAT_FILE], [1], [Define to 1 if stat needs
+            help when passed a file name with a trailing slash]);;
+      esac
+      case $host_os in
+        dnl Solaris stat can return a negative tv_nsec.
+        solaris*)
+          REPLACE_FSTAT=1 ;;
+      esac
+      ;;
+  esac
+])
+
+# Prerequisites of lib/stat.c and lib/stat-w32.c.
+AC_DEFUN([gl_PREREQ_STAT], [
+  AC_REQUIRE([gl_HEADER_SYS_STAT_H])
+  AC_REQUIRE([gl_PREREQ_STAT_W32])
+  :
+])
+
+# Prerequisites of lib/stat-w32.c.
+AC_DEFUN([gl_PREREQ_STAT_W32], [
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  case "$host_os" in
+    mingw*)
+      AC_CHECK_HEADERS([sdkddkver.h])
+      ;;
+  esac
+])
diff --git a/m4/stdalign.m4 b/m4/stdalign.m4
new file mode 100644
index 0000000..dcf778e
--- /dev/null
+++ b/m4/stdalign.m4
@@ -0,0 +1,57 @@
+# Check for stdalign.h that conforms to C11.
+
+dnl Copyright 2011-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+# Prepare for substituting <stdalign.h> if it is not supported.
+
+AC_DEFUN([gl_STDALIGN_H],
+[
+  AC_CACHE_CHECK([for working stdalign.h],
+    [gl_cv_header_working_stdalign_h],
+    [AC_COMPILE_IFELSE(
+       [AC_LANG_PROGRAM(
+          [[#include <stdalign.h>
+            #include <stddef.h>
+
+            /* Test that alignof yields a result consistent with offsetof.
+               This catches GCC bug 52023
+               <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=52023>.  */
+            #ifdef __cplusplus
+               template <class t> struct alignof_helper { char a; t b; };
+            # define ao(type) offsetof (alignof_helper<type>, b)
+            #else
+            # define ao(type) offsetof (struct { char a; type b; }, b)
+            #endif
+            char test_double[ao (double) % _Alignof (double) == 0 ? 1 : -1];
+            char test_long[ao (long int) % _Alignof (long int) == 0 ? 1 : -1];
+            char test_alignof[alignof (double) == _Alignof (double) ? 1 : -1];
+
+            /* Test _Alignas only on platforms where gnulib can help.  */
+            #if \
+                ((defined __cplusplus && 201103 <= __cplusplus) \
+                 || (defined __APPLE__ && defined __MACH__ \
+                     ? 4 < __GNUC__ + (1 <= __GNUC_MINOR__) \
+                     : __GNUC__) \
+                 || (__ia64 && (61200 <= __HP_cc || 61200 <= __HP_aCC)) \
+                 || __ICC || 0x590 <= __SUNPRO_C || 0x0600 <= __xlC__ \
+                 || 1300 <= _MSC_VER)
+              struct alignas_test { char c; char alignas (8) alignas_8; };
+              char test_alignas[offsetof (struct alignas_test, alignas_8) == 8
+                                ? 1 : -1];
+            #endif
+          ]])],
+       [gl_cv_header_working_stdalign_h=yes],
+       [gl_cv_header_working_stdalign_h=no])])
+
+  if test $gl_cv_header_working_stdalign_h = yes; then
+    STDALIGN_H=''
+  else
+    STDALIGN_H='stdalign.h'
+  fi
+
+  AC_SUBST([STDALIGN_H])
+  AM_CONDITIONAL([GL_GENERATE_STDALIGN_H], [test -n "$STDALIGN_H"])
+])
diff --git a/m4/stdbool.m4 b/m4/stdbool.m4
new file mode 100644
index 0000000..6bb087e
--- /dev/null
+++ b/m4/stdbool.m4
@@ -0,0 +1,122 @@
+# Check for stdbool.h that conforms to C99.
+
+dnl Copyright (C) 2002-2006, 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+#serial 8
+
+# Prepare for substituting <stdbool.h> if it is not supported.
+
+AC_DEFUN([AM_STDBOOL_H],
+[
+  AC_REQUIRE([AC_CHECK_HEADER_STDBOOL])
+  AC_REQUIRE([AC_CANONICAL_HOST])
+
+  dnl On some platforms, <stdbool.h> does not exist or does not conform to C99.
+  dnl On Solaris 10 with CC=cc CXX=CC, <stdbool.h> exists but is not usable
+  dnl in C++ mode (and no <cstdbool> exists). In this case, we use our
+  dnl replacement, also in C mode (for binary compatibility between C and C++).
+  if test "$ac_cv_header_stdbool_h" = yes; then
+    case "$host_os" in
+      solaris*)
+        if test -z "$GCC"; then
+          STDBOOL_H='stdbool.h'
+        else
+          STDBOOL_H=''
+        fi
+        ;;
+      *)
+        STDBOOL_H=''
+        ;;
+    esac
+  else
+    STDBOOL_H='stdbool.h'
+  fi
+  AC_SUBST([STDBOOL_H])
+  AM_CONDITIONAL([GL_GENERATE_STDBOOL_H], [test -n "$STDBOOL_H"])
+
+  if test "$ac_cv_type__Bool" = yes; then
+    HAVE__BOOL=1
+  else
+    HAVE__BOOL=0
+  fi
+  AC_SUBST([HAVE__BOOL])
+])
+
+# AM_STDBOOL_H will be renamed to gl_STDBOOL_H in the future.
+AC_DEFUN([gl_STDBOOL_H], [AM_STDBOOL_H])
+
+# This version of the macro is needed in autoconf <= 2.68.
+
+AC_DEFUN([AC_CHECK_HEADER_STDBOOL],
+  [AC_CACHE_CHECK([for stdbool.h that conforms to C99],
+     [ac_cv_header_stdbool_h],
+     [AC_COMPILE_IFELSE(
+        [AC_LANG_PROGRAM(
+           [[
+             #include <stdbool.h>
+
+             #ifdef __cplusplus
+              typedef bool Bool;
+             #else
+              typedef _Bool Bool;
+              #ifndef bool
+               "error: bool is not defined"
+              #endif
+              #ifndef false
+               "error: false is not defined"
+              #endif
+              #if false
+               "error: false is not 0"
+              #endif
+              #ifndef true
+               "error: true is not defined"
+              #endif
+              #if true != 1
+               "error: true is not 1"
+              #endif
+             #endif
+
+             #ifndef __bool_true_false_are_defined
+              "error: __bool_true_false_are_defined is not defined"
+             #endif
+
+             struct s { Bool s: 1; Bool t; bool u: 1; bool v; } s;
+
+             char a[true == 1 ? 1 : -1];
+             char b[false == 0 ? 1 : -1];
+             char c[__bool_true_false_are_defined == 1 ? 1 : -1];
+             char d[(bool) 0.5 == true ? 1 : -1];
+             /* See body of main program for 'e'.  */
+             char f[(Bool) 0.0 == false ? 1 : -1];
+             char g[true];
+             char h[sizeof (Bool)];
+             char i[sizeof s.t];
+             enum { j = false, k = true, l = false * true, m = true * 256 };
+             /* The following fails for
+                HP aC++/ANSI C B3910B A.05.55 [Dec 04 2003]. */
+             Bool n[m];
+             char o[sizeof n == m * sizeof n[0] ? 1 : -1];
+             char p[-1 - (Bool) 0 < 0 && -1 - (bool) 0 < 0 ? 1 : -1];
+             /* Catch a bug in an HP-UX C compiler.  See
+                https://gcc.gnu.org/ml/gcc-patches/2003-12/msg02303.html
+                https://lists.gnu.org/r/bug-coreutils/2005-11/msg00161.html
+              */
+             Bool q = true;
+             Bool *pq = &q;
+             bool *qq = &q;
+           ]],
+           [[
+             bool e = &s;
+             *pq |= q; *pq |= ! q;
+             *qq |= q; *qq |= ! q;
+             /* Refer to every declared value, to avoid compiler optimizations.  */
+             return (!a + !b + !c + !d + !e + !f + !g + !h + !i + !!j + !k + !!l
+                     + !m + !n + !o + !p + !q + !pq + !qq);
+           ]])],
+        [ac_cv_header_stdbool_h=yes],
+        [ac_cv_header_stdbool_h=no])])
+   AC_CHECK_TYPES([_Bool])
+])
diff --git a/m4/stddef_h.m4 b/m4/stddef_h.m4
new file mode 100644
index 0000000..d8bc8ff
--- /dev/null
+++ b/m4/stddef_h.m4
@@ -0,0 +1,72 @@
+dnl A placeholder for <stddef.h>, for platforms that have issues.
+# stddef_h.m4 serial 7
+dnl Copyright (C) 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_STDDEF_H],
+[
+  AC_REQUIRE([gl_STDDEF_H_DEFAULTS])
+  AC_REQUIRE([gt_TYPE_WCHAR_T])
+  STDDEF_H=
+
+  dnl Test whether the type max_align_t exists and whether its alignment
+  dnl "is as great as is supported by the implementation in all contexts".
+  AC_CACHE_CHECK([for good max_align_t],
+    [gl_cv_type_max_align_t],
+    [AC_COMPILE_IFELSE(
+       [AC_LANG_PROGRAM(
+          [[#include <stddef.h>
+            unsigned int s = sizeof (max_align_t);
+            #if defined __GNUC__ || defined __clang__ || defined __IBM__ALIGNOF__
+            int check1[2 * (__alignof__ (double) <= __alignof__ (max_align_t)) - 1];
+            int check2[2 * (__alignof__ (long double) <= __alignof__ (max_align_t)) - 1];
+            #endif
+          ]])],
+       [gl_cv_type_max_align_t=yes],
+       [gl_cv_type_max_align_t=no])
+    ])
+  if test $gl_cv_type_max_align_t = no; then
+    HAVE_MAX_ALIGN_T=0
+    STDDEF_H=stddef.h
+  fi
+
+  if test $gt_cv_c_wchar_t = no; then
+    HAVE_WCHAR_T=0
+    STDDEF_H=stddef.h
+  fi
+
+  AC_CACHE_CHECK([whether NULL can be used in arbitrary expressions],
+    [gl_cv_decl_null_works],
+    [AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <stddef.h>
+      int test[2 * (sizeof NULL == sizeof (void *)) -1];
+]])],
+      [gl_cv_decl_null_works=yes],
+      [gl_cv_decl_null_works=no])])
+  if test $gl_cv_decl_null_works = no; then
+    REPLACE_NULL=1
+    STDDEF_H=stddef.h
+  fi
+
+  AC_SUBST([STDDEF_H])
+  AM_CONDITIONAL([GL_GENERATE_STDDEF_H], [test -n "$STDDEF_H"])
+  if test -n "$STDDEF_H"; then
+    gl_NEXT_HEADERS([stddef.h])
+  fi
+])
+
+AC_DEFUN([gl_STDDEF_MODULE_INDICATOR],
+[
+  dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
+  AC_REQUIRE([gl_STDDEF_H_DEFAULTS])
+  gl_MODULE_INDICATOR_SET_VARIABLE([$1])
+])
+
+AC_DEFUN([gl_STDDEF_H_DEFAULTS],
+[
+  dnl Assume proper GNU behavior unless another module says otherwise.
+  REPLACE_NULL=0;                AC_SUBST([REPLACE_NULL])
+  HAVE_MAX_ALIGN_T=1;            AC_SUBST([HAVE_MAX_ALIGN_T])
+  HAVE_WCHAR_T=1;                AC_SUBST([HAVE_WCHAR_T])
+])
diff --git a/m4/stdint.m4 b/m4/stdint.m4
new file mode 100644
index 0000000..adaea3e
--- /dev/null
+++ b/m4/stdint.m4
@@ -0,0 +1,533 @@
+# stdint.m4 serial 58
+dnl Copyright (C) 2001-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl From Paul Eggert and Bruno Haible.
+dnl Test whether <stdint.h> is supported or must be substituted.
+
+AC_PREREQ([2.61])
+
+AC_DEFUN_ONCE([gl_STDINT_H],
+[
+  AC_PREREQ([2.59])dnl
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+
+  AC_REQUIRE([gl_LIMITS_H])
+  AC_REQUIRE([gt_TYPE_WINT_T])
+
+  dnl For backward compatibility. Some packages may still be testing these
+  dnl macros.
+  AC_DEFINE([HAVE_LONG_LONG_INT], [1],
+    [Define to 1 if the system has the type 'long long int'.])
+  AC_DEFINE([HAVE_UNSIGNED_LONG_LONG_INT], [1],
+    [Define to 1 if the system has the type 'unsigned long long int'.])
+
+  dnl Check for <wchar.h>, in the same way as gl_WCHAR_H does.
+  AC_CHECK_HEADERS_ONCE([wchar.h])
+  if test $ac_cv_header_wchar_h = yes; then
+    HAVE_WCHAR_H=1
+  else
+    HAVE_WCHAR_H=0
+  fi
+  AC_SUBST([HAVE_WCHAR_H])
+
+  dnl Check for <inttypes.h>.
+  AC_CHECK_HEADERS_ONCE([inttypes.h])
+  if test $ac_cv_header_inttypes_h = yes; then
+    HAVE_INTTYPES_H=1
+  else
+    HAVE_INTTYPES_H=0
+  fi
+  AC_SUBST([HAVE_INTTYPES_H])
+
+  dnl Check for <sys/types.h>.
+  AC_CHECK_HEADERS_ONCE([sys/types.h])
+  if test $ac_cv_header_sys_types_h = yes; then
+    HAVE_SYS_TYPES_H=1
+  else
+    HAVE_SYS_TYPES_H=0
+  fi
+  AC_SUBST([HAVE_SYS_TYPES_H])
+
+  gl_CHECK_NEXT_HEADERS([stdint.h])
+  if test $ac_cv_header_stdint_h = yes; then
+    HAVE_STDINT_H=1
+  else
+    HAVE_STDINT_H=0
+  fi
+  AC_SUBST([HAVE_STDINT_H])
+
+  dnl Now see whether we need a substitute <stdint.h>.
+  if test $ac_cv_header_stdint_h = yes; then
+    AC_CACHE_CHECK([whether stdint.h conforms to C99],
+      [gl_cv_header_working_stdint_h],
+      [gl_cv_header_working_stdint_h=no
+       AC_COMPILE_IFELSE([
+         AC_LANG_PROGRAM([[
+#define _GL_JUST_INCLUDE_SYSTEM_STDINT_H 1 /* work if build isn't clean */
+#define __STDC_CONSTANT_MACROS 1
+#define __STDC_LIMIT_MACROS 1
+#include <stdint.h>
+/* Dragonfly defines WCHAR_MIN, WCHAR_MAX only in <wchar.h>.  */
+#if !(defined WCHAR_MIN && defined WCHAR_MAX)
+#error "WCHAR_MIN, WCHAR_MAX not defined in <stdint.h>"
+#endif
+]
+gl_STDINT_INCLUDES
+[
+#ifdef INT8_MAX
+int8_t a1 = INT8_MAX;
+int8_t a1min = INT8_MIN;
+#endif
+#ifdef INT16_MAX
+int16_t a2 = INT16_MAX;
+int16_t a2min = INT16_MIN;
+#endif
+#ifdef INT32_MAX
+int32_t a3 = INT32_MAX;
+int32_t a3min = INT32_MIN;
+#endif
+#ifdef INT64_MAX
+int64_t a4 = INT64_MAX;
+int64_t a4min = INT64_MIN;
+#endif
+#ifdef UINT8_MAX
+uint8_t b1 = UINT8_MAX;
+#else
+typedef int b1[(unsigned char) -1 != 255 ? 1 : -1];
+#endif
+#ifdef UINT16_MAX
+uint16_t b2 = UINT16_MAX;
+#endif
+#ifdef UINT32_MAX
+uint32_t b3 = UINT32_MAX;
+#endif
+#ifdef UINT64_MAX
+uint64_t b4 = UINT64_MAX;
+#endif
+int_least8_t c1 = INT8_C (0x7f);
+int_least8_t c1max = INT_LEAST8_MAX;
+int_least8_t c1min = INT_LEAST8_MIN;
+int_least16_t c2 = INT16_C (0x7fff);
+int_least16_t c2max = INT_LEAST16_MAX;
+int_least16_t c2min = INT_LEAST16_MIN;
+int_least32_t c3 = INT32_C (0x7fffffff);
+int_least32_t c3max = INT_LEAST32_MAX;
+int_least32_t c3min = INT_LEAST32_MIN;
+int_least64_t c4 = INT64_C (0x7fffffffffffffff);
+int_least64_t c4max = INT_LEAST64_MAX;
+int_least64_t c4min = INT_LEAST64_MIN;
+uint_least8_t d1 = UINT8_C (0xff);
+uint_least8_t d1max = UINT_LEAST8_MAX;
+uint_least16_t d2 = UINT16_C (0xffff);
+uint_least16_t d2max = UINT_LEAST16_MAX;
+uint_least32_t d3 = UINT32_C (0xffffffff);
+uint_least32_t d3max = UINT_LEAST32_MAX;
+uint_least64_t d4 = UINT64_C (0xffffffffffffffff);
+uint_least64_t d4max = UINT_LEAST64_MAX;
+int_fast8_t e1 = INT_FAST8_MAX;
+int_fast8_t e1min = INT_FAST8_MIN;
+int_fast16_t e2 = INT_FAST16_MAX;
+int_fast16_t e2min = INT_FAST16_MIN;
+int_fast32_t e3 = INT_FAST32_MAX;
+int_fast32_t e3min = INT_FAST32_MIN;
+int_fast64_t e4 = INT_FAST64_MAX;
+int_fast64_t e4min = INT_FAST64_MIN;
+uint_fast8_t f1 = UINT_FAST8_MAX;
+uint_fast16_t f2 = UINT_FAST16_MAX;
+uint_fast32_t f3 = UINT_FAST32_MAX;
+uint_fast64_t f4 = UINT_FAST64_MAX;
+#ifdef INTPTR_MAX
+intptr_t g = INTPTR_MAX;
+intptr_t gmin = INTPTR_MIN;
+#endif
+#ifdef UINTPTR_MAX
+uintptr_t h = UINTPTR_MAX;
+#endif
+intmax_t i = INTMAX_MAX;
+uintmax_t j = UINTMAX_MAX;
+
+/* Check that SIZE_MAX has the correct type, if possible.  */
+#if 201112 <= __STDC_VERSION__
+int k = _Generic (SIZE_MAX, size_t: 0);
+#elif (2 <= __GNUC__ || 4 <= __clang_major__ || defined __IBM__TYPEOF__ \
+       || (0x5110 <= __SUNPRO_C && !__STDC__))
+extern size_t k;
+extern __typeof__ (SIZE_MAX) k;
+#endif
+
+#include <limits.h> /* for CHAR_BIT */
+#define TYPE_MINIMUM(t) \
+  ((t) ((t) 0 < (t) -1 ? (t) 0 : ~ TYPE_MAXIMUM (t)))
+#define TYPE_MAXIMUM(t) \
+  ((t) ((t) 0 < (t) -1 \
+        ? (t) -1 \
+        : ((((t) 1 << (sizeof (t) * CHAR_BIT - 2)) - 1) * 2 + 1)))
+struct s {
+  int check_PTRDIFF:
+      PTRDIFF_MIN == TYPE_MINIMUM (ptrdiff_t)
+      && PTRDIFF_MAX == TYPE_MAXIMUM (ptrdiff_t)
+      ? 1 : -1;
+  /* Detect bug in FreeBSD 6.0 / ia64.  */
+  int check_SIG_ATOMIC:
+      SIG_ATOMIC_MIN == TYPE_MINIMUM (sig_atomic_t)
+      && SIG_ATOMIC_MAX == TYPE_MAXIMUM (sig_atomic_t)
+      ? 1 : -1;
+  int check_SIZE: SIZE_MAX == TYPE_MAXIMUM (size_t) ? 1 : -1;
+  int check_WCHAR:
+      WCHAR_MIN == TYPE_MINIMUM (wchar_t)
+      && WCHAR_MAX == TYPE_MAXIMUM (wchar_t)
+      ? 1 : -1;
+  /* Detect bug in mingw.  */
+  int check_WINT:
+      WINT_MIN == TYPE_MINIMUM (wint_t)
+      && WINT_MAX == TYPE_MAXIMUM (wint_t)
+      ? 1 : -1;
+
+  /* Detect bugs in glibc 2.4 and Solaris 10 stdint.h, among others.  */
+  int check_UINT8_C:
+        (-1 < UINT8_C (0)) == (-1 < (uint_least8_t) 0) ? 1 : -1;
+  int check_UINT16_C:
+        (-1 < UINT16_C (0)) == (-1 < (uint_least16_t) 0) ? 1 : -1;
+
+  /* Detect bugs in OpenBSD 3.9 stdint.h.  */
+#ifdef UINT8_MAX
+  int check_uint8: (uint8_t) -1 == UINT8_MAX ? 1 : -1;
+#endif
+#ifdef UINT16_MAX
+  int check_uint16: (uint16_t) -1 == UINT16_MAX ? 1 : -1;
+#endif
+#ifdef UINT32_MAX
+  int check_uint32: (uint32_t) -1 == UINT32_MAX ? 1 : -1;
+#endif
+#ifdef UINT64_MAX
+  int check_uint64: (uint64_t) -1 == UINT64_MAX ? 1 : -1;
+#endif
+  int check_uint_least8: (uint_least8_t) -1 == UINT_LEAST8_MAX ? 1 : -1;
+  int check_uint_least16: (uint_least16_t) -1 == UINT_LEAST16_MAX ? 1 : -1;
+  int check_uint_least32: (uint_least32_t) -1 == UINT_LEAST32_MAX ? 1 : -1;
+  int check_uint_least64: (uint_least64_t) -1 == UINT_LEAST64_MAX ? 1 : -1;
+  int check_uint_fast8: (uint_fast8_t) -1 == UINT_FAST8_MAX ? 1 : -1;
+  int check_uint_fast16: (uint_fast16_t) -1 == UINT_FAST16_MAX ? 1 : -1;
+  int check_uint_fast32: (uint_fast32_t) -1 == UINT_FAST32_MAX ? 1 : -1;
+  int check_uint_fast64: (uint_fast64_t) -1 == UINT_FAST64_MAX ? 1 : -1;
+  int check_uintptr: (uintptr_t) -1 == UINTPTR_MAX ? 1 : -1;
+  int check_uintmax: (uintmax_t) -1 == UINTMAX_MAX ? 1 : -1;
+  int check_size: (size_t) -1 == SIZE_MAX ? 1 : -1;
+};
+         ]])],
+         [dnl Determine whether the various *_MIN, *_MAX macros are usable
+          dnl in preprocessor expression. We could do it by compiling a test
+          dnl program for each of these macros. It is faster to run a program
+          dnl that inspects the macro expansion.
+          dnl This detects a bug on HP-UX 11.23/ia64.
+          AC_RUN_IFELSE([
+            AC_LANG_PROGRAM([[
+#define _GL_JUST_INCLUDE_SYSTEM_STDINT_H 1 /* work if build isn't clean */
+#define __STDC_CONSTANT_MACROS 1
+#define __STDC_LIMIT_MACROS 1
+#include <stdint.h>
+]
+gl_STDINT_INCLUDES
+[
+#include <stdio.h>
+#include <string.h>
+#define MVAL(macro) MVAL1(macro)
+#define MVAL1(expression) #expression
+static const char *macro_values[] =
+  {
+#ifdef INT8_MAX
+    MVAL (INT8_MAX),
+#endif
+#ifdef INT16_MAX
+    MVAL (INT16_MAX),
+#endif
+#ifdef INT32_MAX
+    MVAL (INT32_MAX),
+#endif
+#ifdef INT64_MAX
+    MVAL (INT64_MAX),
+#endif
+#ifdef UINT8_MAX
+    MVAL (UINT8_MAX),
+#endif
+#ifdef UINT16_MAX
+    MVAL (UINT16_MAX),
+#endif
+#ifdef UINT32_MAX
+    MVAL (UINT32_MAX),
+#endif
+#ifdef UINT64_MAX
+    MVAL (UINT64_MAX),
+#endif
+    NULL
+  };
+]], [[
+  const char **mv;
+  for (mv = macro_values; *mv != NULL; mv++)
+    {
+      const char *value = *mv;
+      /* Test whether it looks like a cast expression.  */
+      if (strncmp (value, "((unsigned int)"/*)*/, 15) == 0
+          || strncmp (value, "((unsigned short)"/*)*/, 17) == 0
+          || strncmp (value, "((unsigned char)"/*)*/, 16) == 0
+          || strncmp (value, "((int)"/*)*/, 6) == 0
+          || strncmp (value, "((signed short)"/*)*/, 15) == 0
+          || strncmp (value, "((signed char)"/*)*/, 14) == 0)
+        return mv - macro_values + 1;
+    }
+  return 0;
+]])],
+              [gl_cv_header_working_stdint_h=yes],
+              [],
+              [case "$host_os" in
+                         # Guess yes on native Windows.
+                 mingw*) gl_cv_header_working_stdint_h="guessing yes" ;;
+                         # In general, assume it works.
+                 *)      gl_cv_header_working_stdint_h="guessing yes" ;;
+               esac
+              ])
+         ])
+      ])
+  fi
+
+  HAVE_C99_STDINT_H=0
+  HAVE_SYS_BITYPES_H=0
+  HAVE_SYS_INTTYPES_H=0
+  STDINT_H=stdint.h
+  case "$gl_cv_header_working_stdint_h" in
+    *yes)
+      HAVE_C99_STDINT_H=1
+      dnl Now see whether the system <stdint.h> works without
+      dnl __STDC_CONSTANT_MACROS/__STDC_LIMIT_MACROS defined.
+      dnl If not, there would be problems when stdint.h is included from C++.
+      AC_CACHE_CHECK([whether stdint.h works without ISO C predefines],
+        [gl_cv_header_stdint_without_STDC_macros],
+        [gl_cv_header_stdint_without_STDC_macros=no
+         AC_COMPILE_IFELSE([
+           AC_LANG_PROGRAM([[
+#define _GL_JUST_INCLUDE_SYSTEM_STDINT_H 1 /* work if build isn't clean */
+#include <stdint.h>
+]
+gl_STDINT_INCLUDES
+[
+intmax_t im = INTMAX_MAX;
+int32_t i32 = INT32_C (0x7fffffff);
+           ]])],
+           [gl_cv_header_stdint_without_STDC_macros=yes])
+        ])
+
+      if test $gl_cv_header_stdint_without_STDC_macros = no; then
+        AC_DEFINE([__STDC_CONSTANT_MACROS], [1],
+          [Define to 1 if the system <stdint.h> predates C++11.])
+        AC_DEFINE([__STDC_LIMIT_MACROS], [1],
+          [Define to 1 if the system <stdint.h> predates C++11.])
+      fi
+      AC_CACHE_CHECK([whether stdint.h has UINTMAX_WIDTH etc.],
+        [gl_cv_header_stdint_width],
+        [gl_cv_header_stdint_width=no
+         AC_COMPILE_IFELSE(
+           [AC_LANG_PROGRAM([[
+              /* Work if build is not clean.  */
+              #define _GL_JUST_INCLUDE_SYSTEM_STDINT_H 1
+              #ifndef __STDC_WANT_IEC_60559_BFP_EXT__
+               #define __STDC_WANT_IEC_60559_BFP_EXT__ 1
+              #endif
+              #include <stdint.h>
+              ]gl_STDINT_INCLUDES[
+              int iw = UINTMAX_WIDTH;
+              ]])],
+           [gl_cv_header_stdint_width=yes])])
+      if test "$gl_cv_header_stdint_width" = yes; then
+        STDINT_H=
+      fi
+      ;;
+    *)
+      dnl Check for <sys/inttypes.h>, and for
+      dnl <sys/bitypes.h> (used in Linux libc4 >= 4.6.7 and libc5).
+      AC_CHECK_HEADERS([sys/inttypes.h sys/bitypes.h])
+      if test $ac_cv_header_sys_inttypes_h = yes; then
+        HAVE_SYS_INTTYPES_H=1
+      fi
+      if test $ac_cv_header_sys_bitypes_h = yes; then
+        HAVE_SYS_BITYPES_H=1
+      fi
+      gl_STDINT_TYPE_PROPERTIES
+      ;;
+  esac
+
+  dnl The substitute stdint.h needs the substitute limit.h's _GL_INTEGER_WIDTH.
+  gl_REPLACE_LIMITS_H
+
+  AC_SUBST([HAVE_C99_STDINT_H])
+  AC_SUBST([HAVE_SYS_BITYPES_H])
+  AC_SUBST([HAVE_SYS_INTTYPES_H])
+  AC_SUBST([STDINT_H])
+  AM_CONDITIONAL([GL_GENERATE_STDINT_H], [test -n "$STDINT_H"])
+])
+
+dnl gl_STDINT_BITSIZEOF(TYPES, INCLUDES)
+dnl Determine the size of each of the given types in bits.
+AC_DEFUN([gl_STDINT_BITSIZEOF],
+[
+  dnl Use a shell loop, to avoid bloating configure, and
+  dnl - extra AH_TEMPLATE calls, so that autoheader knows what to put into
+  dnl   config.h.in,
+  dnl - extra AC_SUBST calls, so that the right substitutions are made.
+  m4_foreach_w([gltype], [$1],
+    [AH_TEMPLATE([BITSIZEOF_]m4_translit(gltype,[abcdefghijklmnopqrstuvwxyz ],[ABCDEFGHIJKLMNOPQRSTUVWXYZ_]),
+       [Define to the number of bits in type ']gltype['.])])
+  for gltype in $1 ; do
+    AC_CACHE_CHECK([for bit size of $gltype], [gl_cv_bitsizeof_${gltype}],
+      [AC_COMPUTE_INT([result], [sizeof ($gltype) * CHAR_BIT],
+         [$2
+#include <limits.h>], [result=unknown])
+       eval gl_cv_bitsizeof_${gltype}=\$result
+      ])
+    eval result=\$gl_cv_bitsizeof_${gltype}
+    if test $result = unknown; then
+      dnl Use a nonempty default, because some compilers, such as IRIX 5 cc,
+      dnl do a syntax check even on unused #if conditions and give an error
+      dnl on valid C code like this:
+      dnl   #if 0
+      dnl   # if  > 32
+      dnl   # endif
+      dnl   #endif
+      result=0
+    fi
+    GLTYPE=`echo "$gltype" | tr 'abcdefghijklmnopqrstuvwxyz ' 'ABCDEFGHIJKLMNOPQRSTUVWXYZ_'`
+    AC_DEFINE_UNQUOTED([BITSIZEOF_${GLTYPE}], [$result])
+    eval BITSIZEOF_${GLTYPE}=\$result
+  done
+  m4_foreach_w([gltype], [$1],
+    [AC_SUBST([BITSIZEOF_]m4_translit(gltype,[abcdefghijklmnopqrstuvwxyz ],[ABCDEFGHIJKLMNOPQRSTUVWXYZ_]))])
+])
+
+dnl gl_CHECK_TYPES_SIGNED(TYPES, INCLUDES)
+dnl Determine the signedness of each of the given types.
+dnl Define HAVE_SIGNED_TYPE if type is signed.
+AC_DEFUN([gl_CHECK_TYPES_SIGNED],
+[
+  dnl Use a shell loop, to avoid bloating configure, and
+  dnl - extra AH_TEMPLATE calls, so that autoheader knows what to put into
+  dnl   config.h.in,
+  dnl - extra AC_SUBST calls, so that the right substitutions are made.
+  m4_foreach_w([gltype], [$1],
+    [AH_TEMPLATE([HAVE_SIGNED_]m4_translit(gltype,[abcdefghijklmnopqrstuvwxyz ],[ABCDEFGHIJKLMNOPQRSTUVWXYZ_]),
+       [Define to 1 if ']gltype[' is a signed integer type.])])
+  for gltype in $1 ; do
+    AC_CACHE_CHECK([whether $gltype is signed], [gl_cv_type_${gltype}_signed],
+      [AC_COMPILE_IFELSE(
+         [AC_LANG_PROGRAM([$2[
+            int verify[2 * (($gltype) -1 < ($gltype) 0) - 1];]])],
+         result=yes, result=no)
+       eval gl_cv_type_${gltype}_signed=\$result
+      ])
+    eval result=\$gl_cv_type_${gltype}_signed
+    GLTYPE=`echo $gltype | tr 'abcdefghijklmnopqrstuvwxyz ' 'ABCDEFGHIJKLMNOPQRSTUVWXYZ_'`
+    if test "$result" = yes; then
+      AC_DEFINE_UNQUOTED([HAVE_SIGNED_${GLTYPE}], [1])
+      eval HAVE_SIGNED_${GLTYPE}=1
+    else
+      eval HAVE_SIGNED_${GLTYPE}=0
+    fi
+  done
+  m4_foreach_w([gltype], [$1],
+    [AC_SUBST([HAVE_SIGNED_]m4_translit(gltype,[abcdefghijklmnopqrstuvwxyz ],[ABCDEFGHIJKLMNOPQRSTUVWXYZ_]))])
+])
+
+dnl gl_INTEGER_TYPE_SUFFIX(TYPES, INCLUDES)
+dnl Determine the suffix to use for integer constants of the given types.
+dnl Define t_SUFFIX for each such type.
+AC_DEFUN([gl_INTEGER_TYPE_SUFFIX],
+[
+  dnl Use a shell loop, to avoid bloating configure, and
+  dnl - extra AH_TEMPLATE calls, so that autoheader knows what to put into
+  dnl   config.h.in,
+  dnl - extra AC_SUBST calls, so that the right substitutions are made.
+  m4_foreach_w([gltype], [$1],
+    [AH_TEMPLATE(m4_translit(gltype,[abcdefghijklmnopqrstuvwxyz ],[ABCDEFGHIJKLMNOPQRSTUVWXYZ_])[_SUFFIX],
+       [Define to l, ll, u, ul, ull, etc., as suitable for
+        constants of type ']gltype['.])])
+  for gltype in $1 ; do
+    AC_CACHE_CHECK([for $gltype integer literal suffix],
+      [gl_cv_type_${gltype}_suffix],
+      [eval gl_cv_type_${gltype}_suffix=no
+       eval result=\$gl_cv_type_${gltype}_signed
+       if test "$result" = yes; then
+         glsufu=
+       else
+         glsufu=u
+       fi
+       for glsuf in "$glsufu" ${glsufu}l ${glsufu}ll ${glsufu}i64; do
+         case $glsuf in
+           '')  gltype1='int';;
+           l)   gltype1='long int';;
+           ll)  gltype1='long long int';;
+           i64) gltype1='__int64';;
+           u)   gltype1='unsigned int';;
+           ul)  gltype1='unsigned long int';;
+           ull) gltype1='unsigned long long int';;
+           ui64)gltype1='unsigned __int64';;
+         esac
+         AC_COMPILE_IFELSE(
+           [AC_LANG_PROGRAM([$2[
+              extern $gltype foo;
+              extern $gltype1 foo;]])],
+           [eval gl_cv_type_${gltype}_suffix=\$glsuf])
+         eval result=\$gl_cv_type_${gltype}_suffix
+         test "$result" != no && break
+       done])
+    GLTYPE=`echo $gltype | tr 'abcdefghijklmnopqrstuvwxyz ' 'ABCDEFGHIJKLMNOPQRSTUVWXYZ_'`
+    eval result=\$gl_cv_type_${gltype}_suffix
+    test "$result" = no && result=
+    eval ${GLTYPE}_SUFFIX=\$result
+    AC_DEFINE_UNQUOTED([${GLTYPE}_SUFFIX], [$result])
+  done
+  m4_foreach_w([gltype], [$1],
+    [AC_SUBST(m4_translit(gltype,[abcdefghijklmnopqrstuvwxyz ],[ABCDEFGHIJKLMNOPQRSTUVWXYZ_])[_SUFFIX])])
+])
+
+dnl gl_STDINT_INCLUDES
+AC_DEFUN([gl_STDINT_INCLUDES],
+[[
+  #include <stddef.h>
+  #include <signal.h>
+  #if HAVE_WCHAR_H
+  # include <wchar.h>
+  #endif
+]])
+
+dnl gl_STDINT_TYPE_PROPERTIES
+dnl Compute HAVE_SIGNED_t, BITSIZEOF_t and t_SUFFIX, for all the types t
+dnl of interest to stdint.in.h.
+AC_DEFUN([gl_STDINT_TYPE_PROPERTIES],
+[
+  AC_REQUIRE([gl_MULTIARCH])
+  if test $APPLE_UNIVERSAL_BUILD = 0; then
+    gl_STDINT_BITSIZEOF([ptrdiff_t size_t],
+      [gl_STDINT_INCLUDES])
+  fi
+  gl_STDINT_BITSIZEOF([sig_atomic_t wchar_t wint_t],
+    [gl_STDINT_INCLUDES])
+  gl_CHECK_TYPES_SIGNED([sig_atomic_t wchar_t wint_t],
+    [gl_STDINT_INCLUDES])
+  gl_cv_type_ptrdiff_t_signed=yes
+  gl_cv_type_size_t_signed=no
+  if test $APPLE_UNIVERSAL_BUILD = 0; then
+    gl_INTEGER_TYPE_SUFFIX([ptrdiff_t size_t],
+      [gl_STDINT_INCLUDES])
+  fi
+  gl_INTEGER_TYPE_SUFFIX([sig_atomic_t wchar_t wint_t],
+    [gl_STDINT_INCLUDES])
+
+  dnl If wint_t is smaller than 'int', it cannot satisfy the ISO C 99
+  dnl requirement that wint_t is "unchanged by default argument promotions".
+  dnl In this case gnulib's <wchar.h> and <wctype.h> override wint_t.
+  dnl Set the variable BITSIZEOF_WINT_T accordingly.
+  if test $GNULIB_OVERRIDES_WINT_T = 1; then
+    BITSIZEOF_WINT_T=32
+  fi
+])
diff --git a/m4/stdint_h.m4 b/m4/stdint_h.m4
new file mode 100644
index 0000000..9df9e04
--- /dev/null
+++ b/m4/stdint_h.m4
@@ -0,0 +1,27 @@
+# stdint_h.m4 serial 9
+dnl Copyright (C) 1997-2004, 2006, 2008-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl From Paul Eggert.
+
+# Define HAVE_STDINT_H_WITH_UINTMAX if <stdint.h> exists,
+# doesn't clash with <sys/types.h>, and declares uintmax_t.
+
+AC_DEFUN([gl_AC_HEADER_STDINT_H],
+[
+  AC_CACHE_CHECK([for stdint.h], [gl_cv_header_stdint_h],
+    [AC_COMPILE_IFELSE(
+       [AC_LANG_PROGRAM(
+          [[#include <sys/types.h>
+            #include <stdint.h>]],
+          [[uintmax_t i = (uintmax_t) -1; return !i;]])],
+       [gl_cv_header_stdint_h=yes],
+       [gl_cv_header_stdint_h=no])])
+  if test $gl_cv_header_stdint_h = yes; then
+    AC_DEFINE_UNQUOTED([HAVE_STDINT_H_WITH_UINTMAX], [1],
+      [Define if <stdint.h> exists, doesn't clash with <sys/types.h>,
+       and declares uintmax_t. ])
+  fi
+])
diff --git a/m4/stdio_h.m4 b/m4/stdio_h.m4
new file mode 100644
index 0000000..54026c3
--- /dev/null
+++ b/m4/stdio_h.m4
@@ -0,0 +1,240 @@
+# stdio_h.m4 serial 52
+dnl Copyright (C) 2007-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_STDIO_H],
+[
+  AH_VERBATIM([MINGW_ANSI_STDIO],
+[/* Use GNU style printf and scanf.  */
+#ifndef __USE_MINGW_ANSI_STDIO
+# undef __USE_MINGW_ANSI_STDIO
+#endif
+])
+  AC_DEFINE([__USE_MINGW_ANSI_STDIO])
+  AC_REQUIRE([gl_STDIO_H_DEFAULTS])
+  gl_NEXT_HEADERS([stdio.h])
+
+  dnl Determine whether __USE_MINGW_ANSI_STDIO makes printf and
+  dnl inttypes.h behave like gnu instead of system; we must give our
+  dnl printf wrapper the right attribute to match.
+  AC_CACHE_CHECK([which flavor of printf attribute matches inttypes macros],
+    [gl_cv_func_printf_attribute_flavor],
+    [AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
+       #define __STDC_FORMAT_MACROS 1
+       #include <stdio.h>
+       #include <inttypes.h>
+       /* For non-mingw systems, compilation will trivially succeed.
+          For mingw, compilation will succeed for older mingw (system
+          printf, "I64d") and fail for newer mingw (gnu printf, "lld"). */
+       #if (defined _WIN32 && ! defined __CYGWIN__) && \
+         (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 4))
+       extern char PRIdMAX_probe[sizeof PRIdMAX == sizeof "I64d" ? 1 : -1];
+       #endif
+      ]])], [gl_cv_func_printf_attribute_flavor=system],
+      [gl_cv_func_printf_attribute_flavor=gnu])])
+  if test "$gl_cv_func_printf_attribute_flavor" = gnu; then
+    AC_DEFINE([GNULIB_PRINTF_ATTRIBUTE_FLAVOR_GNU], [1],
+      [Define to 1 if printf and friends should be labeled with
+       attribute "__gnu_printf__" instead of "__printf__"])
+  fi
+
+  dnl No need to create extra modules for these functions. Everyone who uses
+  dnl <stdio.h> likely needs them.
+  GNULIB_FSCANF=1
+  gl_MODULE_INDICATOR([fscanf])
+  GNULIB_SCANF=1
+  gl_MODULE_INDICATOR([scanf])
+  GNULIB_FGETC=1
+  GNULIB_GETC=1
+  GNULIB_GETCHAR=1
+  GNULIB_FGETS=1
+  GNULIB_FREAD=1
+  dnl This ifdef is necessary to avoid an error "missing file lib/stdio-read.c"
+  dnl "expected source file, required through AC_LIBSOURCES, not found". It is
+  dnl also an optimization, to avoid performing a configure check whose result
+  dnl is not used. But it does not make the test of GNULIB_STDIO_H_NONBLOCKING
+  dnl or GNULIB_NONBLOCKING redundant.
+  m4_ifdef([gl_NONBLOCKING_IO], [
+    gl_NONBLOCKING_IO
+    if test $gl_cv_have_nonblocking != yes; then
+      REPLACE_STDIO_READ_FUNCS=1
+      AC_LIBOBJ([stdio-read])
+    fi
+  ])
+
+  dnl No need to create extra modules for these functions. Everyone who uses
+  dnl <stdio.h> likely needs them.
+  GNULIB_FPRINTF=1
+  GNULIB_PRINTF=1
+  GNULIB_VFPRINTF=1
+  GNULIB_VPRINTF=1
+  GNULIB_FPUTC=1
+  GNULIB_PUTC=1
+  GNULIB_PUTCHAR=1
+  GNULIB_FPUTS=1
+  GNULIB_PUTS=1
+  GNULIB_FWRITE=1
+  dnl This ifdef is necessary to avoid an error "missing file lib/stdio-write.c"
+  dnl "expected source file, required through AC_LIBSOURCES, not found". It is
+  dnl also an optimization, to avoid performing a configure check whose result
+  dnl is not used. But it does not make the test of GNULIB_STDIO_H_SIGPIPE or
+  dnl GNULIB_SIGPIPE redundant.
+  m4_ifdef([gl_SIGNAL_SIGPIPE], [
+    gl_SIGNAL_SIGPIPE
+    if test $gl_cv_header_signal_h_SIGPIPE != yes; then
+      REPLACE_STDIO_WRITE_FUNCS=1
+      AC_LIBOBJ([stdio-write])
+    fi
+  ])
+  dnl This ifdef is necessary to avoid an error "missing file lib/stdio-write.c"
+  dnl "expected source file, required through AC_LIBSOURCES, not found". It is
+  dnl also an optimization, to avoid performing a configure check whose result
+  dnl is not used. But it does not make the test of GNULIB_STDIO_H_NONBLOCKING
+  dnl or GNULIB_NONBLOCKING redundant.
+  m4_ifdef([gl_NONBLOCKING_IO], [
+    gl_NONBLOCKING_IO
+    if test $gl_cv_have_nonblocking != yes; then
+      REPLACE_STDIO_WRITE_FUNCS=1
+      AC_LIBOBJ([stdio-write])
+    fi
+  ])
+
+  dnl Check for declarations of anything we want to poison if the
+  dnl corresponding gnulib module is not in use, and which is not
+  dnl guaranteed by both C89 and C11.
+  gl_WARN_ON_USE_PREPARE([[#include <stdio.h>
+    ]], [dprintf fpurge fseeko ftello getdelim getline gets pclose popen
+    renameat snprintf tmpfile vdprintf vsnprintf])
+
+  AC_REQUIRE([AC_C_RESTRICT])
+
+  AC_CHECK_DECLS_ONCE([fcloseall])
+  if test $ac_cv_have_decl_fcloseall = no; then
+    HAVE_DECL_FCLOSEALL=0
+  fi
+])
+
+AC_DEFUN([gl_STDIO_MODULE_INDICATOR],
+[
+  dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
+  AC_REQUIRE([gl_STDIO_H_DEFAULTS])
+  gl_MODULE_INDICATOR_SET_VARIABLE([$1])
+  dnl Define it also as a C macro, for the benefit of the unit tests.
+  gl_MODULE_INDICATOR_FOR_TESTS([$1])
+])
+
+AC_DEFUN([gl_STDIO_H_DEFAULTS],
+[
+  GNULIB_DPRINTF=0;              AC_SUBST([GNULIB_DPRINTF])
+  GNULIB_FCLOSE=0;               AC_SUBST([GNULIB_FCLOSE])
+  GNULIB_FDOPEN=0;               AC_SUBST([GNULIB_FDOPEN])
+  GNULIB_FFLUSH=0;               AC_SUBST([GNULIB_FFLUSH])
+  GNULIB_FGETC=0;                AC_SUBST([GNULIB_FGETC])
+  GNULIB_FGETS=0;                AC_SUBST([GNULIB_FGETS])
+  GNULIB_FOPEN=0;                AC_SUBST([GNULIB_FOPEN])
+  GNULIB_FPRINTF=0;              AC_SUBST([GNULIB_FPRINTF])
+  GNULIB_FPRINTF_POSIX=0;        AC_SUBST([GNULIB_FPRINTF_POSIX])
+  GNULIB_FPURGE=0;               AC_SUBST([GNULIB_FPURGE])
+  GNULIB_FPUTC=0;                AC_SUBST([GNULIB_FPUTC])
+  GNULIB_FPUTS=0;                AC_SUBST([GNULIB_FPUTS])
+  GNULIB_FREAD=0;                AC_SUBST([GNULIB_FREAD])
+  GNULIB_FREOPEN=0;              AC_SUBST([GNULIB_FREOPEN])
+  GNULIB_FSCANF=0;               AC_SUBST([GNULIB_FSCANF])
+  GNULIB_FSEEK=0;                AC_SUBST([GNULIB_FSEEK])
+  GNULIB_FSEEKO=0;               AC_SUBST([GNULIB_FSEEKO])
+  GNULIB_FTELL=0;                AC_SUBST([GNULIB_FTELL])
+  GNULIB_FTELLO=0;               AC_SUBST([GNULIB_FTELLO])
+  GNULIB_FWRITE=0;               AC_SUBST([GNULIB_FWRITE])
+  GNULIB_GETC=0;                 AC_SUBST([GNULIB_GETC])
+  GNULIB_GETCHAR=0;              AC_SUBST([GNULIB_GETCHAR])
+  GNULIB_GETDELIM=0;             AC_SUBST([GNULIB_GETDELIM])
+  GNULIB_GETLINE=0;              AC_SUBST([GNULIB_GETLINE])
+  GNULIB_OBSTACK_PRINTF=0;       AC_SUBST([GNULIB_OBSTACK_PRINTF])
+  GNULIB_OBSTACK_PRINTF_POSIX=0; AC_SUBST([GNULIB_OBSTACK_PRINTF_POSIX])
+  GNULIB_PCLOSE=0;               AC_SUBST([GNULIB_PCLOSE])
+  GNULIB_PERROR=0;               AC_SUBST([GNULIB_PERROR])
+  GNULIB_POPEN=0;                AC_SUBST([GNULIB_POPEN])
+  GNULIB_PRINTF=0;               AC_SUBST([GNULIB_PRINTF])
+  GNULIB_PRINTF_POSIX=0;         AC_SUBST([GNULIB_PRINTF_POSIX])
+  GNULIB_PUTC=0;                 AC_SUBST([GNULIB_PUTC])
+  GNULIB_PUTCHAR=0;              AC_SUBST([GNULIB_PUTCHAR])
+  GNULIB_PUTS=0;                 AC_SUBST([GNULIB_PUTS])
+  GNULIB_REMOVE=0;               AC_SUBST([GNULIB_REMOVE])
+  GNULIB_RENAME=0;               AC_SUBST([GNULIB_RENAME])
+  GNULIB_RENAMEAT=0;             AC_SUBST([GNULIB_RENAMEAT])
+  GNULIB_SCANF=0;                AC_SUBST([GNULIB_SCANF])
+  GNULIB_SNPRINTF=0;             AC_SUBST([GNULIB_SNPRINTF])
+  GNULIB_SPRINTF_POSIX=0;        AC_SUBST([GNULIB_SPRINTF_POSIX])
+  GNULIB_STDIO_H_NONBLOCKING=0;  AC_SUBST([GNULIB_STDIO_H_NONBLOCKING])
+  GNULIB_STDIO_H_SIGPIPE=0;      AC_SUBST([GNULIB_STDIO_H_SIGPIPE])
+  GNULIB_TMPFILE=0;              AC_SUBST([GNULIB_TMPFILE])
+  GNULIB_VASPRINTF=0;            AC_SUBST([GNULIB_VASPRINTF])
+  GNULIB_VFSCANF=0;              AC_SUBST([GNULIB_VFSCANF])
+  GNULIB_VSCANF=0;               AC_SUBST([GNULIB_VSCANF])
+  GNULIB_VDPRINTF=0;             AC_SUBST([GNULIB_VDPRINTF])
+  GNULIB_VFPRINTF=0;             AC_SUBST([GNULIB_VFPRINTF])
+  GNULIB_VFPRINTF_POSIX=0;       AC_SUBST([GNULIB_VFPRINTF_POSIX])
+  GNULIB_VPRINTF=0;              AC_SUBST([GNULIB_VPRINTF])
+  GNULIB_VPRINTF_POSIX=0;        AC_SUBST([GNULIB_VPRINTF_POSIX])
+  GNULIB_VSNPRINTF=0;            AC_SUBST([GNULIB_VSNPRINTF])
+  GNULIB_VSPRINTF_POSIX=0;       AC_SUBST([GNULIB_VSPRINTF_POSIX])
+  dnl Support Microsoft deprecated alias function names by default.
+  GNULIB_MDA_FCLOSEALL=1;        AC_SUBST([GNULIB_MDA_FCLOSEALL])
+  GNULIB_MDA_FDOPEN=1;           AC_SUBST([GNULIB_MDA_FDOPEN])
+  GNULIB_MDA_FILENO=1;           AC_SUBST([GNULIB_MDA_FILENO])
+  GNULIB_MDA_GETW=1;             AC_SUBST([GNULIB_MDA_GETW])
+  GNULIB_MDA_PUTW=1;             AC_SUBST([GNULIB_MDA_PUTW])
+  GNULIB_MDA_TEMPNAM=1;          AC_SUBST([GNULIB_MDA_TEMPNAM])
+  dnl Assume proper GNU behavior unless another module says otherwise.
+  HAVE_DECL_FCLOSEALL=1;         AC_SUBST([HAVE_DECL_FCLOSEALL])
+  HAVE_DECL_FPURGE=1;            AC_SUBST([HAVE_DECL_FPURGE])
+  HAVE_DECL_FSEEKO=1;            AC_SUBST([HAVE_DECL_FSEEKO])
+  HAVE_DECL_FTELLO=1;            AC_SUBST([HAVE_DECL_FTELLO])
+  HAVE_DECL_GETDELIM=1;          AC_SUBST([HAVE_DECL_GETDELIM])
+  HAVE_DECL_GETLINE=1;           AC_SUBST([HAVE_DECL_GETLINE])
+  HAVE_DECL_OBSTACK_PRINTF=1;    AC_SUBST([HAVE_DECL_OBSTACK_PRINTF])
+  HAVE_DECL_SNPRINTF=1;          AC_SUBST([HAVE_DECL_SNPRINTF])
+  HAVE_DECL_VSNPRINTF=1;         AC_SUBST([HAVE_DECL_VSNPRINTF])
+  HAVE_DPRINTF=1;                AC_SUBST([HAVE_DPRINTF])
+  HAVE_FSEEKO=1;                 AC_SUBST([HAVE_FSEEKO])
+  HAVE_FTELLO=1;                 AC_SUBST([HAVE_FTELLO])
+  HAVE_PCLOSE=1;                 AC_SUBST([HAVE_PCLOSE])
+  HAVE_POPEN=1;                  AC_SUBST([HAVE_POPEN])
+  HAVE_RENAMEAT=1;               AC_SUBST([HAVE_RENAMEAT])
+  HAVE_VASPRINTF=1;              AC_SUBST([HAVE_VASPRINTF])
+  HAVE_VDPRINTF=1;               AC_SUBST([HAVE_VDPRINTF])
+  REPLACE_DPRINTF=0;             AC_SUBST([REPLACE_DPRINTF])
+  REPLACE_FCLOSE=0;              AC_SUBST([REPLACE_FCLOSE])
+  REPLACE_FDOPEN=0;              AC_SUBST([REPLACE_FDOPEN])
+  REPLACE_FFLUSH=0;              AC_SUBST([REPLACE_FFLUSH])
+  REPLACE_FOPEN=0;               AC_SUBST([REPLACE_FOPEN])
+  REPLACE_FPRINTF=0;             AC_SUBST([REPLACE_FPRINTF])
+  REPLACE_FPURGE=0;              AC_SUBST([REPLACE_FPURGE])
+  REPLACE_FREOPEN=0;             AC_SUBST([REPLACE_FREOPEN])
+  REPLACE_FSEEK=0;               AC_SUBST([REPLACE_FSEEK])
+  REPLACE_FSEEKO=0;              AC_SUBST([REPLACE_FSEEKO])
+  REPLACE_FTELL=0;               AC_SUBST([REPLACE_FTELL])
+  REPLACE_FTELLO=0;              AC_SUBST([REPLACE_FTELLO])
+  REPLACE_GETDELIM=0;            AC_SUBST([REPLACE_GETDELIM])
+  REPLACE_GETLINE=0;             AC_SUBST([REPLACE_GETLINE])
+  REPLACE_OBSTACK_PRINTF=0;      AC_SUBST([REPLACE_OBSTACK_PRINTF])
+  REPLACE_PERROR=0;              AC_SUBST([REPLACE_PERROR])
+  REPLACE_POPEN=0;               AC_SUBST([REPLACE_POPEN])
+  REPLACE_PRINTF=0;              AC_SUBST([REPLACE_PRINTF])
+  REPLACE_REMOVE=0;              AC_SUBST([REPLACE_REMOVE])
+  REPLACE_RENAME=0;              AC_SUBST([REPLACE_RENAME])
+  REPLACE_RENAMEAT=0;            AC_SUBST([REPLACE_RENAMEAT])
+  REPLACE_SNPRINTF=0;            AC_SUBST([REPLACE_SNPRINTF])
+  REPLACE_SPRINTF=0;             AC_SUBST([REPLACE_SPRINTF])
+  REPLACE_STDIO_READ_FUNCS=0;    AC_SUBST([REPLACE_STDIO_READ_FUNCS])
+  REPLACE_STDIO_WRITE_FUNCS=0;   AC_SUBST([REPLACE_STDIO_WRITE_FUNCS])
+  REPLACE_TMPFILE=0;             AC_SUBST([REPLACE_TMPFILE])
+  REPLACE_VASPRINTF=0;           AC_SUBST([REPLACE_VASPRINTF])
+  REPLACE_VDPRINTF=0;            AC_SUBST([REPLACE_VDPRINTF])
+  REPLACE_VFPRINTF=0;            AC_SUBST([REPLACE_VFPRINTF])
+  REPLACE_VPRINTF=0;             AC_SUBST([REPLACE_VPRINTF])
+  REPLACE_VSNPRINTF=0;           AC_SUBST([REPLACE_VSNPRINTF])
+  REPLACE_VSPRINTF=0;            AC_SUBST([REPLACE_VSPRINTF])
+])
diff --git a/m4/stdlib_h.m4 b/m4/stdlib_h.m4
new file mode 100644
index 0000000..49d4eba
--- /dev/null
+++ b/m4/stdlib_h.m4
@@ -0,0 +1,170 @@
+# stdlib_h.m4 serial 55
+dnl Copyright (C) 2007-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_STDLIB_H],
+[
+  AC_REQUIRE([gl_STDLIB_H_DEFAULTS])
+  gl_NEXT_HEADERS([stdlib.h])
+
+  dnl Check for declarations of anything we want to poison if the
+  dnl corresponding gnulib module is not in use, and which is not
+  dnl guaranteed by C89.
+  gl_WARN_ON_USE_PREPARE([[#include <stdlib.h>
+#if HAVE_SYS_LOADAVG_H
+/* OpenIndiana has a bug: <sys/time.h> must be included before
+   <sys/loadavg.h>.  */
+# include <sys/time.h>
+# include <sys/loadavg.h>
+#endif
+#if HAVE_RANDOM_H
+# include <random.h>
+#endif
+    ]], [_Exit aligned_alloc atoll canonicalize_file_name free
+    getloadavg getsubopt grantpt
+    initstate initstate_r mbtowc mkdtemp mkostemp mkostemps mkstemp mkstemps
+    posix_memalign posix_openpt ptsname ptsname_r qsort_r
+    random random_r reallocarray realpath rpmatch secure_getenv setenv
+    setstate setstate_r srandom srandom_r
+    strtod strtold strtoll strtoull unlockpt unsetenv])
+
+  AC_REQUIRE([AC_C_RESTRICT])
+
+  AC_CHECK_DECLS_ONCE([ecvt])
+  if test $ac_cv_have_decl_ecvt = no; then
+    HAVE_DECL_ECVT=0
+  fi
+  AC_CHECK_DECLS_ONCE([fcvt])
+  if test $ac_cv_have_decl_fcvt = no; then
+    HAVE_DECL_FCVT=0
+  fi
+  AC_CHECK_DECLS_ONCE([gcvt])
+  if test $ac_cv_have_decl_gcvt = no; then
+    HAVE_DECL_GCVT=0
+  fi
+])
+
+AC_DEFUN([gl_STDLIB_MODULE_INDICATOR],
+[
+  dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
+  AC_REQUIRE([gl_STDLIB_H_DEFAULTS])
+  gl_MODULE_INDICATOR_SET_VARIABLE([$1])
+  dnl Define it also as a C macro, for the benefit of the unit tests.
+  gl_MODULE_INDICATOR_FOR_TESTS([$1])
+])
+
+AC_DEFUN([gl_STDLIB_H_DEFAULTS],
+[
+  GNULIB__EXIT=0;         AC_SUBST([GNULIB__EXIT])
+  GNULIB_ALIGNED_ALLOC=0; AC_SUBST([GNULIB_ALIGNED_ALLOC])
+  GNULIB_ATOLL=0;         AC_SUBST([GNULIB_ATOLL])
+  GNULIB_CALLOC_POSIX=0;  AC_SUBST([GNULIB_CALLOC_POSIX])
+  GNULIB_CANONICALIZE_FILE_NAME=0;  AC_SUBST([GNULIB_CANONICALIZE_FILE_NAME])
+  GNULIB_FREE_POSIX=0;    AC_SUBST([GNULIB_FREE_POSIX])
+  GNULIB_GETLOADAVG=0;    AC_SUBST([GNULIB_GETLOADAVG])
+  GNULIB_GETSUBOPT=0;     AC_SUBST([GNULIB_GETSUBOPT])
+  GNULIB_GRANTPT=0;       AC_SUBST([GNULIB_GRANTPT])
+  GNULIB_MALLOC_POSIX=0;  AC_SUBST([GNULIB_MALLOC_POSIX])
+  GNULIB_MBTOWC=0;        AC_SUBST([GNULIB_MBTOWC])
+  GNULIB_MKDTEMP=0;       AC_SUBST([GNULIB_MKDTEMP])
+  GNULIB_MKOSTEMP=0;      AC_SUBST([GNULIB_MKOSTEMP])
+  GNULIB_MKOSTEMPS=0;     AC_SUBST([GNULIB_MKOSTEMPS])
+  GNULIB_MKSTEMP=0;       AC_SUBST([GNULIB_MKSTEMP])
+  GNULIB_MKSTEMPS=0;      AC_SUBST([GNULIB_MKSTEMPS])
+  GNULIB_POSIX_MEMALIGN=0;AC_SUBST([GNULIB_POSIX_MEMALIGN])
+  GNULIB_POSIX_OPENPT=0;  AC_SUBST([GNULIB_POSIX_OPENPT])
+  GNULIB_PTSNAME=0;       AC_SUBST([GNULIB_PTSNAME])
+  GNULIB_PTSNAME_R=0;     AC_SUBST([GNULIB_PTSNAME_R])
+  GNULIB_PUTENV=0;        AC_SUBST([GNULIB_PUTENV])
+  GNULIB_QSORT_R=0;       AC_SUBST([GNULIB_QSORT_R])
+  GNULIB_RANDOM=0;        AC_SUBST([GNULIB_RANDOM])
+  GNULIB_RANDOM_R=0;      AC_SUBST([GNULIB_RANDOM_R])
+  GNULIB_REALLOCARRAY=0;  AC_SUBST([GNULIB_REALLOCARRAY])
+  GNULIB_REALLOC_POSIX=0; AC_SUBST([GNULIB_REALLOC_POSIX])
+  GNULIB_REALPATH=0;      AC_SUBST([GNULIB_REALPATH])
+  GNULIB_RPMATCH=0;       AC_SUBST([GNULIB_RPMATCH])
+  GNULIB_SECURE_GETENV=0; AC_SUBST([GNULIB_SECURE_GETENV])
+  GNULIB_SETENV=0;        AC_SUBST([GNULIB_SETENV])
+  GNULIB_STRTOD=0;        AC_SUBST([GNULIB_STRTOD])
+  GNULIB_STRTOLD=0;       AC_SUBST([GNULIB_STRTOLD])
+  GNULIB_STRTOLL=0;       AC_SUBST([GNULIB_STRTOLL])
+  GNULIB_STRTOULL=0;      AC_SUBST([GNULIB_STRTOULL])
+  GNULIB_SYSTEM_POSIX=0;  AC_SUBST([GNULIB_SYSTEM_POSIX])
+  GNULIB_UNLOCKPT=0;      AC_SUBST([GNULIB_UNLOCKPT])
+  GNULIB_UNSETENV=0;      AC_SUBST([GNULIB_UNSETENV])
+  GNULIB_WCTOMB=0;        AC_SUBST([GNULIB_WCTOMB])
+  dnl Support Microsoft deprecated alias function names by default.
+  GNULIB_MDA_ECVT=1;      AC_SUBST([GNULIB_MDA_ECVT])
+  GNULIB_MDA_FCVT=1;      AC_SUBST([GNULIB_MDA_FCVT])
+  GNULIB_MDA_GCVT=1;      AC_SUBST([GNULIB_MDA_GCVT])
+  GNULIB_MDA_MKTEMP=1;    AC_SUBST([GNULIB_MDA_MKTEMP])
+  GNULIB_MDA_PUTENV=1;    AC_SUBST([GNULIB_MDA_PUTENV])
+  dnl Assume proper GNU behavior unless another module says otherwise.
+  HAVE__EXIT=1;              AC_SUBST([HAVE__EXIT])
+  HAVE_ALIGNED_ALLOC=1;      AC_SUBST([HAVE_ALIGNED_ALLOC])
+  HAVE_ATOLL=1;              AC_SUBST([HAVE_ATOLL])
+  HAVE_CANONICALIZE_FILE_NAME=1;  AC_SUBST([HAVE_CANONICALIZE_FILE_NAME])
+  HAVE_DECL_ECVT=1;          AC_SUBST([HAVE_DECL_ECVT])
+  HAVE_DECL_FCVT=1;          AC_SUBST([HAVE_DECL_FCVT])
+  HAVE_DECL_GCVT=1;          AC_SUBST([HAVE_DECL_GCVT])
+  HAVE_DECL_GETLOADAVG=1;    AC_SUBST([HAVE_DECL_GETLOADAVG])
+  HAVE_GETSUBOPT=1;          AC_SUBST([HAVE_GETSUBOPT])
+  HAVE_GRANTPT=1;            AC_SUBST([HAVE_GRANTPT])
+  HAVE_INITSTATE=1;          AC_SUBST([HAVE_INITSTATE])
+  HAVE_DECL_INITSTATE=1;     AC_SUBST([HAVE_DECL_INITSTATE])
+  HAVE_MBTOWC=1;             AC_SUBST([HAVE_MBTOWC])
+  HAVE_MKDTEMP=1;            AC_SUBST([HAVE_MKDTEMP])
+  HAVE_MKOSTEMP=1;           AC_SUBST([HAVE_MKOSTEMP])
+  HAVE_MKOSTEMPS=1;          AC_SUBST([HAVE_MKOSTEMPS])
+  HAVE_MKSTEMP=1;            AC_SUBST([HAVE_MKSTEMP])
+  HAVE_MKSTEMPS=1;           AC_SUBST([HAVE_MKSTEMPS])
+  HAVE_POSIX_MEMALIGN=1;     AC_SUBST([HAVE_POSIX_MEMALIGN])
+  HAVE_POSIX_OPENPT=1;       AC_SUBST([HAVE_POSIX_OPENPT])
+  HAVE_PTSNAME=1;            AC_SUBST([HAVE_PTSNAME])
+  HAVE_PTSNAME_R=1;          AC_SUBST([HAVE_PTSNAME_R])
+  HAVE_QSORT_R=1;            AC_SUBST([HAVE_QSORT_R])
+  HAVE_RANDOM=1;             AC_SUBST([HAVE_RANDOM])
+  HAVE_RANDOM_H=1;           AC_SUBST([HAVE_RANDOM_H])
+  HAVE_RANDOM_R=1;           AC_SUBST([HAVE_RANDOM_R])
+  HAVE_REALLOCARRAY=1;       AC_SUBST([HAVE_REALLOCARRAY])
+  HAVE_REALPATH=1;           AC_SUBST([HAVE_REALPATH])
+  HAVE_RPMATCH=1;            AC_SUBST([HAVE_RPMATCH])
+  HAVE_SECURE_GETENV=1;      AC_SUBST([HAVE_SECURE_GETENV])
+  HAVE_SETENV=1;             AC_SUBST([HAVE_SETENV])
+  HAVE_DECL_SETENV=1;        AC_SUBST([HAVE_DECL_SETENV])
+  HAVE_SETSTATE=1;           AC_SUBST([HAVE_SETSTATE])
+  HAVE_DECL_SETSTATE=1;      AC_SUBST([HAVE_DECL_SETSTATE])
+  HAVE_STRTOD=1;             AC_SUBST([HAVE_STRTOD])
+  HAVE_STRTOLD=1;            AC_SUBST([HAVE_STRTOLD])
+  HAVE_STRTOLL=1;            AC_SUBST([HAVE_STRTOLL])
+  HAVE_STRTOULL=1;           AC_SUBST([HAVE_STRTOULL])
+  HAVE_STRUCT_RANDOM_DATA=1; AC_SUBST([HAVE_STRUCT_RANDOM_DATA])
+  HAVE_SYS_LOADAVG_H=0;      AC_SUBST([HAVE_SYS_LOADAVG_H])
+  HAVE_UNLOCKPT=1;           AC_SUBST([HAVE_UNLOCKPT])
+  HAVE_DECL_UNSETENV=1;      AC_SUBST([HAVE_DECL_UNSETENV])
+  REPLACE_ALIGNED_ALLOC=0;   AC_SUBST([REPLACE_ALIGNED_ALLOC])
+  REPLACE_CALLOC=0;          AC_SUBST([REPLACE_CALLOC])
+  REPLACE_CANONICALIZE_FILE_NAME=0;  AC_SUBST([REPLACE_CANONICALIZE_FILE_NAME])
+  REPLACE_FREE=0;            AC_SUBST([REPLACE_FREE])
+  REPLACE_INITSTATE=0;       AC_SUBST([REPLACE_INITSTATE])
+  REPLACE_MALLOC=0;          AC_SUBST([REPLACE_MALLOC])
+  REPLACE_MBTOWC=0;          AC_SUBST([REPLACE_MBTOWC])
+  REPLACE_MKSTEMP=0;         AC_SUBST([REPLACE_MKSTEMP])
+  REPLACE_POSIX_MEMALIGN=0;  AC_SUBST([REPLACE_POSIX_MEMALIGN])
+  REPLACE_PTSNAME=0;         AC_SUBST([REPLACE_PTSNAME])
+  REPLACE_PTSNAME_R=0;       AC_SUBST([REPLACE_PTSNAME_R])
+  REPLACE_PUTENV=0;          AC_SUBST([REPLACE_PUTENV])
+  REPLACE_QSORT_R=0;         AC_SUBST([REPLACE_QSORT_R])
+  REPLACE_RANDOM=0;          AC_SUBST([REPLACE_RANDOM])
+  REPLACE_RANDOM_R=0;        AC_SUBST([REPLACE_RANDOM_R])
+  REPLACE_REALLOC=0;         AC_SUBST([REPLACE_REALLOC])
+  REPLACE_REALPATH=0;        AC_SUBST([REPLACE_REALPATH])
+  REPLACE_SETENV=0;          AC_SUBST([REPLACE_SETENV])
+  REPLACE_SETSTATE=0;        AC_SUBST([REPLACE_SETSTATE])
+  REPLACE_STRTOD=0;          AC_SUBST([REPLACE_STRTOD])
+  REPLACE_STRTOLD=0;         AC_SUBST([REPLACE_STRTOLD])
+  REPLACE_UNSETENV=0;        AC_SUBST([REPLACE_UNSETENV])
+  REPLACE_WCTOMB=0;          AC_SUBST([REPLACE_WCTOMB])
+])
diff --git a/m4/stpcpy.m4 b/m4/stpcpy.m4
new file mode 100644
index 0000000..0f0fa9e
--- /dev/null
+++ b/m4/stpcpy.m4
@@ -0,0 +1,25 @@
+# stpcpy.m4 serial 8
+dnl Copyright (C) 2002, 2007, 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_STPCPY],
+[
+  dnl Persuade glibc <string.h> to declare stpcpy().
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
+
+  dnl The stpcpy() declaration in lib/string.in.h uses 'restrict'.
+  AC_REQUIRE([AC_C_RESTRICT])
+
+  AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS])
+  AC_CHECK_FUNCS([stpcpy])
+  if test $ac_cv_func_stpcpy = no; then
+    HAVE_STPCPY=0
+  fi
+])
+
+# Prerequisites of lib/stpcpy.c.
+AC_DEFUN([gl_PREREQ_STPCPY], [
+  :
+])
diff --git a/m4/strcase.m4 b/m4/strcase.m4
new file mode 100644
index 0000000..21d80c8
--- /dev/null
+++ b/m4/strcase.m4
@@ -0,0 +1,45 @@
+# strcase.m4 serial 11
+dnl Copyright (C) 2002, 2005-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_STRCASE],
+[
+  gl_FUNC_STRCASECMP
+  gl_FUNC_STRNCASECMP
+])
+
+AC_DEFUN([gl_FUNC_STRCASECMP],
+[
+  AC_REQUIRE([gl_HEADER_STRINGS_H_DEFAULTS])
+  AC_CHECK_FUNCS([strcasecmp])
+  if test $ac_cv_func_strcasecmp = no; then
+    HAVE_STRCASECMP=0
+  fi
+])
+
+AC_DEFUN([gl_FUNC_STRNCASECMP],
+[
+  AC_REQUIRE([gl_HEADER_STRINGS_H_DEFAULTS])
+  AC_CHECK_FUNCS([strncasecmp])
+  if test $ac_cv_func_strncasecmp = yes; then
+    HAVE_STRNCASECMP=1
+  else
+    HAVE_STRNCASECMP=0
+  fi
+  AC_CHECK_DECLS([strncasecmp])
+  if test $ac_cv_have_decl_strncasecmp = no; then
+    HAVE_DECL_STRNCASECMP=0
+  fi
+])
+
+# Prerequisites of lib/strcasecmp.c.
+AC_DEFUN([gl_PREREQ_STRCASECMP], [
+  :
+])
+
+# Prerequisites of lib/strncasecmp.c.
+AC_DEFUN([gl_PREREQ_STRNCASECMP], [
+  :
+])
diff --git a/m4/strchrnul.m4 b/m4/strchrnul.m4
new file mode 100644
index 0000000..a18f093
--- /dev/null
+++ b/m4/strchrnul.m4
@@ -0,0 +1,50 @@
+# strchrnul.m4 serial 9
+dnl Copyright (C) 2003, 2007, 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_STRCHRNUL],
+[
+  dnl Persuade glibc <string.h> to declare strchrnul().
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
+
+  AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS])
+  AC_CHECK_FUNCS([strchrnul])
+  if test $ac_cv_func_strchrnul = no; then
+    HAVE_STRCHRNUL=0
+  else
+    AC_CACHE_CHECK([whether strchrnul works],
+      [gl_cv_func_strchrnul_works],
+      [AC_RUN_IFELSE([AC_LANG_PROGRAM([[
+#include <string.h> /* for strchrnul */
+]], [[const char *buf = "a";
+      return strchrnul (buf, 'b') != buf + 1;
+    ]])],
+        [gl_cv_func_strchrnul_works=yes],
+        [gl_cv_func_strchrnul_works=no],
+        [dnl Cygwin 1.7.9 introduced strchrnul, but it was broken until 1.7.10
+         AC_EGREP_CPP([Lucky user],
+           [
+#if defined __CYGWIN__
+ #include <cygwin/version.h>
+ #if CYGWIN_VERSION_DLL_COMBINED > CYGWIN_VERSION_DLL_MAKE_COMBINED (1007, 9)
+  Lucky user
+ #endif
+#else
+  Lucky user
+#endif
+           ],
+           [gl_cv_func_strchrnul_works="guessing yes"],
+           [gl_cv_func_strchrnul_works="guessing no"])
+        ])
+      ])
+    case "$gl_cv_func_strchrnul_works" in
+      *yes) ;;
+      *) REPLACE_STRCHRNUL=1 ;;
+    esac
+  fi
+])
+
+# Prerequisites of lib/strchrnul.c.
+AC_DEFUN([gl_PREREQ_STRCHRNUL], [:])
diff --git a/m4/strdup.m4 b/m4/strdup.m4
new file mode 100644
index 0000000..6340209
--- /dev/null
+++ b/m4/strdup.m4
@@ -0,0 +1,32 @@
+# strdup.m4 serial 14
+
+dnl Copyright (C) 2002-2020 Free Software Foundation, Inc.
+
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_STRDUP],
+[
+  AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS])
+  AC_CHECK_DECLS_ONCE([strdup])
+  if test $ac_cv_have_decl_strdup = no; then
+    HAVE_DECL_STRDUP=0
+  fi
+])
+
+AC_DEFUN([gl_FUNC_STRDUP_POSIX],
+[
+  AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS])
+  AC_REQUIRE([gl_CHECK_MALLOC_POSIX])
+  if test $gl_cv_func_malloc_posix != yes; then
+    REPLACE_STRDUP=1
+  fi
+  AC_CHECK_DECLS_ONCE([strdup])
+  if test $ac_cv_have_decl_strdup = no; then
+    HAVE_DECL_STRDUP=0
+  fi
+])
+
+# Prerequisites of lib/strdup.c.
+AC_DEFUN([gl_PREREQ_STRDUP], [:])
diff --git a/m4/strerror.m4 b/m4/strerror.m4
new file mode 100644
index 0000000..fd84ce8
--- /dev/null
+++ b/m4/strerror.m4
@@ -0,0 +1,102 @@
+# strerror.m4 serial 21
+dnl Copyright (C) 2002, 2007-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_STRERROR],
+[
+  AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS])
+  AC_REQUIRE([gl_HEADER_ERRNO_H])
+  AC_REQUIRE([gl_FUNC_STRERROR_0])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  m4_ifdef([gl_FUNC_STRERROR_R_WORKS], [
+    AC_REQUIRE([gl_FUNC_STRERROR_R_WORKS])
+  ])
+  if test "$ERRNO_H:$REPLACE_STRERROR_0" = :0; then
+    AC_CACHE_CHECK([for working strerror function],
+     [gl_cv_func_working_strerror],
+     [AC_RUN_IFELSE(
+        [AC_LANG_PROGRAM(
+           [[#include <string.h>
+           ]],
+           [[if (!*strerror (-2)) return 1;]])],
+        [gl_cv_func_working_strerror=yes],
+        [gl_cv_func_working_strerror=no],
+        [case "$host_os" in
+                          # Guess yes on glibc systems.
+           *-gnu* | gnu*) gl_cv_func_working_strerror="guessing yes" ;;
+                          # Guess yes on musl systems.
+           *-musl*)       gl_cv_func_working_strerror="guessing yes" ;;
+                          # If we don't know, obey --enable-cross-guesses.
+           *)             gl_cv_func_working_strerror="$gl_cross_guess_normal" ;;
+         esac
+        ])
+    ])
+    case "$gl_cv_func_working_strerror" in
+      *yes) ;;
+      *)
+        dnl The system's strerror() fails to return a string for out-of-range
+        dnl integers. Replace it.
+        REPLACE_STRERROR=1
+        ;;
+    esac
+    m4_ifdef([gl_FUNC_STRERROR_R_WORKS], [
+      dnl If the system's strerror_r or __xpg_strerror_r clobbers strerror's
+      dnl buffer, we must replace strerror.
+      case "$gl_cv_func_strerror_r_works" in
+        *no) REPLACE_STRERROR=1 ;;
+      esac
+    ])
+  else
+    dnl The system's strerror() cannot know about the new errno values we add
+    dnl to <errno.h>, or any fix for strerror(0). Replace it.
+    REPLACE_STRERROR=1
+  fi
+])
+
+dnl Detect if strerror(0) passes (that is, does not set errno, and does not
+dnl return a string that matches strerror(-1)).
+AC_DEFUN([gl_FUNC_STRERROR_0],
+[
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  REPLACE_STRERROR_0=0
+  AC_CACHE_CHECK([whether strerror(0) succeeds],
+   [gl_cv_func_strerror_0_works],
+   [AC_RUN_IFELSE(
+      [AC_LANG_PROGRAM(
+         [[#include <string.h>
+           #include <errno.h>
+         ]],
+         [[int result = 0;
+           char *str;
+           errno = 0;
+           str = strerror (0);
+           if (!*str) result |= 1;
+           if (errno) result |= 2;
+           if (strstr (str, "nknown") || strstr (str, "ndefined"))
+             result |= 4;
+           return result;]])],
+      [gl_cv_func_strerror_0_works=yes],
+      [gl_cv_func_strerror_0_works=no],
+      [case "$host_os" in
+                        # Guess yes on glibc systems.
+         *-gnu* | gnu*) gl_cv_func_strerror_0_works="guessing yes" ;;
+                        # Guess yes on musl systems.
+         *-musl*)       gl_cv_func_strerror_0_works="guessing yes" ;;
+                        # Guess yes on native Windows.
+         mingw*)        gl_cv_func_strerror_0_works="guessing yes" ;;
+                        # If we don't know, obey --enable-cross-guesses.
+         *)             gl_cv_func_strerror_0_works="$gl_cross_guess_normal" ;;
+       esac
+      ])
+  ])
+  case "$gl_cv_func_strerror_0_works" in
+    *yes) ;;
+    *)
+      REPLACE_STRERROR_0=1
+      AC_DEFINE([REPLACE_STRERROR_0], [1], [Define to 1 if strerror(0)
+        does not return a message implying success.])
+      ;;
+  esac
+])
diff --git a/m4/strerror_r.m4 b/m4/strerror_r.m4
new file mode 100644
index 0000000..d431f23
--- /dev/null
+++ b/m4/strerror_r.m4
@@ -0,0 +1,173 @@
+# strerror_r.m4 serial 20
+dnl Copyright (C) 2002, 2007-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_STRERROR_R],
+[
+  AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS])
+  AC_REQUIRE([gl_FUNC_STRERROR_R_WORKS])
+
+  dnl Persuade Solaris <string.h> to declare strerror_r().
+  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+
+  dnl Some systems don't declare strerror_r() if _THREAD_SAFE and _REENTRANT
+  dnl are not defined.
+  AC_CHECK_DECLS_ONCE([strerror_r])
+  if test $ac_cv_have_decl_strerror_r = no; then
+    HAVE_DECL_STRERROR_R=0
+  fi
+
+  if test $ac_cv_func_strerror_r = yes; then
+    if test "$ERRNO_H:$REPLACE_STRERROR_0" = :0; then
+      if test $gl_cv_func_strerror_r_posix_signature = yes; then
+        case "$gl_cv_func_strerror_r_works" in
+          dnl The system's strerror_r has bugs.  Replace it.
+          *no) REPLACE_STRERROR_R=1 ;;
+        esac
+      else
+        dnl The system's strerror_r() has a wrong signature. Replace it.
+        REPLACE_STRERROR_R=1
+      fi
+    else
+      dnl The system's strerror_r() cannot know about the new errno values we
+      dnl add to <errno.h>, or any fix for strerror(0). Replace it.
+      REPLACE_STRERROR_R=1
+    fi
+  fi
+])
+
+# Prerequisites of lib/strerror_r.c.
+AC_DEFUN([gl_PREREQ_STRERROR_R], [
+  dnl glibc >= 2.3.4 and cygwin 1.7.9 have a function __xpg_strerror_r.
+  AC_CHECK_FUNCS_ONCE([__xpg_strerror_r])
+  AC_CHECK_FUNCS_ONCE([catgets])
+  AC_CHECK_FUNCS_ONCE([snprintf])
+])
+
+# Detect if strerror_r works, but without affecting whether a replacement
+# strerror_r will be used.
+AC_DEFUN([gl_FUNC_STRERROR_R_WORKS],
+[
+  AC_REQUIRE([gl_HEADER_ERRNO_H])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_REQUIRE([gl_FUNC_STRERROR_0])
+
+  AC_CHECK_FUNCS_ONCE([strerror_r])
+  if test $ac_cv_func_strerror_r = yes; then
+    if test "$ERRNO_H:$REPLACE_STRERROR_0" = :0; then
+      dnl The POSIX prototype is:  int strerror_r (int, char *, size_t);
+      dnl glibc, Cygwin:           char *strerror_r (int, char *, size_t);
+      dnl AIX 5.1, OSF/1 5.1:      int strerror_r (int, char *, int);
+      AC_CACHE_CHECK([for strerror_r with POSIX signature],
+        [gl_cv_func_strerror_r_posix_signature],
+        [AC_COMPILE_IFELSE(
+           [AC_LANG_PROGRAM(
+              [[#include <string.h>
+                int strerror_r (int, char *, size_t);
+              ]],
+              [])],
+           [gl_cv_func_strerror_r_posix_signature=yes],
+           [gl_cv_func_strerror_r_posix_signature=no])
+        ])
+      if test $gl_cv_func_strerror_r_posix_signature = yes; then
+        dnl AIX 6.1 strerror_r fails by returning -1, not an error number.
+        dnl HP-UX 11.31 strerror_r always fails when the buffer length argument
+        dnl is less than 80.
+        dnl FreeBSD 8.s strerror_r claims failure on 0
+        dnl Mac OS X 10.5 strerror_r treats 0 like -1
+        dnl Solaris 10 strerror_r corrupts errno on failure
+        AC_CACHE_CHECK([whether strerror_r works],
+          [gl_cv_func_strerror_r_works],
+          [AC_RUN_IFELSE(
+             [AC_LANG_PROGRAM(
+                [[#include <errno.h>
+                  #include <string.h>
+                ]],
+                [[int result = 0;
+                  char buf[79];
+                  if (strerror_r (EACCES, buf, 0) < 0)
+                    result |= 1;
+                  errno = 0;
+                  if (strerror_r (EACCES, buf, sizeof buf) != 0)
+                    result |= 2;
+                  strcpy (buf, "Unknown");
+                  if (strerror_r (0, buf, sizeof buf) != 0)
+                    result |= 4;
+                  if (errno)
+                    result |= 8;
+                  if (strstr (buf, "nknown") || strstr (buf, "ndefined"))
+                    result |= 0x10;
+                  errno = 0;
+                  *buf = 0;
+                  if (strerror_r (-3, buf, sizeof buf) < 0)
+                    result |= 0x20;
+                  if (errno)
+                    result |= 0x40;
+                  if (!*buf)
+                    result |= 0x80;
+                  return result;
+                ]])],
+             [gl_cv_func_strerror_r_works=yes],
+             [gl_cv_func_strerror_r_works=no],
+             [
+changequote(,)dnl
+              case "$host_os" in
+                       # Guess no on AIX.
+                aix*)  gl_cv_func_strerror_r_works="guessing no";;
+                       # Guess no on HP-UX.
+                hpux*) gl_cv_func_strerror_r_works="guessing no";;
+                       # Guess no on BSD variants.
+                *bsd*)  gl_cv_func_strerror_r_works="guessing no";;
+                       # Guess yes otherwise.
+                *)     gl_cv_func_strerror_r_works="guessing yes";;
+              esac
+changequote([,])dnl
+             ])
+          ])
+      else
+        dnl The system's strerror() has a wrong signature.
+        dnl glibc >= 2.3.4 and cygwin 1.7.9 have a function __xpg_strerror_r.
+        AC_CHECK_FUNCS_ONCE([__xpg_strerror_r])
+        dnl In glibc < 2.14, __xpg_strerror_r does not populate buf on failure.
+        dnl In cygwin < 1.7.10, __xpg_strerror_r clobbers strerror's buffer.
+        if test $ac_cv_func___xpg_strerror_r = yes; then
+          AC_CACHE_CHECK([whether __xpg_strerror_r works],
+            [gl_cv_func_strerror_r_works],
+            [AC_RUN_IFELSE(
+               [AC_LANG_PROGRAM(
+                  [[#include <errno.h>
+                    #include <string.h>
+                    extern
+                    #ifdef __cplusplus
+                    "C"
+                    #endif
+                    int __xpg_strerror_r(int, char *, size_t);
+                  ]],
+                  [[int result = 0;
+                    char buf[256] = "^";
+                    char copy[256];
+                    char *str = strerror (-1);
+                    strcpy (copy, str);
+                    if (__xpg_strerror_r (-2, buf, 1) == 0)
+                      result |= 1;
+                    if (*buf)
+                      result |= 2;
+                    __xpg_strerror_r (-2, buf, 256);
+                    if (strcmp (str, copy))
+                      result |= 4;
+                    return result;
+                  ]])],
+               [gl_cv_func_strerror_r_works=yes],
+               [gl_cv_func_strerror_r_works=no],
+               [dnl Guess no on all platforms that have __xpg_strerror_r,
+                dnl at least until fixed glibc and cygwin are more common.
+                gl_cv_func_strerror_r_works="$gl_cross_guess_normal"
+               ])
+            ])
+        fi
+      fi
+    fi
+  fi
+])
diff --git a/m4/string_h.m4 b/m4/string_h.m4
new file mode 100644
index 0000000..3d41c63
--- /dev/null
+++ b/m4/string_h.m4
@@ -0,0 +1,132 @@
+# Configure a GNU-like replacement for <string.h>.
+
+# Copyright (C) 2007-2020 Free Software Foundation, Inc.
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+# serial 28
+
+# Written by Paul Eggert.
+
+AC_DEFUN([gl_HEADER_STRING_H],
+[
+  dnl Use AC_REQUIRE here, so that the default behavior below is expanded
+  dnl once only, before all statements that occur in other macros.
+  AC_REQUIRE([gl_HEADER_STRING_H_BODY])
+])
+
+AC_DEFUN([gl_HEADER_STRING_H_BODY],
+[
+  AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS])
+  gl_NEXT_HEADERS([string.h])
+
+  dnl Check for declarations of anything we want to poison if the
+  dnl corresponding gnulib module is not in use, and which is not
+  dnl guaranteed by C89.
+  gl_WARN_ON_USE_PREPARE([[#include <string.h>
+    ]],
+    [ffsl ffsll memmem mempcpy memrchr rawmemchr stpcpy stpncpy strchrnul
+     strdup strncat strndup strnlen strpbrk strsep strcasestr strtok_r
+     strerror_r strerrorname_np sigabbrev_np sigdescr_np strsignal strverscmp])
+
+  AC_REQUIRE([AC_C_RESTRICT])
+])
+
+AC_DEFUN([gl_STRING_MODULE_INDICATOR],
+[
+  dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
+  AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS])
+  gl_MODULE_INDICATOR_SET_VARIABLE([$1])
+  dnl Define it also as a C macro, for the benefit of the unit tests.
+  gl_MODULE_INDICATOR_FOR_TESTS([$1])
+])
+
+AC_DEFUN([gl_HEADER_STRING_H_DEFAULTS],
+[
+  GNULIB_EXPLICIT_BZERO=0;   AC_SUBST([GNULIB_EXPLICIT_BZERO])
+  GNULIB_FFSL=0;             AC_SUBST([GNULIB_FFSL])
+  GNULIB_FFSLL=0;            AC_SUBST([GNULIB_FFSLL])
+  GNULIB_MEMCHR=0;           AC_SUBST([GNULIB_MEMCHR])
+  GNULIB_MEMMEM=0;           AC_SUBST([GNULIB_MEMMEM])
+  GNULIB_MEMPCPY=0;          AC_SUBST([GNULIB_MEMPCPY])
+  GNULIB_MEMRCHR=0;          AC_SUBST([GNULIB_MEMRCHR])
+  GNULIB_RAWMEMCHR=0;        AC_SUBST([GNULIB_RAWMEMCHR])
+  GNULIB_STPCPY=0;           AC_SUBST([GNULIB_STPCPY])
+  GNULIB_STPNCPY=0;          AC_SUBST([GNULIB_STPNCPY])
+  GNULIB_STRCHRNUL=0;        AC_SUBST([GNULIB_STRCHRNUL])
+  GNULIB_STRDUP=0;           AC_SUBST([GNULIB_STRDUP])
+  GNULIB_STRNCAT=0;          AC_SUBST([GNULIB_STRNCAT])
+  GNULIB_STRNDUP=0;          AC_SUBST([GNULIB_STRNDUP])
+  GNULIB_STRNLEN=0;          AC_SUBST([GNULIB_STRNLEN])
+  GNULIB_STRPBRK=0;          AC_SUBST([GNULIB_STRPBRK])
+  GNULIB_STRSEP=0;           AC_SUBST([GNULIB_STRSEP])
+  GNULIB_STRSTR=0;           AC_SUBST([GNULIB_STRSTR])
+  GNULIB_STRCASESTR=0;       AC_SUBST([GNULIB_STRCASESTR])
+  GNULIB_STRTOK_R=0;         AC_SUBST([GNULIB_STRTOK_R])
+  GNULIB_MBSLEN=0;           AC_SUBST([GNULIB_MBSLEN])
+  GNULIB_MBSNLEN=0;          AC_SUBST([GNULIB_MBSNLEN])
+  GNULIB_MBSCHR=0;           AC_SUBST([GNULIB_MBSCHR])
+  GNULIB_MBSRCHR=0;          AC_SUBST([GNULIB_MBSRCHR])
+  GNULIB_MBSSTR=0;           AC_SUBST([GNULIB_MBSSTR])
+  GNULIB_MBSCASECMP=0;       AC_SUBST([GNULIB_MBSCASECMP])
+  GNULIB_MBSNCASECMP=0;      AC_SUBST([GNULIB_MBSNCASECMP])
+  GNULIB_MBSPCASECMP=0;      AC_SUBST([GNULIB_MBSPCASECMP])
+  GNULIB_MBSCASESTR=0;       AC_SUBST([GNULIB_MBSCASESTR])
+  GNULIB_MBSCSPN=0;          AC_SUBST([GNULIB_MBSCSPN])
+  GNULIB_MBSPBRK=0;          AC_SUBST([GNULIB_MBSPBRK])
+  GNULIB_MBSSPN=0;           AC_SUBST([GNULIB_MBSSPN])
+  GNULIB_MBSSEP=0;           AC_SUBST([GNULIB_MBSSEP])
+  GNULIB_MBSTOK_R=0;         AC_SUBST([GNULIB_MBSTOK_R])
+  GNULIB_STRERROR=0;         AC_SUBST([GNULIB_STRERROR])
+  GNULIB_STRERROR_R=0;       AC_SUBST([GNULIB_STRERROR_R])
+  GNULIB_STRERRORNAME_NP=0;  AC_SUBST([GNULIB_STRERRORNAME_NP])
+  GNULIB_SIGABBREV_NP=0;     AC_SUBST([GNULIB_SIGABBREV_NP])
+  GNULIB_SIGDESCR_NP=0;      AC_SUBST([GNULIB_SIGDESCR_NP])
+  GNULIB_STRSIGNAL=0;        AC_SUBST([GNULIB_STRSIGNAL])
+  GNULIB_STRVERSCMP=0;       AC_SUBST([GNULIB_STRVERSCMP])
+  HAVE_MBSLEN=0;             AC_SUBST([HAVE_MBSLEN])
+  dnl Support Microsoft deprecated alias function names by default.
+  GNULIB_MDA_MEMCCPY=1;      AC_SUBST([GNULIB_MDA_MEMCCPY])
+  GNULIB_MDA_STRDUP=1;       AC_SUBST([GNULIB_MDA_STRDUP])
+  dnl Assume proper GNU behavior unless another module says otherwise.
+  HAVE_EXPLICIT_BZERO=1;        AC_SUBST([HAVE_EXPLICIT_BZERO])
+  HAVE_FFSL=1;                  AC_SUBST([HAVE_FFSL])
+  HAVE_FFSLL=1;                 AC_SUBST([HAVE_FFSLL])
+  HAVE_DECL_MEMMEM=1;           AC_SUBST([HAVE_DECL_MEMMEM])
+  HAVE_MEMPCPY=1;               AC_SUBST([HAVE_MEMPCPY])
+  HAVE_DECL_MEMRCHR=1;          AC_SUBST([HAVE_DECL_MEMRCHR])
+  HAVE_RAWMEMCHR=1;             AC_SUBST([HAVE_RAWMEMCHR])
+  HAVE_STPCPY=1;                AC_SUBST([HAVE_STPCPY])
+  HAVE_STPNCPY=1;               AC_SUBST([HAVE_STPNCPY])
+  HAVE_STRCHRNUL=1;             AC_SUBST([HAVE_STRCHRNUL])
+  HAVE_DECL_STRDUP=1;           AC_SUBST([HAVE_DECL_STRDUP])
+  HAVE_DECL_STRNDUP=1;          AC_SUBST([HAVE_DECL_STRNDUP])
+  HAVE_DECL_STRNLEN=1;          AC_SUBST([HAVE_DECL_STRNLEN])
+  HAVE_STRPBRK=1;               AC_SUBST([HAVE_STRPBRK])
+  HAVE_STRSEP=1;                AC_SUBST([HAVE_STRSEP])
+  HAVE_STRCASESTR=1;            AC_SUBST([HAVE_STRCASESTR])
+  HAVE_DECL_STRTOK_R=1;         AC_SUBST([HAVE_DECL_STRTOK_R])
+  HAVE_DECL_STRERROR_R=1;       AC_SUBST([HAVE_DECL_STRERROR_R])
+  HAVE_STRERRORNAME_NP=1;       AC_SUBST([HAVE_STRERRORNAME_NP])
+  HAVE_SIGABBREV_NP=1;          AC_SUBST([HAVE_SIGABBREV_NP])
+  HAVE_SIGDESCR_NP=1;           AC_SUBST([HAVE_SIGDESCR_NP])
+  HAVE_DECL_STRSIGNAL=1;        AC_SUBST([HAVE_DECL_STRSIGNAL])
+  HAVE_STRVERSCMP=1;            AC_SUBST([HAVE_STRVERSCMP])
+  REPLACE_MEMCHR=0;             AC_SUBST([REPLACE_MEMCHR])
+  REPLACE_MEMMEM=0;             AC_SUBST([REPLACE_MEMMEM])
+  REPLACE_STPNCPY=0;            AC_SUBST([REPLACE_STPNCPY])
+  REPLACE_STRCHRNUL=0;          AC_SUBST([REPLACE_STRCHRNUL])
+  REPLACE_STRDUP=0;             AC_SUBST([REPLACE_STRDUP])
+  REPLACE_STRNCAT=0;            AC_SUBST([REPLACE_STRNCAT])
+  REPLACE_STRNDUP=0;            AC_SUBST([REPLACE_STRNDUP])
+  REPLACE_STRNLEN=0;            AC_SUBST([REPLACE_STRNLEN])
+  REPLACE_STRSTR=0;             AC_SUBST([REPLACE_STRSTR])
+  REPLACE_STRCASESTR=0;         AC_SUBST([REPLACE_STRCASESTR])
+  REPLACE_STRTOK_R=0;           AC_SUBST([REPLACE_STRTOK_R])
+  REPLACE_STRERROR=0;           AC_SUBST([REPLACE_STRERROR])
+  REPLACE_STRERROR_R=0;         AC_SUBST([REPLACE_STRERROR_R])
+  REPLACE_STRERRORNAME_NP=0;    AC_SUBST([REPLACE_STRERRORNAME_NP])
+  REPLACE_STRSIGNAL=0;          AC_SUBST([REPLACE_STRSIGNAL])
+  UNDEFINE_STRTOK_R=0;          AC_SUBST([UNDEFINE_STRTOK_R])
+])
diff --git a/m4/strings_h.m4 b/m4/strings_h.m4
new file mode 100644
index 0000000..4aadca0
--- /dev/null
+++ b/m4/strings_h.m4
@@ -0,0 +1,52 @@
+# Configure a replacement for <strings.h>.
+# serial 6
+
+# Copyright (C) 2007, 2009-2020 Free Software Foundation, Inc.
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_HEADER_STRINGS_H],
+[
+  dnl Use AC_REQUIRE here, so that the default behavior below is expanded
+  dnl once only, before all statements that occur in other macros.
+  AC_REQUIRE([gl_HEADER_STRINGS_H_BODY])
+])
+
+AC_DEFUN([gl_HEADER_STRINGS_H_BODY],
+[
+  AC_REQUIRE([gl_HEADER_STRINGS_H_DEFAULTS])
+
+  gl_CHECK_NEXT_HEADERS([strings.h])
+  if test $ac_cv_header_strings_h = yes; then
+    HAVE_STRINGS_H=1
+  else
+    HAVE_STRINGS_H=0
+  fi
+  AC_SUBST([HAVE_STRINGS_H])
+
+  dnl Check for declarations of anything we want to poison if the
+  dnl corresponding gnulib module is not in use.
+  gl_WARN_ON_USE_PREPARE([[
+    /* Minix 3.1.8 has a bug: <sys/types.h> must be included before
+       <strings.h>.  */
+    #include <sys/types.h>
+    #include <strings.h>
+    ]], [ffs strcasecmp strncasecmp])
+])
+
+AC_DEFUN([gl_STRINGS_MODULE_INDICATOR],
+[
+  dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
+  AC_REQUIRE([gl_HEADER_STRINGS_H_DEFAULTS])
+  gl_MODULE_INDICATOR_SET_VARIABLE([$1])
+])
+
+AC_DEFUN([gl_HEADER_STRINGS_H_DEFAULTS],
+[
+  GNULIB_FFS=0;            AC_SUBST([GNULIB_FFS])
+  dnl Assume proper GNU behavior unless another module says otherwise.
+  HAVE_FFS=1;              AC_SUBST([HAVE_FFS])
+  HAVE_STRCASECMP=1;       AC_SUBST([HAVE_STRCASECMP])
+  HAVE_DECL_STRNCASECMP=1; AC_SUBST([HAVE_DECL_STRNCASECMP])
+])
diff --git a/m4/strndup.m4 b/m4/strndup.m4
new file mode 100644
index 0000000..006a31a
--- /dev/null
+++ b/m4/strndup.m4
@@ -0,0 +1,58 @@
+# strndup.m4 serial 22
+dnl Copyright (C) 2002-2003, 2005-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_STRNDUP],
+[
+  dnl Persuade glibc <string.h> to declare strndup().
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
+
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS])
+  AC_CHECK_DECLS_ONCE([strndup])
+  AC_CHECK_FUNCS_ONCE([strndup])
+  if test $ac_cv_have_decl_strndup = no; then
+    HAVE_DECL_STRNDUP=0
+  fi
+
+  if test $ac_cv_func_strndup = yes; then
+    HAVE_STRNDUP=1
+    # AIX 4.3.3, AIX 5.1 have a function that fails to add the terminating '\0'.
+    AC_CACHE_CHECK([for working strndup], [gl_cv_func_strndup_works],
+      [AC_RUN_IFELSE([
+         AC_LANG_PROGRAM([[#include <string.h>
+                           #include <stdlib.h>]], [[
+#if !HAVE_DECL_STRNDUP
+  extern
+  #ifdef __cplusplus
+  "C"
+  #endif
+  char *strndup (const char *, size_t);
+#endif
+  int result;
+  char *s;
+  s = strndup ("some longer string", 15);
+  free (s);
+  s = strndup ("shorter string", 13);
+  result = s[13] != '\0';
+  free (s);
+  return result;]])],
+         [gl_cv_func_strndup_works=yes],
+         [gl_cv_func_strndup_works=no],
+         [
+changequote(,)dnl
+          case $host_os in
+            aix | aix[3-6]*) gl_cv_func_strndup_works="guessing no";;
+            *)               gl_cv_func_strndup_works="guessing yes";;
+          esac
+changequote([,])dnl
+         ])])
+    case $gl_cv_func_strndup_works in
+      *no) REPLACE_STRNDUP=1 ;;
+    esac
+  else
+    HAVE_STRNDUP=0
+  fi
+])
diff --git a/m4/strnlen.m4 b/m4/strnlen.m4
new file mode 100644
index 0000000..71b8e1b
--- /dev/null
+++ b/m4/strnlen.m4
@@ -0,0 +1,30 @@
+# strnlen.m4 serial 13
+dnl Copyright (C) 2002-2003, 2005-2007, 2009-2020 Free Software Foundation,
+dnl Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_STRNLEN],
+[
+  AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS])
+
+  dnl Persuade glibc <string.h> to declare strnlen().
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
+
+  AC_CHECK_DECLS_ONCE([strnlen])
+  if test $ac_cv_have_decl_strnlen = no; then
+    HAVE_DECL_STRNLEN=0
+  else
+    m4_pushdef([AC_LIBOBJ], [:])
+    dnl Note: AC_FUNC_STRNLEN does AC_LIBOBJ([strnlen]).
+    AC_FUNC_STRNLEN
+    m4_popdef([AC_LIBOBJ])
+    if test $ac_cv_func_strnlen_working = no; then
+      REPLACE_STRNLEN=1
+    fi
+  fi
+])
+
+# Prerequisites of lib/strnlen.c.
+AC_DEFUN([gl_PREREQ_STRNLEN], [:])
diff --git a/m4/strpbrk.m4 b/m4/strpbrk.m4
new file mode 100644
index 0000000..7e74337
--- /dev/null
+++ b/m4/strpbrk.m4
@@ -0,0 +1,17 @@
+# strpbrk.m4 serial 6
+dnl Copyright (C) 2002-2003, 2007, 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_STRPBRK],
+[
+  AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS])
+  AC_CHECK_FUNCS([strpbrk])
+  if test $ac_cv_func_strpbrk = no; then
+    HAVE_STRPBRK=0
+  fi
+])
+
+# Prerequisites of lib/strpbrk.c.
+AC_DEFUN([gl_PREREQ_STRPBRK], [:])
diff --git a/m4/strptime.m4 b/m4/strptime.m4
new file mode 100644
index 0000000..d4b9290
--- /dev/null
+++ b/m4/strptime.m4
@@ -0,0 +1,22 @@
+# strptime.m4 serial 7
+dnl Copyright (C) 2007, 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_STRPTIME],
+[
+  AC_REQUIRE([gl_HEADER_TIME_H_DEFAULTS])
+  AC_REQUIRE([AC_C_RESTRICT])
+  AC_CHECK_FUNCS_ONCE([strptime])
+  if test $ac_cv_func_strptime != yes; then
+    HAVE_STRPTIME=0
+  fi
+])
+
+# Prerequisites of lib/strptime.c.
+AC_DEFUN([gl_PREREQ_STRPTIME],
+[
+  AC_REQUIRE([gl_TM_GMTOFF])
+  :
+])
diff --git a/m4/strtok_r.m4 b/m4/strtok_r.m4
new file mode 100644
index 0000000..2da132c
--- /dev/null
+++ b/m4/strtok_r.m4
@@ -0,0 +1,73 @@
+# strtok_r.m4 serial 15
+dnl Copyright (C) 2002-2004, 2006-2007, 2009-2020 Free Software Foundation,
+dnl Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_STRTOK_R],
+[
+  dnl The strtok_r() declaration in lib/string.in.h uses 'restrict'.
+  AC_REQUIRE([AC_C_RESTRICT])
+
+  AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_CHECK_FUNCS([strtok_r])
+  if test $ac_cv_func_strtok_r = yes; then
+    HAVE_STRTOK_R=1
+    dnl glibc 2.7 has a bug in strtok_r that causes a segmentation fault
+    dnl when the second argument to strtok_r is a constant string that has
+    dnl exactly one byte and compiling with optimization.  This bug is, for
+    dnl example, present in the glibc 2.7-18 package in Debian "lenny".
+    dnl See <https://sourceware.org/bugzilla/show_bug.cgi?id=5614>.
+    AC_CACHE_CHECK([whether strtok_r works], [gl_cv_func_strtok_r_works],
+      [AC_RUN_IFELSE(
+         [AC_LANG_PROGRAM([[
+              #ifndef __OPTIMIZE__
+              # define __OPTIMIZE__ 1
+              #endif
+              #undef __OPTIMIZE_SIZE__
+              #undef __NO_INLINE__
+              #include <stdlib.h>
+              #include <string.h>
+            ]],
+            [[static const char dummy[] = "\177\01a";
+              char delimiters[] = "xxxxxxxx";
+              char *save_ptr = (char *) dummy;
+              strtok_r (delimiters, "x", &save_ptr);
+              strtok_r (NULL, "x", &save_ptr);
+              return 0;
+            ]])
+         ],
+         [gl_cv_func_strtok_r_works=yes],
+         [gl_cv_func_strtok_r_works=no],
+         [case "$host_os" in
+                           # Guess no on glibc systems.
+            *-gnu* | gnu*) gl_cv_func_strtok_r_works="guessing no" ;;
+                           # Guess yes on native Windows.
+            mingw*)        gl_cv_func_strtok_r_works="guessing yes" ;;
+            *)             gl_cv_func_strtok_r_works="guessing yes" ;;
+          esac
+         ])
+      ])
+    case "$gl_cv_func_strtok_r_works" in
+      *no)
+        dnl We could set REPLACE_STRTOK_R=1 here, but it's only the macro
+        dnl version in <bits/string2.h> which is wrong. The code compiled
+        dnl into libc is fine.
+        UNDEFINE_STRTOK_R=1
+        ;;
+    esac
+  else
+    HAVE_STRTOK_R=0
+  fi
+  AC_CHECK_DECLS_ONCE([strtok_r])
+  if test $ac_cv_have_decl_strtok_r = no; then
+    HAVE_DECL_STRTOK_R=0
+  fi
+])
+
+# Prerequisites of lib/strtok_r.c.
+AC_DEFUN([gl_PREREQ_STRTOK_R], [
+  :
+])
diff --git a/m4/strtol.m4 b/m4/strtol.m4
new file mode 100644
index 0000000..eb19ffe
--- /dev/null
+++ b/m4/strtol.m4
@@ -0,0 +1,10 @@
+# strtol.m4 serial 6
+dnl Copyright (C) 2002-2003, 2006, 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_STRTOL],
+[
+  AC_CHECK_FUNCS([strtol])
+])
diff --git a/m4/strtoll.m4 b/m4/strtoll.m4
new file mode 100644
index 0000000..edcde3b
--- /dev/null
+++ b/m4/strtoll.m4
@@ -0,0 +1,19 @@
+# strtoll.m4 serial 8
+dnl Copyright (C) 2002, 2004, 2006, 2008-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_STRTOLL],
+[
+  AC_REQUIRE([gl_STDLIB_H_DEFAULTS])
+  AC_CHECK_FUNCS([strtoll])
+  if test $ac_cv_func_strtoll = no; then
+    HAVE_STRTOLL=0
+  fi
+])
+
+# Prerequisites of lib/strtoll.c.
+AC_DEFUN([gl_PREREQ_STRTOLL], [
+  :
+])
diff --git a/m4/symlink.m4 b/m4/symlink.m4
new file mode 100644
index 0000000..9cfdf93
--- /dev/null
+++ b/m4/symlink.m4
@@ -0,0 +1,55 @@
+# serial 9
+# See if we need to provide symlink replacement.
+
+dnl Copyright (C) 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+# Written by Eric Blake.
+
+AC_DEFUN([gl_FUNC_SYMLINK],
+[
+  AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_CHECK_FUNCS_ONCE([symlink])
+  dnl The best we can do on mingw is provide a dummy that always fails, so
+  dnl that compilation can proceed with fewer ifdefs.  On FreeBSD 7.2, AIX 7.1,
+  dnl and Solaris 9, we want to fix a bug with trailing slash handling.
+  if test $ac_cv_func_symlink = no; then
+    HAVE_SYMLINK=0
+  else
+    AC_CACHE_CHECK([whether symlink handles trailing slash correctly],
+      [gl_cv_func_symlink_works],
+      [AC_RUN_IFELSE(
+         [AC_LANG_PROGRAM(
+           [[#include <unistd.h>
+           ]],
+           [[int result = 0;
+             if (!symlink ("a", "conftest.link/"))
+               result |= 1;
+             if (symlink ("conftest.f", "conftest.lnk2"))
+               result |= 2;
+             else if (!symlink ("a", "conftest.lnk2/"))
+               result |= 4;
+             return result;
+           ]])],
+         [gl_cv_func_symlink_works=yes], [gl_cv_func_symlink_works=no],
+         [case "$host_os" in
+                             # Guess yes on Linux systems.
+            linux-* | linux) gl_cv_func_symlink_works="guessing yes" ;;
+                             # Guess yes on glibc systems.
+            *-gnu* | gnu*)   gl_cv_func_symlink_works="guessing yes" ;;
+                             # If we don't know, obey --enable-cross-guesses.
+            *)               gl_cv_func_symlink_works="$gl_cross_guess_normal" ;;
+          esac
+         ])
+      rm -f conftest.f conftest.link conftest.lnk2])
+    case "$gl_cv_func_symlink_works" in
+      *yes) ;;
+      *)
+        REPLACE_SYMLINK=1
+        ;;
+    esac
+  fi
+])
diff --git a/m4/sys_file_h.m4 b/m4/sys_file_h.m4
new file mode 100644
index 0000000..045e01b
--- /dev/null
+++ b/m4/sys_file_h.m4
@@ -0,0 +1,41 @@
+# Configure a replacement for <sys/file.h>.
+# serial 6
+
+# Copyright (C) 2008-2020 Free Software Foundation, Inc.
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+# Written by Richard W.M. Jones.
+
+AC_DEFUN([gl_HEADER_SYS_FILE_H],
+[
+  AC_REQUIRE([gl_HEADER_SYS_FILE_H_DEFAULTS])
+
+  dnl <sys/file.h> is always overridden, because of GNULIB_POSIXCHECK.
+  gl_CHECK_NEXT_HEADERS([sys/file.h])
+
+  if test $ac_cv_header_sys_file_h = yes; then
+    HAVE_SYS_FILE_H=1
+  else
+    HAVE_SYS_FILE_H=0
+  fi
+  AC_SUBST([HAVE_SYS_FILE_H])
+
+  dnl Check for declarations of anything we want to poison if the
+  dnl corresponding gnulib module is not in use.
+  gl_WARN_ON_USE_PREPARE([[#include <sys/file.h>
+    ]], [flock])
+])
+
+AC_DEFUN([gl_HEADER_SYS_FILE_MODULE_INDICATOR],
+[
+  AC_REQUIRE([gl_HEADER_SYS_FILE_H_DEFAULTS])
+  gl_MODULE_INDICATOR_SET_VARIABLE([$1])
+])
+
+AC_DEFUN([gl_HEADER_SYS_FILE_H_DEFAULTS],
+[
+  GNULIB_FLOCK=0;        AC_SUBST([GNULIB_FLOCK])
+  HAVE_FLOCK=1;          AC_SUBST([HAVE_FLOCK])
+])
diff --git a/m4/sys_ioctl_h.m4 b/m4/sys_ioctl_h.m4
new file mode 100644
index 0000000..98d24e8
--- /dev/null
+++ b/m4/sys_ioctl_h.m4
@@ -0,0 +1,64 @@
+# sys_ioctl_h.m4 serial 12
+dnl Copyright (C) 2008-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl Written by Bruno Haible.
+
+AC_DEFUN([gl_SYS_IOCTL_H],
+[
+  dnl Use AC_REQUIRE here, so that the default behavior below is expanded
+  dnl once only, before all statements that occur in other macros.
+  AC_REQUIRE([gl_SYS_IOCTL_H_DEFAULTS])
+
+  AC_CHECK_HEADERS_ONCE([sys/ioctl.h])
+  if test $ac_cv_header_sys_ioctl_h = yes; then
+    HAVE_SYS_IOCTL_H=1
+    dnl Test whether <sys/ioctl.h> declares ioctl(), or whether some other
+    dnl header file, such as <unistd.h> or <stropts.h>, is needed for that.
+    AC_CACHE_CHECK([whether <sys/ioctl.h> declares ioctl],
+      [gl_cv_decl_ioctl_in_sys_ioctl_h],
+      [dnl We cannot use AC_CHECK_DECL because it produces its own messages.
+       AC_COMPILE_IFELSE(
+         [AC_LANG_PROGRAM(
+            [[#include <sys/ioctl.h>]],
+            [[(void) ioctl;]])],
+         [gl_cv_decl_ioctl_in_sys_ioctl_h=yes],
+         [gl_cv_decl_ioctl_in_sys_ioctl_h=no])
+      ])
+  else
+    HAVE_SYS_IOCTL_H=0
+  fi
+  AC_SUBST([HAVE_SYS_IOCTL_H])
+  dnl <sys/ioctl.h> is always overridden, because of GNULIB_POSIXCHECK.
+  gl_CHECK_NEXT_HEADERS([sys/ioctl.h])
+
+  dnl Check for declarations of anything we want to poison if the
+  dnl corresponding gnulib module is not in use.
+  gl_WARN_ON_USE_PREPARE([[#include <sys/ioctl.h>
+/* Some platforms declare ioctl in the wrong header.  */
+#if !(defined __GLIBC__ && !defined __UCLIBC__)
+# include <unistd.h>
+#endif
+    ]], [ioctl])
+])
+
+AC_DEFUN([gl_SYS_IOCTL_MODULE_INDICATOR],
+[
+  dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
+  AC_REQUIRE([gl_SYS_IOCTL_H_DEFAULTS])
+  gl_MODULE_INDICATOR_SET_VARIABLE([$1])
+  dnl Define it also as a C macro, for the benefit of the unit tests.
+  gl_MODULE_INDICATOR_FOR_TESTS([$1])
+])
+
+AC_DEFUN([gl_SYS_IOCTL_H_DEFAULTS],
+[
+  GNULIB_IOCTL=0;         AC_SUBST([GNULIB_IOCTL])
+  dnl Assume proper GNU behavior unless another module says otherwise.
+  SYS_IOCTL_H_HAVE_WINSOCK2_H=0; AC_SUBST([SYS_IOCTL_H_HAVE_WINSOCK2_H])
+  SYS_IOCTL_H_HAVE_WINSOCK2_H_AND_USE_SOCKETS=0;
+                        AC_SUBST([SYS_IOCTL_H_HAVE_WINSOCK2_H_AND_USE_SOCKETS])
+  REPLACE_IOCTL=0;      AC_SUBST([REPLACE_IOCTL])
+])
diff --git a/m4/sys_random_h.m4 b/m4/sys_random_h.m4
new file mode 100644
index 0000000..8c5d537
--- /dev/null
+++ b/m4/sys_random_h.m4
@@ -0,0 +1,53 @@
+# sys_random_h.m4 serial 5
+dnl Copyright (C) 2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_HEADER_SYS_RANDOM],
+[
+  AC_REQUIRE([gl_SYS_RANDOM_H_DEFAULTS])
+  dnl <sys/random.h> is always overridden, because of GNULIB_POSIXCHECK.
+  gl_CHECK_NEXT_HEADERS([sys/random.h])
+  if test $ac_cv_header_sys_random_h = yes; then
+    HAVE_SYS_RANDOM_H=1
+  else
+    HAVE_SYS_RANDOM_H=0
+  fi
+  AC_SUBST([HAVE_SYS_RANDOM_H])
+
+  m4_ifdef([gl_UNISTD_H_DEFAULTS], [AC_REQUIRE([gl_UNISTD_H_DEFAULTS])])
+  if test $ac_cv_header_sys_random_h = yes; then
+    UNISTD_H_HAVE_SYS_RANDOM_H=1
+  fi
+
+  dnl Check for declarations of anything we want to poison if the
+  dnl corresponding gnulib module is not in use.
+  gl_WARN_ON_USE_PREPARE([[
+#if HAVE_SYS_RANDOM_H
+/* Additional includes are needed before <sys/random.h> on uClibc
+   and Mac OS X.  */
+# include <sys/types.h>
+# include <stdlib.h>
+# include <sys/random.h>
+#endif
+    ]],
+    [getrandom])
+])
+
+AC_DEFUN([gl_SYS_RANDOM_MODULE_INDICATOR],
+[
+  dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
+  AC_REQUIRE([gl_SYS_RANDOM_H_DEFAULTS])
+  gl_MODULE_INDICATOR_SET_VARIABLE([$1])
+  dnl Define it also as a C macro, for the benefit of the unit tests.
+  gl_MODULE_INDICATOR_FOR_TESTS([$1])
+])
+
+AC_DEFUN([gl_SYS_RANDOM_H_DEFAULTS],
+[
+  GNULIB_GETRANDOM=0;     AC_SUBST([GNULIB_GETRANDOM])
+  dnl Assume proper GNU behavior unless another module says otherwise.
+  HAVE_GETRANDOM=1;       AC_SUBST([HAVE_GETRANDOM])
+  REPLACE_GETRANDOM=0;    AC_SUBST([REPLACE_GETRANDOM])
+])
diff --git a/m4/sys_select_h.m4 b/m4/sys_select_h.m4
new file mode 100644
index 0000000..fa19bb6
--- /dev/null
+++ b/m4/sys_select_h.m4
@@ -0,0 +1,95 @@
+# sys_select_h.m4 serial 20
+dnl Copyright (C) 2006-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_HEADER_SYS_SELECT],
+[
+  AC_REQUIRE([AC_C_RESTRICT])
+  AC_REQUIRE([gl_SYS_SELECT_H_DEFAULTS])
+  AC_CACHE_CHECK([whether <sys/select.h> is self-contained],
+    [gl_cv_header_sys_select_h_selfcontained],
+    [
+      dnl Test against two bugs:
+      dnl 1. On many platforms, <sys/select.h> assumes prior inclusion of
+      dnl    <sys/types.h>.
+      dnl 2. On OSF/1 4.0, <sys/select.h> provides only a forward declaration
+      dnl    of 'struct timeval', and no definition of this type.
+      AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <sys/select.h>]],
+                                         [[struct timeval b;]])],
+        [gl_cv_header_sys_select_h_selfcontained=yes],
+        [gl_cv_header_sys_select_h_selfcontained=no])
+      dnl Test against another bug:
+      dnl 3. On Solaris 10, <sys/select.h> provides an FD_ZERO implementation
+      dnl    that relies on memset(), but without including <string.h>.
+      if test $gl_cv_header_sys_select_h_selfcontained = yes; then
+        AC_COMPILE_IFELSE(
+          [AC_LANG_PROGRAM([[#include <sys/select.h>]],
+                           [[int memset; int bzero;]])
+          ],
+          [AC_LINK_IFELSE(
+             [AC_LANG_PROGRAM([[#include <sys/select.h>]], [[
+                  #undef memset
+                  #define memset nonexistent_memset
+                  extern
+                  #ifdef __cplusplus
+                  "C"
+                  #endif
+                  void *memset (void *, int, unsigned long);
+                  #undef bzero
+                  #define bzero nonexistent_bzero
+                  extern
+                  #ifdef __cplusplus
+                  "C"
+                  #endif
+                  void bzero (void *, unsigned long);
+                  fd_set fds;
+                  FD_ZERO (&fds);
+                ]])
+             ],
+             [],
+             [gl_cv_header_sys_select_h_selfcontained=no])
+          ])
+      fi
+    ])
+  dnl <sys/select.h> is always overridden, because of GNULIB_POSIXCHECK.
+  gl_CHECK_NEXT_HEADERS([sys/select.h])
+  if test $ac_cv_header_sys_select_h = yes; then
+    HAVE_SYS_SELECT_H=1
+  else
+    HAVE_SYS_SELECT_H=0
+  fi
+  AC_SUBST([HAVE_SYS_SELECT_H])
+  gl_PREREQ_SYS_H_WINSOCK2
+
+  dnl Check for declarations of anything we want to poison if the
+  dnl corresponding gnulib module is not in use.
+  gl_WARN_ON_USE_PREPARE([[
+/* Some systems require prerequisite headers.  */
+#include <sys/types.h>
+#if !(defined __GLIBC__ && !defined __UCLIBC__) && HAVE_SYS_TIME_H
+# include <sys/time.h>
+#endif
+#include <sys/select.h>
+    ]], [pselect select])
+])
+
+AC_DEFUN([gl_SYS_SELECT_MODULE_INDICATOR],
+[
+  dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
+  AC_REQUIRE([gl_SYS_SELECT_H_DEFAULTS])
+  gl_MODULE_INDICATOR_SET_VARIABLE([$1])
+  dnl Define it also as a C macro, for the benefit of the unit tests.
+  gl_MODULE_INDICATOR_FOR_TESTS([$1])
+])
+
+AC_DEFUN([gl_SYS_SELECT_H_DEFAULTS],
+[
+  GNULIB_PSELECT=0; AC_SUBST([GNULIB_PSELECT])
+  GNULIB_SELECT=0; AC_SUBST([GNULIB_SELECT])
+  dnl Assume proper GNU behavior unless another module says otherwise.
+  HAVE_PSELECT=1; AC_SUBST([HAVE_PSELECT])
+  REPLACE_PSELECT=0; AC_SUBST([REPLACE_PSELECT])
+  REPLACE_SELECT=0; AC_SUBST([REPLACE_SELECT])
+])
diff --git a/m4/sys_socket_h.m4 b/m4/sys_socket_h.m4
new file mode 100644
index 0000000..bf902f0
--- /dev/null
+++ b/m4/sys_socket_h.m4
@@ -0,0 +1,190 @@
+# sys_socket_h.m4 serial 25
+dnl Copyright (C) 2005-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl From Simon Josefsson.
+
+AC_DEFUN([gl_HEADER_SYS_SOCKET],
+[
+  AC_REQUIRE([gl_SYS_SOCKET_H_DEFAULTS])
+  AC_REQUIRE([AC_CANONICAL_HOST])
+
+  dnl On OSF/1, the functions recv(), send(), recvfrom(), sendto() have
+  dnl old-style declarations (with return type 'int' instead of 'ssize_t')
+  dnl unless _POSIX_PII_SOCKET is defined.
+  case "$host_os" in
+    osf*)
+      AC_DEFINE([_POSIX_PII_SOCKET], [1],
+        [Define to 1 in order to get the POSIX compatible declarations
+         of socket functions.])
+      ;;
+  esac
+
+  AC_CACHE_CHECK([whether <sys/socket.h> is self-contained],
+    [gl_cv_header_sys_socket_h_selfcontained],
+    [
+      AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <sys/socket.h>]], [[]])],
+        [gl_cv_header_sys_socket_h_selfcontained=yes],
+        [gl_cv_header_sys_socket_h_selfcontained=no])
+    ])
+  if test $gl_cv_header_sys_socket_h_selfcontained = yes; then
+    dnl If the shutdown function exists, <sys/socket.h> should define
+    dnl SHUT_RD, SHUT_WR, SHUT_RDWR.
+    AC_CHECK_FUNCS([shutdown])
+    if test $ac_cv_func_shutdown = yes; then
+      AC_CACHE_CHECK([whether <sys/socket.h> defines the SHUT_* macros],
+        [gl_cv_header_sys_socket_h_shut],
+        [
+          AC_COMPILE_IFELSE(
+            [AC_LANG_PROGRAM([[#include <sys/socket.h>]],
+               [[int a[] = { SHUT_RD, SHUT_WR, SHUT_RDWR };]])],
+            [gl_cv_header_sys_socket_h_shut=yes],
+            [gl_cv_header_sys_socket_h_shut=no])
+        ])
+      if test $gl_cv_header_sys_socket_h_shut = no; then
+        SYS_SOCKET_H='sys/socket.h'
+      fi
+    fi
+  fi
+  # We need to check for ws2tcpip.h now.
+  gl_PREREQ_SYS_H_SOCKET
+  AC_CHECK_TYPES([struct sockaddr_storage, sa_family_t],,,[
+  /* sys/types.h is not needed according to POSIX, but the
+     sys/socket.h in i386-unknown-freebsd4.10 and
+     powerpc-apple-darwin5.5 required it. */
+#include <sys/types.h>
+#ifdef HAVE_SYS_SOCKET_H
+#include <sys/socket.h>
+#endif
+#ifdef HAVE_WS2TCPIP_H
+#include <ws2tcpip.h>
+#endif
+])
+  if test $ac_cv_type_struct_sockaddr_storage = no; then
+    HAVE_STRUCT_SOCKADDR_STORAGE=0
+  fi
+  if test $ac_cv_type_sa_family_t = no; then
+    HAVE_SA_FAMILY_T=0
+  fi
+  if test $ac_cv_type_struct_sockaddr_storage != no; then
+    AC_CHECK_MEMBERS([struct sockaddr_storage.ss_family],
+      [],
+      [HAVE_STRUCT_SOCKADDR_STORAGE_SS_FAMILY=0],
+      [#include <sys/types.h>
+       #ifdef HAVE_SYS_SOCKET_H
+       #include <sys/socket.h>
+       #endif
+       #ifdef HAVE_WS2TCPIP_H
+       #include <ws2tcpip.h>
+       #endif
+      ])
+  fi
+  if test $HAVE_STRUCT_SOCKADDR_STORAGE = 0 || test $HAVE_SA_FAMILY_T = 0 \
+     || test $HAVE_STRUCT_SOCKADDR_STORAGE_SS_FAMILY = 0; then
+    SYS_SOCKET_H='sys/socket.h'
+  fi
+  gl_PREREQ_SYS_H_WINSOCK2
+
+  dnl Check for declarations of anything we want to poison if the
+  dnl corresponding gnulib module is not in use.
+  gl_WARN_ON_USE_PREPARE([[
+/* Some systems require prerequisite headers.  */
+#include <sys/types.h>
+#include <sys/socket.h>
+    ]], [socket connect accept bind getpeername getsockname getsockopt
+    listen recv send recvfrom sendto setsockopt shutdown accept4])
+
+  AC_REQUIRE([AC_C_RESTRICT])
+])
+
+AC_DEFUN([gl_PREREQ_SYS_H_SOCKET],
+[
+  dnl Check prerequisites of the <sys/socket.h> replacement.
+  AC_REQUIRE([gl_CHECK_SOCKET_HEADERS])
+  gl_CHECK_NEXT_HEADERS([sys/socket.h])
+  if test $ac_cv_header_sys_socket_h = yes; then
+    HAVE_SYS_SOCKET_H=1
+  else
+    HAVE_SYS_SOCKET_H=0
+  fi
+  AC_SUBST([HAVE_SYS_SOCKET_H])
+  gl_PREREQ_SYS_H_WS2TCPIP
+])
+
+# Common prerequisites of the <sys/socket.h> replacement and of the
+# <sys/select.h> replacement.
+# Sets and substitutes HAVE_WINSOCK2_H.
+AC_DEFUN([gl_PREREQ_SYS_H_WINSOCK2],
+[
+  m4_ifdef([gl_UNISTD_H_DEFAULTS], [AC_REQUIRE([gl_UNISTD_H_DEFAULTS])])
+  m4_ifdef([gl_SYS_IOCTL_H_DEFAULTS], [AC_REQUIRE([gl_SYS_IOCTL_H_DEFAULTS])])
+  AC_CHECK_HEADERS_ONCE([sys/socket.h])
+  if test $ac_cv_header_sys_socket_h != yes; then
+    dnl We cannot use AC_CHECK_HEADERS_ONCE here, because that would make
+    dnl the check for those headers unconditional; yet cygwin reports
+    dnl that the headers are present but cannot be compiled (since on
+    dnl cygwin, all socket information should come from sys/socket.h).
+    AC_CHECK_HEADERS([winsock2.h])
+  fi
+  if test "$ac_cv_header_winsock2_h" = yes; then
+    HAVE_WINSOCK2_H=1
+    UNISTD_H_HAVE_WINSOCK2_H=1
+    SYS_IOCTL_H_HAVE_WINSOCK2_H=1
+  else
+    HAVE_WINSOCK2_H=0
+  fi
+  AC_SUBST([HAVE_WINSOCK2_H])
+])
+
+# Common prerequisites of the <sys/socket.h> replacement and of the
+# <arpa/inet.h> replacement.
+# Sets and substitutes HAVE_WS2TCPIP_H.
+AC_DEFUN([gl_PREREQ_SYS_H_WS2TCPIP],
+[
+  AC_REQUIRE([gl_CHECK_SOCKET_HEADERS])
+  if test $ac_cv_header_sys_socket_h = yes; then
+    HAVE_WS2TCPIP_H=0
+  else
+    if test $ac_cv_header_ws2tcpip_h = yes; then
+      HAVE_WS2TCPIP_H=1
+    else
+      HAVE_WS2TCPIP_H=0
+    fi
+  fi
+  AC_SUBST([HAVE_WS2TCPIP_H])
+])
+
+AC_DEFUN([gl_SYS_SOCKET_MODULE_INDICATOR],
+[
+  dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
+  AC_REQUIRE([gl_SYS_SOCKET_H_DEFAULTS])
+  gl_MODULE_INDICATOR_SET_VARIABLE([$1])
+  dnl Define it also as a C macro, for the benefit of the unit tests.
+  gl_MODULE_INDICATOR_FOR_TESTS([$1])
+])
+
+AC_DEFUN([gl_SYS_SOCKET_H_DEFAULTS],
+[
+  GNULIB_SOCKET=0;      AC_SUBST([GNULIB_SOCKET])
+  GNULIB_CONNECT=0;     AC_SUBST([GNULIB_CONNECT])
+  GNULIB_ACCEPT=0;      AC_SUBST([GNULIB_ACCEPT])
+  GNULIB_BIND=0;        AC_SUBST([GNULIB_BIND])
+  GNULIB_GETPEERNAME=0; AC_SUBST([GNULIB_GETPEERNAME])
+  GNULIB_GETSOCKNAME=0; AC_SUBST([GNULIB_GETSOCKNAME])
+  GNULIB_GETSOCKOPT=0;  AC_SUBST([GNULIB_GETSOCKOPT])
+  GNULIB_LISTEN=0;      AC_SUBST([GNULIB_LISTEN])
+  GNULIB_RECV=0;        AC_SUBST([GNULIB_RECV])
+  GNULIB_SEND=0;        AC_SUBST([GNULIB_SEND])
+  GNULIB_RECVFROM=0;    AC_SUBST([GNULIB_RECVFROM])
+  GNULIB_SENDTO=0;      AC_SUBST([GNULIB_SENDTO])
+  GNULIB_SETSOCKOPT=0;  AC_SUBST([GNULIB_SETSOCKOPT])
+  GNULIB_SHUTDOWN=0;    AC_SUBST([GNULIB_SHUTDOWN])
+  GNULIB_ACCEPT4=0;     AC_SUBST([GNULIB_ACCEPT4])
+  HAVE_STRUCT_SOCKADDR_STORAGE=1; AC_SUBST([HAVE_STRUCT_SOCKADDR_STORAGE])
+  HAVE_STRUCT_SOCKADDR_STORAGE_SS_FAMILY=1;
+                        AC_SUBST([HAVE_STRUCT_SOCKADDR_STORAGE_SS_FAMILY])
+  HAVE_SA_FAMILY_T=1;   AC_SUBST([HAVE_SA_FAMILY_T])
+  HAVE_ACCEPT4=1;       AC_SUBST([HAVE_ACCEPT4])
+])
diff --git a/m4/sys_stat_h.m4 b/m4/sys_stat_h.m4
new file mode 100644
index 0000000..14b72db
--- /dev/null
+++ b/m4/sys_stat_h.m4
@@ -0,0 +1,110 @@
+# sys_stat_h.m4 serial 36   -*- Autoconf -*-
+dnl Copyright (C) 2006-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl From Eric Blake.
+dnl Provide a GNU-like <sys/stat.h>.
+
+AC_DEFUN([gl_HEADER_SYS_STAT_H],
+[
+  AC_REQUIRE([gl_SYS_STAT_H_DEFAULTS])
+
+  dnl Check for broken stat macros.
+  AC_REQUIRE([AC_HEADER_STAT])
+
+  gl_CHECK_NEXT_HEADERS([sys/stat.h])
+
+  dnl Ensure the type mode_t gets defined.
+  AC_REQUIRE([AC_TYPE_MODE_T])
+
+  dnl Whether to enable precise timestamps in 'struct stat'.
+  m4_ifdef([gl_WINDOWS_STAT_TIMESPEC], [
+    AC_REQUIRE([gl_WINDOWS_STAT_TIMESPEC])
+  ], [
+    WINDOWS_STAT_TIMESPEC=0
+  ])
+  AC_SUBST([WINDOWS_STAT_TIMESPEC])
+
+  dnl Whether to ensure that struct stat.st_size is 64-bit wide.
+  m4_ifdef([gl_LARGEFILE], [
+    AC_REQUIRE([gl_LARGEFILE])
+  ], [
+    WINDOWS_64_BIT_ST_SIZE=0
+  ])
+  AC_SUBST([WINDOWS_64_BIT_ST_SIZE])
+
+  dnl Define types that are supposed to be defined in <sys/types.h> or
+  dnl <sys/stat.h>.
+  AC_CHECK_TYPE([nlink_t], [],
+    [AC_DEFINE([nlink_t], [int],
+       [Define to the type of st_nlink in struct stat, or a supertype.])],
+    [#include <sys/types.h>
+     #include <sys/stat.h>])
+
+  dnl Check for declarations of anything we want to poison if the
+  dnl corresponding gnulib module is not in use.
+  gl_WARN_ON_USE_PREPARE([[#include <sys/stat.h>
+    ]], [fchmodat fstat fstatat futimens getumask lchmod lstat
+    mkdirat mkfifo mkfifoat mknod mknodat stat utimensat])
+
+  AC_REQUIRE([AC_C_RESTRICT])
+])
+
+AC_DEFUN([gl_SYS_STAT_MODULE_INDICATOR],
+[
+  dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
+  AC_REQUIRE([gl_SYS_STAT_H_DEFAULTS])
+  gl_MODULE_INDICATOR_SET_VARIABLE([$1])
+  dnl Define it also as a C macro, for the benefit of the unit tests.
+  gl_MODULE_INDICATOR_FOR_TESTS([$1])
+])
+
+AC_DEFUN([gl_SYS_STAT_H_DEFAULTS],
+[
+  AC_REQUIRE([gl_UNISTD_H_DEFAULTS]) dnl for REPLACE_FCHDIR
+  GNULIB_FCHMODAT=0;    AC_SUBST([GNULIB_FCHMODAT])
+  GNULIB_FSTAT=0;       AC_SUBST([GNULIB_FSTAT])
+  GNULIB_FSTATAT=0;     AC_SUBST([GNULIB_FSTATAT])
+  GNULIB_FUTIMENS=0;    AC_SUBST([GNULIB_FUTIMENS])
+  GNULIB_GETUMASK=0;    AC_SUBST([GNULIB_GETUMASK])
+  GNULIB_LCHMOD=0;      AC_SUBST([GNULIB_LCHMOD])
+  GNULIB_LSTAT=0;       AC_SUBST([GNULIB_LSTAT])
+  GNULIB_MKDIR=0;       AC_SUBST([GNULIB_MKDIR])
+  GNULIB_MKDIRAT=0;     AC_SUBST([GNULIB_MKDIRAT])
+  GNULIB_MKFIFO=0;      AC_SUBST([GNULIB_MKFIFO])
+  GNULIB_MKFIFOAT=0;    AC_SUBST([GNULIB_MKFIFOAT])
+  GNULIB_MKNOD=0;       AC_SUBST([GNULIB_MKNOD])
+  GNULIB_MKNODAT=0;     AC_SUBST([GNULIB_MKNODAT])
+  GNULIB_STAT=0;        AC_SUBST([GNULIB_STAT])
+  GNULIB_UTIMENSAT=0;   AC_SUBST([GNULIB_UTIMENSAT])
+  GNULIB_OVERRIDES_STRUCT_STAT=0; AC_SUBST([GNULIB_OVERRIDES_STRUCT_STAT])
+  dnl Support Microsoft deprecated alias function names by default.
+  GNULIB_MDA_CHMOD=1;   AC_SUBST([GNULIB_MDA_CHMOD])
+  GNULIB_MDA_MKDIR=1;   AC_SUBST([GNULIB_MDA_MKDIR])
+  GNULIB_MDA_UMASK=1;   AC_SUBST([GNULIB_MDA_UMASK])
+  dnl Assume proper GNU behavior unless another module says otherwise.
+  HAVE_FCHMODAT=1;      AC_SUBST([HAVE_FCHMODAT])
+  HAVE_FSTATAT=1;       AC_SUBST([HAVE_FSTATAT])
+  HAVE_FUTIMENS=1;      AC_SUBST([HAVE_FUTIMENS])
+  HAVE_GETUMASK=1;      AC_SUBST([HAVE_GETUMASK])
+  HAVE_LCHMOD=1;        AC_SUBST([HAVE_LCHMOD])
+  HAVE_LSTAT=1;         AC_SUBST([HAVE_LSTAT])
+  HAVE_MKDIRAT=1;       AC_SUBST([HAVE_MKDIRAT])
+  HAVE_MKFIFO=1;        AC_SUBST([HAVE_MKFIFO])
+  HAVE_MKFIFOAT=1;      AC_SUBST([HAVE_MKFIFOAT])
+  HAVE_MKNOD=1;         AC_SUBST([HAVE_MKNOD])
+  HAVE_MKNODAT=1;       AC_SUBST([HAVE_MKNODAT])
+  HAVE_UTIMENSAT=1;     AC_SUBST([HAVE_UTIMENSAT])
+  REPLACE_FCHMODAT=0;   AC_SUBST([REPLACE_FCHMODAT])
+  REPLACE_FSTAT=0;      AC_SUBST([REPLACE_FSTAT])
+  REPLACE_FSTATAT=0;    AC_SUBST([REPLACE_FSTATAT])
+  REPLACE_FUTIMENS=0;   AC_SUBST([REPLACE_FUTIMENS])
+  REPLACE_LSTAT=0;      AC_SUBST([REPLACE_LSTAT])
+  REPLACE_MKDIR=0;      AC_SUBST([REPLACE_MKDIR])
+  REPLACE_MKFIFO=0;     AC_SUBST([REPLACE_MKFIFO])
+  REPLACE_MKNOD=0;      AC_SUBST([REPLACE_MKNOD])
+  REPLACE_STAT=0;       AC_SUBST([REPLACE_STAT])
+  REPLACE_UTIMENSAT=0;  AC_SUBST([REPLACE_UTIMENSAT])
+])
diff --git a/m4/sys_time_h.m4 b/m4/sys_time_h.m4
new file mode 100644
index 0000000..8fc8599
--- /dev/null
+++ b/m4/sys_time_h.m4
@@ -0,0 +1,110 @@
+# Configure a replacement for <sys/time.h>.
+# serial 9
+
+# Copyright (C) 2007, 2009-2020 Free Software Foundation, Inc.
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+# Written by Paul Eggert and Martin Lambers.
+
+AC_DEFUN([gl_HEADER_SYS_TIME_H],
+[
+  dnl Use AC_REQUIRE here, so that the REPLACE_GETTIMEOFDAY=0 statement
+  dnl below is expanded once only, before all REPLACE_GETTIMEOFDAY=1
+  dnl statements that occur in other macros.
+  AC_REQUIRE([gl_HEADER_SYS_TIME_H_BODY])
+])
+
+AC_DEFUN([gl_HEADER_SYS_TIME_H_BODY],
+[
+  AC_REQUIRE([AC_C_RESTRICT])
+  AC_REQUIRE([gl_HEADER_SYS_TIME_H_DEFAULTS])
+  AC_CHECK_HEADERS_ONCE([sys/time.h])
+  gl_CHECK_NEXT_HEADERS([sys/time.h])
+
+  if test $ac_cv_header_sys_time_h != yes; then
+    HAVE_SYS_TIME_H=0
+  fi
+
+  dnl On native Windows with MSVC, 'struct timeval' is defined in <winsock2.h>
+  dnl only. So include that header in the list.
+  gl_PREREQ_SYS_H_WINSOCK2
+  AC_CACHE_CHECK([for struct timeval], [gl_cv_sys_struct_timeval],
+    [AC_COMPILE_IFELSE(
+       [AC_LANG_PROGRAM(
+          [[#if HAVE_SYS_TIME_H
+             #include <sys/time.h>
+            #endif
+            #include <time.h>
+            #if HAVE_WINSOCK2_H
+            # include <winsock2.h>
+            #endif
+          ]],
+          [[static struct timeval x; x.tv_sec = x.tv_usec;]])],
+       [gl_cv_sys_struct_timeval=yes],
+       [gl_cv_sys_struct_timeval=no])
+    ])
+  if test $gl_cv_sys_struct_timeval != yes; then
+    HAVE_STRUCT_TIMEVAL=0
+  else
+    dnl On native Windows with a 64-bit 'time_t', 'struct timeval' is defined
+    dnl (in <sys/time.h> and <winsock2.h> for mingw64, in <winsock2.h> only
+    dnl for MSVC) with a tv_sec field of type 'long' (32-bit!), which is
+    dnl smaller than the 'time_t' type mandated by POSIX.
+    dnl On OpenBSD 5.1 amd64, tv_sec is 64 bits and time_t 32 bits, but
+    dnl that is good enough.
+    AC_CACHE_CHECK([for wide-enough struct timeval.tv_sec member],
+      [gl_cv_sys_struct_timeval_tv_sec],
+      [AC_COMPILE_IFELSE(
+         [AC_LANG_PROGRAM(
+            [[#if HAVE_SYS_TIME_H
+               #include <sys/time.h>
+              #endif
+              #include <time.h>
+              #if HAVE_WINSOCK2_H
+              # include <winsock2.h>
+              #endif
+            ]],
+            [[static struct timeval x;
+              typedef int verify_tv_sec_type[
+                sizeof (time_t) <= sizeof x.tv_sec ? 1 : -1
+              ];
+            ]])],
+         [gl_cv_sys_struct_timeval_tv_sec=yes],
+         [gl_cv_sys_struct_timeval_tv_sec=no])
+      ])
+    if test $gl_cv_sys_struct_timeval_tv_sec != yes; then
+      REPLACE_STRUCT_TIMEVAL=1
+    fi
+  fi
+
+  dnl Check for declarations of anything we want to poison if the
+  dnl corresponding gnulib module is not in use.
+  gl_WARN_ON_USE_PREPARE([[
+#if HAVE_SYS_TIME_H
+# include <sys/time.h>
+#endif
+#include <time.h>
+    ]], [gettimeofday])
+])
+
+AC_DEFUN([gl_SYS_TIME_MODULE_INDICATOR],
+[
+  dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
+  AC_REQUIRE([gl_HEADER_SYS_TIME_H_DEFAULTS])
+  gl_MODULE_INDICATOR_SET_VARIABLE([$1])
+  dnl Define it also as a C macro, for the benefit of the unit tests.
+  gl_MODULE_INDICATOR_FOR_TESTS([$1])
+])
+
+AC_DEFUN([gl_HEADER_SYS_TIME_H_DEFAULTS],
+[
+  GNULIB_GETTIMEOFDAY=0;     AC_SUBST([GNULIB_GETTIMEOFDAY])
+  dnl Assume POSIX behavior unless another module says otherwise.
+  HAVE_GETTIMEOFDAY=1;       AC_SUBST([HAVE_GETTIMEOFDAY])
+  HAVE_STRUCT_TIMEVAL=1;     AC_SUBST([HAVE_STRUCT_TIMEVAL])
+  HAVE_SYS_TIME_H=1;         AC_SUBST([HAVE_SYS_TIME_H])
+  REPLACE_GETTIMEOFDAY=0;    AC_SUBST([REPLACE_GETTIMEOFDAY])
+  REPLACE_STRUCT_TIMEVAL=0;  AC_SUBST([REPLACE_STRUCT_TIMEVAL])
+])
diff --git a/m4/sys_types_h.m4 b/m4/sys_types_h.m4
new file mode 100644
index 0000000..c3a691b
--- /dev/null
+++ b/m4/sys_types_h.m4
@@ -0,0 +1,58 @@
+# sys_types_h.m4 serial 11
+dnl Copyright (C) 2011-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN_ONCE([gl_SYS_TYPES_H],
+[
+  dnl Use sane struct stat types in OpenVMS 8.2 and later.
+  AC_DEFINE([_USE_STD_STAT], 1, [For standard stat data types on VMS.])
+
+  AC_REQUIRE([gl_SYS_TYPES_H_DEFAULTS])
+  gl_NEXT_HEADERS([sys/types.h])
+
+  dnl Ensure the type pid_t gets defined.
+  AC_REQUIRE([AC_TYPE_PID_T])
+
+  dnl Ensure the type mode_t gets defined.
+  AC_REQUIRE([AC_TYPE_MODE_T])
+
+  dnl Whether to override the 'off_t' type.
+  AC_REQUIRE([gl_TYPE_OFF_T])
+
+  dnl Whether to override the 'dev_t' and 'ino_t' types.
+  m4_ifdef([gl_WINDOWS_STAT_INODES], [
+    AC_REQUIRE([gl_WINDOWS_STAT_INODES])
+  ], [
+    WINDOWS_STAT_INODES=0
+  ])
+  AC_SUBST([WINDOWS_STAT_INODES])
+])
+
+AC_DEFUN([gl_SYS_TYPES_H_DEFAULTS],
+[
+])
+
+# This works around a buggy version in autoconf <= 2.69.
+# See <https://lists.gnu.org/r/autoconf/2016-08/msg00014.html>
+# The 2.70 version isn't quoted properly, so override it too.
+
+m4_version_prereq([2.70.1], [], [
+
+m4_undefine([AC_HEADER_MAJOR])
+AC_DEFUN([AC_HEADER_MAJOR],
+[AC_CHECK_HEADERS_ONCE([sys/types.h])
+AC_CHECK_HEADER([sys/mkdev.h],
+                [AC_DEFINE([MAJOR_IN_MKDEV], [1],
+                           [Define to 1 if `major', `minor', and `makedev' are
+                            declared in <mkdev.h>.])])
+if test $ac_cv_header_sys_mkdev_h = no; then
+  AC_CHECK_HEADER([sys/sysmacros.h],
+                  [AC_DEFINE([MAJOR_IN_SYSMACROS], [1],
+                             [Define to 1 if `major', `minor', and `makedev'
+                              are declared in <sysmacros.h>.])])
+fi
+])# AC_HEADER_MAJOR
+
+])
diff --git a/m4/sys_uio_h.m4 b/m4/sys_uio_h.m4
new file mode 100644
index 0000000..a255dea
--- /dev/null
+++ b/m4/sys_uio_h.m4
@@ -0,0 +1,31 @@
+# sys_uio_h.m4 serial 1
+dnl Copyright (C) 2011-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_HEADER_SYS_UIO],
+[
+  AC_REQUIRE([gl_SYS_UIO_H_DEFAULTS])
+  dnl <sys/uio.h> is always overridden, because of GNULIB_POSIXCHECK.
+  gl_CHECK_NEXT_HEADERS([sys/uio.h])
+  if test $ac_cv_header_sys_uio_h = yes; then
+    HAVE_SYS_UIO_H=1
+  else
+    HAVE_SYS_UIO_H=0
+  fi
+  AC_SUBST([HAVE_SYS_UIO_H])
+])
+
+AC_DEFUN([gl_SYS_UIO_MODULE_INDICATOR],
+[
+  dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
+  AC_REQUIRE([gl_SYS_UIO_H_DEFAULTS])
+  gl_MODULE_INDICATOR_SET_VARIABLE([$1])
+  dnl Define it also as a C macro, for the benefit of the unit tests.
+  gl_MODULE_INDICATOR_FOR_TESTS([$1])
+])
+
+AC_DEFUN([gl_SYS_UIO_H_DEFAULTS],
+[
+])
diff --git a/m4/sys_wait_h.m4 b/m4/sys_wait_h.m4
new file mode 100644
index 0000000..8596d13
--- /dev/null
+++ b/m4/sys_wait_h.m4
@@ -0,0 +1,36 @@
+# sys_wait_h.m4 serial 6
+dnl Copyright (C) 2008-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_SYS_WAIT_H],
+[
+  AC_REQUIRE([gl_SYS_WAIT_H_DEFAULTS])
+
+  dnl <sys/wait.h> is always overridden, because of GNULIB_POSIXCHECK.
+  gl_CHECK_NEXT_HEADERS([sys/wait.h])
+
+  dnl Ensure the type pid_t gets defined.
+  AC_REQUIRE([AC_TYPE_PID_T])
+
+  dnl Check for declarations of anything we want to poison if the
+  dnl corresponding gnulib module is not in use.
+  gl_WARN_ON_USE_PREPARE([[#include <sys/wait.h>]],
+    [waitpid])
+])
+
+AC_DEFUN([gl_SYS_WAIT_MODULE_INDICATOR],
+[
+  dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
+  AC_REQUIRE([gl_SYS_WAIT_H_DEFAULTS])
+  gl_MODULE_INDICATOR_SET_VARIABLE([$1])
+  dnl Define it also as a C macro, for the benefit of the unit tests.
+  gl_MODULE_INDICATOR_FOR_TESTS([$1])
+])
+
+AC_DEFUN([gl_SYS_WAIT_H_DEFAULTS],
+[
+  GNULIB_WAITPID=0; AC_SUBST([GNULIB_WAITPID])
+  dnl Assume proper GNU behavior unless another module says otherwise.
+])
diff --git a/m4/tempname.m4 b/m4/tempname.m4
new file mode 100644
index 0000000..da439f0
--- /dev/null
+++ b/m4/tempname.m4
@@ -0,0 +1,19 @@
+#serial 5
+
+# Copyright (C) 2006-2007, 2009-2020 Free Software Foundation, Inc.
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+# glibc provides __gen_tempname as a wrapper for mk[ds]temp.  Expose
+# it as a public API, and provide it on systems that are lacking.
+AC_DEFUN([gl_FUNC_GEN_TEMPNAME],
+[
+  gl_PREREQ_TEMPNAME
+])
+
+# Prerequisites of lib/tempname.c.
+AC_DEFUN([gl_PREREQ_TEMPNAME],
+[
+  :
+])
diff --git a/m4/threadlib.m4 b/m4/threadlib.m4
new file mode 100644
index 0000000..e03c34f
--- /dev/null
+++ b/m4/threadlib.m4
@@ -0,0 +1,622 @@
+# threadlib.m4 serial 29
+dnl Copyright (C) 2005-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl From Bruno Haible.
+
+AC_PREREQ([2.60])
+
+dnl The general structure of the multithreading modules in gnulib is that we
+dnl have three set of modules:
+dnl
+dnl   * POSIX API:
+dnl     pthread, which combines
+dnl       pthread-h
+dnl       pthread-thread
+dnl       pthread-once
+dnl       pthread-mutex
+dnl       pthread-rwlock
+dnl       pthread-cond
+dnl       pthread-tss
+dnl       pthread-spin
+dnl     sched_yield
+dnl
+dnl   * ISO C API:
+dnl     threads, which combines
+dnl       threads-h
+dnl       thrd
+dnl       mtx
+dnl       cnd
+dnl       tss
+dnl
+dnl   * Gnulib API, with an implementation that can be chosen at configure
+dnl     time through the option --enable-threads=...
+dnl       thread
+dnl       lock
+dnl       cond
+dnl       tls
+dnl       yield
+dnl
+dnl They are independent, except for the fact that
+dnl   - the implementation of the ISO C API may use the POSIX (or some other
+dnl     platform dependent) API,
+dnl   - the implementation of the Gnulib API may use the POSIX or ISO C or
+dnl     some other platform dependent API, depending on the --enable-threads
+dnl     option.
+dnl
+dnl This file contains macros for all of these APIs!
+
+dnl ============================================================================
+dnl Macros for all thread APIs
+
+AC_DEFUN([gl_ANYTHREADLIB_EARLY],
+[
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  if test -z "$gl_anythreadlib_early_done"; then
+    case "$host_os" in
+      osf*)
+        # On OSF/1, the compiler needs the flag -D_REENTRANT so that it
+        # groks <pthread.h>. cc also understands the flag -pthread, but
+        # we don't use it because 1. gcc-2.95 doesn't understand -pthread,
+        # 2. putting a flag into CPPFLAGS that has an effect on the linker
+        # causes the AC_LINK_IFELSE test below to succeed unexpectedly,
+        # leading to wrong values of LIBTHREAD and LTLIBTHREAD.
+        CPPFLAGS="$CPPFLAGS -D_REENTRANT"
+        ;;
+    esac
+    # Some systems optimize for single-threaded programs by default, and
+    # need special flags to disable these optimizations. For example, the
+    # definition of 'errno' in <errno.h>.
+    case "$host_os" in
+      aix* | freebsd*) CPPFLAGS="$CPPFLAGS -D_THREAD_SAFE" ;;
+      solaris*) CPPFLAGS="$CPPFLAGS -D_REENTRANT" ;;
+    esac
+    gl_anythreadlib_early_done=done
+  fi
+])
+
+dnl Checks whether the compiler and linker support weak declarations of symbols.
+
+AC_DEFUN([gl_WEAK_SYMBOLS],
+[
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  AC_CACHE_CHECK([whether imported symbols can be declared weak],
+    [gl_cv_have_weak],
+    [gl_cv_have_weak=no
+     dnl First, test whether the compiler accepts it syntactically.
+     AC_LINK_IFELSE(
+       [AC_LANG_PROGRAM(
+          [[extern void xyzzy ();
+#pragma weak xyzzy]],
+          [[xyzzy();]])],
+       [gl_cv_have_weak=maybe])
+     if test $gl_cv_have_weak = maybe; then
+       dnl Second, test whether it actually works. On Cygwin 1.7.2, with
+       dnl gcc 4.3, symbols declared weak always evaluate to the address 0.
+       AC_RUN_IFELSE(
+         [AC_LANG_SOURCE([[
+#include <stdio.h>
+#pragma weak fputs
+int main ()
+{
+  return (fputs == NULL);
+}]])],
+         [gl_cv_have_weak=yes],
+         [gl_cv_have_weak=no],
+         [dnl When cross-compiling, assume that only ELF platforms support
+          dnl weak symbols.
+          AC_EGREP_CPP([Extensible Linking Format],
+            [#ifdef __ELF__
+             Extensible Linking Format
+             #endif
+            ],
+            [gl_cv_have_weak="guessing yes"],
+            [gl_cv_have_weak="guessing no"])
+         ])
+     fi
+     dnl But when linking statically, weak symbols don't work.
+     case " $LDFLAGS " in
+       *" -static "*) gl_cv_have_weak=no ;;
+     esac
+     dnl Test for a bug in FreeBSD 11: A link error occurs when using a weak
+     dnl symbol and linking against a shared library that has a dependency on
+     dnl the shared library that defines the symbol.
+     case "$gl_cv_have_weak" in
+       *yes)
+         case "$host_os" in
+           freebsd* | dragonfly*)
+             : > conftest1.c
+             $CC $CPPFLAGS $CFLAGS $LDFLAGS -fPIC -shared -o libempty.so conftest1.c -lpthread >&AS_MESSAGE_LOG_FD 2>&1
+             cat <<EOF > conftest2.c
+#include <pthread.h>
+#pragma weak pthread_mutexattr_gettype
+int main ()
+{
+  return (pthread_mutexattr_gettype != NULL);
+}
+EOF
+             $CC $CPPFLAGS $CFLAGS $LDFLAGS -o conftest conftest2.c libempty.so >&AS_MESSAGE_LOG_FD 2>&1 \
+               || gl_cv_have_weak=no
+             rm -f conftest1.c libempty.so conftest2.c conftest
+             ;;
+         esac
+         ;;
+     esac
+    ])
+  case "$gl_cv_have_weak" in
+    *yes)
+      AC_DEFINE([HAVE_WEAK_SYMBOLS], [1],
+        [Define to 1 if the compiler and linker support weak declarations of symbols.])
+      ;;
+  esac
+])
+
+dnl ============================================================================
+dnl Macros for the POSIX API
+
+dnl gl_PTHREADLIB
+dnl -------------
+dnl Tests for the libraries needs for using the POSIX threads API.
+dnl Sets the variable LIBPTHREAD to the linker options for use in a Makefile.
+dnl Sets the variable LIBPMULTITHREAD, for programs that really need
+dnl multithread functionality. The difference between LIBPTHREAD and
+dnl LIBPMULTITHREAD is that on platforms supporting weak symbols, typically
+dnl LIBPTHREAD is empty whereas LIBPMULTITHREAD is not.
+dnl Sets the variable LIB_SCHED_YIELD to the linker options needed to use the
+dnl sched_yield() function.
+dnl Adds to CPPFLAGS the flag -D_REENTRANT or -D_THREAD_SAFE if needed for
+dnl multithread-safe programs.
+dnl Defines the C macro HAVE_PTHREAD_API if (at least parts of) the POSIX
+dnl threads API is available.
+
+dnl The guts of gl_PTHREADLIB. Needs to be expanded only once.
+
+AC_DEFUN([gl_PTHREADLIB_BODY],
+[
+  AC_REQUIRE([gl_ANYTHREADLIB_EARLY])
+  if test -z "$gl_pthreadlib_body_done"; then
+    gl_pthread_api=no
+    LIBPTHREAD=
+    LIBPMULTITHREAD=
+    # On OSF/1, the compiler needs the flag -pthread or -D_REENTRANT so that
+    # it groks <pthread.h>. It's added above, in gl_ANYTHREADLIB_EARLY.
+    AC_CHECK_HEADER([pthread.h],
+      [gl_have_pthread_h=yes], [gl_have_pthread_h=no])
+    if test "$gl_have_pthread_h" = yes; then
+      # Other possible tests:
+      #   -lpthreads (FSU threads, PCthreads)
+      #   -lgthreads
+      # Test whether both pthread_mutex_lock and pthread_mutexattr_init exist
+      # in libc. IRIX 6.5 has the first one in both libc and libpthread, but
+      # the second one only in libpthread, and lock.c needs it.
+      #
+      # If -pthread works, prefer it to -lpthread, since Ubuntu 14.04
+      # needs -pthread for some reason.  See:
+      # https://lists.gnu.org/r/bug-gnulib/2014-09/msg00023.html
+      save_LIBS=$LIBS
+      for gl_pthread in '' '-pthread'; do
+        LIBS="$LIBS $gl_pthread"
+        AC_LINK_IFELSE(
+          [AC_LANG_PROGRAM(
+             [[#include <pthread.h>
+               pthread_mutex_t m;
+               pthread_mutexattr_t ma;
+             ]],
+             [[pthread_mutex_lock (&m);
+               pthread_mutexattr_init (&ma);]])],
+          [gl_pthread_api=yes
+           LIBPTHREAD=$gl_pthread
+           LIBPMULTITHREAD=$gl_pthread])
+        LIBS=$save_LIBS
+        test $gl_pthread_api = yes && break
+      done
+
+      # Test for libpthread by looking for pthread_kill. (Not pthread_self,
+      # since it is defined as a macro on OSF/1.)
+      if test $gl_pthread_api = yes && test -z "$LIBPTHREAD"; then
+        # The program links fine without libpthread. But it may actually
+        # need to link with libpthread in order to create multiple threads.
+        AC_CHECK_LIB([pthread], [pthread_kill],
+          [LIBPMULTITHREAD=-lpthread
+           # On Solaris and HP-UX, most pthread functions exist also in libc.
+           # Therefore pthread_in_use() needs to actually try to create a
+           # thread: pthread_create from libc will fail, whereas
+           # pthread_create will actually create a thread.
+           # On Solaris 10 or newer, this test is no longer needed, because
+           # libc contains the fully functional pthread functions.
+           case "$host_os" in
+             solaris | solaris2.[1-9] | solaris2.[1-9].* | hpux*)
+               AC_DEFINE([PTHREAD_IN_USE_DETECTION_HARD], [1],
+                 [Define if the pthread_in_use() detection is hard.])
+           esac
+          ])
+      elif test $gl_pthread_api != yes; then
+        # Some library is needed. Try libpthread and libc_r.
+        AC_CHECK_LIB([pthread], [pthread_kill],
+          [gl_pthread_api=yes
+           LIBPTHREAD=-lpthread
+           LIBPMULTITHREAD=-lpthread])
+        if test $gl_pthread_api != yes; then
+          # For FreeBSD 4.
+          AC_CHECK_LIB([c_r], [pthread_kill],
+            [gl_pthread_api=yes
+             LIBPTHREAD=-lc_r
+             LIBPMULTITHREAD=-lc_r])
+        fi
+      fi
+    fi
+    AC_MSG_CHECKING([whether POSIX threads API is available])
+    AC_MSG_RESULT([$gl_pthread_api])
+    AC_SUBST([LIBPTHREAD])
+    AC_SUBST([LIBPMULTITHREAD])
+    if test $gl_pthread_api = yes; then
+      AC_DEFINE([HAVE_PTHREAD_API], [1],
+        [Define if you have the <pthread.h> header and the POSIX threads API.])
+    fi
+
+    dnl On some systems, sched_yield is in librt, rather than in libpthread.
+    AC_LINK_IFELSE(
+      [AC_LANG_PROGRAM(
+         [[#include <sched.h>]],
+         [[sched_yield ();]])],
+      [LIB_SCHED_YIELD=
+      ],
+      [dnl Solaris 7...10 has sched_yield in librt, not in libpthread or libc.
+       AC_CHECK_LIB([rt], [sched_yield], [LIB_SCHED_YIELD=-lrt],
+         [dnl Solaris 2.5.1, 2.6 has sched_yield in libposix4, not librt.
+          AC_CHECK_LIB([posix4], [sched_yield], [LIB_SCHED_YIELD=-lposix4])])
+      ])
+    AC_SUBST([LIB_SCHED_YIELD])
+
+    gl_pthreadlib_body_done=done
+  fi
+])
+
+AC_DEFUN([gl_PTHREADLIB],
+[
+  AC_REQUIRE([gl_ANYTHREADLIB_EARLY])
+  gl_PTHREADLIB_BODY
+])
+
+dnl ============================================================================
+dnl Macros for the ISO C API
+
+dnl gl_STDTHREADLIB
+dnl ---------------
+dnl Tests for the libraries needs for using the ISO C threads API.
+dnl Sets the variable LIBSTDTHREAD to the linker options for use in a Makefile.
+dnl Adds to CPPFLAGS the flag -D_REENTRANT or -D_THREAD_SAFE if needed for
+dnl multithread-safe programs.
+dnl Defines the C macro HAVE_THREADS_H if (at least parts of) the ISO C threads
+dnl API is available.
+
+dnl The guts of gl_STDTHREADLIB. Needs to be expanded only once.
+
+AC_DEFUN([gl_STDTHREADLIB_BODY],
+[
+  AC_REQUIRE([gl_ANYTHREADLIB_EARLY])
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  if test -z "$gl_stdthreadlib_body_done"; then
+    AC_CHECK_HEADERS_ONCE([threads.h])
+
+    case "$host_os" in
+      mingw*)
+        LIBSTDTHREAD=
+        ;;
+      *)
+        gl_PTHREADLIB_BODY
+        if test $ac_cv_header_threads_h = yes; then
+          dnl glibc >= 2.29 has thrd_create in libpthread.
+          dnl FreeBSD >= 10 has thrd_create in libstdthreads; this library depends
+          dnl on libpthread (for the symbol 'pthread_mutexattr_gettype').
+          dnl AIX >= 7.1 and Solaris >= 11.4 have thrd_create in libc.
+          AC_CHECK_FUNCS([thrd_create])
+          if test $ac_cv_func_thrd_create = yes; then
+            LIBSTDTHREAD=
+          else
+            AC_CHECK_LIB([stdthreads], [thrd_create], [
+              LIBSTDTHREAD='-lstdthreads -lpthread'
+            ], [
+              dnl Guess that thrd_create is in libpthread.
+              LIBSTDTHREAD="$LIBPMULTITHREAD"
+            ])
+          fi
+        else
+          dnl Libraries needed by thrd.c, mtx.c, cnd.c, tss.c.
+          LIBSTDTHREAD="$LIBPMULTITHREAD $LIB_SCHED_YIELD"
+        fi
+        ;;
+    esac
+    AC_SUBST([LIBSTDTHREAD])
+
+    AC_MSG_CHECKING([whether ISO C threads API is available])
+    AC_MSG_RESULT([$ac_cv_header_threads_h])
+    gl_stdthreadlib_body_done=done
+  fi
+])
+
+AC_DEFUN([gl_STDTHREADLIB],
+[
+  AC_REQUIRE([gl_ANYTHREADLIB_EARLY])
+  gl_STDTHREADLIB_BODY
+])
+
+dnl ============================================================================
+dnl Macros for the Gnulib API
+
+dnl gl_THREADLIB
+dnl ------------
+dnl Tests for a multithreading library to be used.
+dnl If the configure.ac contains a definition of the gl_THREADLIB_DEFAULT_NO
+dnl (it must be placed before the invocation of gl_THREADLIB_EARLY!), then the
+dnl default is 'no', otherwise it is system dependent. In both cases, the user
+dnl can change the choice through the options --enable-threads=choice or
+dnl --disable-threads.
+dnl Defines at most one of the macros USE_ISOC_THREADS, USE_POSIX_THREADS,
+dnl USE_ISOC_AND_POSIX_THREADS, USE_WINDOWS_THREADS.
+dnl The choice --enable-threads=isoc+posix is available only on platforms that
+dnl have both the ISO C and the POSIX threads APIs. It has the effect of using
+dnl the ISO C API for most things and the POSIX API only for creating and
+dnl controlling threads (because there is no equivalent to pthread_atfork in
+dnl the ISO C API).
+dnl Sets the variables LIBTHREAD and LTLIBTHREAD to the linker options for use
+dnl in a Makefile (LIBTHREAD for use without libtool, LTLIBTHREAD for use with
+dnl libtool).
+dnl Sets the variables LIBMULTITHREAD and LTLIBMULTITHREAD similarly, for
+dnl programs that really need multithread functionality. The difference
+dnl between LIBTHREAD and LIBMULTITHREAD is that on platforms supporting weak
+dnl symbols, typically LIBTHREAD is empty whereas LIBMULTITHREAD is not.
+dnl Adds to CPPFLAGS the flag -D_REENTRANT or -D_THREAD_SAFE if needed for
+dnl multithread-safe programs.
+dnl Since support for GNU pth was removed, $LTLIBTHREAD and $LIBTHREAD have the
+dnl same value, and similarly $LTLIBMULTITHREAD and $LIBMULTITHREAD have the
+dnl same value. Only system libraries are needed.
+
+AC_DEFUN([gl_THREADLIB_EARLY],
+[
+  AC_REQUIRE([gl_THREADLIB_EARLY_BODY])
+])
+
+dnl The guts of gl_THREADLIB_EARLY. Needs to be expanded only once.
+
+AC_DEFUN([gl_THREADLIB_EARLY_BODY],
+[
+  dnl Ordering constraints: This macro modifies CPPFLAGS in a way that
+  dnl influences the result of the autoconf tests that test for *_unlocked
+  dnl declarations, on AIX 5 at least. Therefore it must come early.
+  AC_BEFORE([$0], [gl_FUNC_GLIBC_UNLOCKED_IO])dnl
+  AC_BEFORE([$0], [gl_ARGP])dnl
+
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  dnl _GNU_SOURCE is needed for pthread_rwlock_t on glibc systems.
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
+  dnl Check for multithreading.
+  m4_ifdef([gl_THREADLIB_DEFAULT_NO],
+    [m4_divert_text([DEFAULTS], [gl_use_threads_default=no])],
+    [m4_divert_text([DEFAULTS], [gl_use_threads_default=])])
+  m4_divert_text([DEFAULTS], [gl_use_winpthreads_default=])
+  AC_ARG_ENABLE([threads],
+AS_HELP_STRING([--enable-threads={isoc|posix|isoc+posix|windows}], [specify multithreading API])m4_ifdef([gl_THREADLIB_DEFAULT_NO], [], [
+AS_HELP_STRING([--disable-threads], [build without multithread safety])]),
+    [gl_use_threads=$enableval],
+    [if test -n "$gl_use_threads_default"; then
+       gl_use_threads="$gl_use_threads_default"
+     else
+changequote(,)dnl
+       case "$host_os" in
+         dnl Disable multithreading by default on OSF/1, because it interferes
+         dnl with fork()/exec(): When msgexec is linked with -lpthread, its
+         dnl child process gets an endless segmentation fault inside execvp().
+         osf*) gl_use_threads=no ;;
+         dnl Disable multithreading by default on Cygwin 1.5.x, because it has
+         dnl bugs that lead to endless loops or crashes. See
+         dnl <https://cygwin.com/ml/cygwin/2009-08/msg00283.html>.
+         cygwin*)
+               case `uname -r` in
+                 1.[0-5].*) gl_use_threads=no ;;
+                 *)         gl_use_threads=yes ;;
+               esac
+               ;;
+         dnl Obey gl_AVOID_WINPTHREAD on mingw.
+         mingw*)
+               case "$gl_use_winpthreads_default" in
+                 yes) gl_use_threads=posix ;;
+                 no)  gl_use_threads=windows ;;
+                 *)   gl_use_threads=yes ;;
+               esac
+               ;;
+         *)    gl_use_threads=yes ;;
+       esac
+changequote([,])dnl
+     fi
+    ])
+  if test "$gl_use_threads" = yes \
+     || test "$gl_use_threads" = isoc \
+     || test "$gl_use_threads" = posix \
+     || test "$gl_use_threads" = isoc+posix; then
+    # For using <threads.h> or <pthread.h>:
+    gl_ANYTHREADLIB_EARLY
+  fi
+])
+
+dnl The guts of gl_THREADLIB. Needs to be expanded only once.
+
+AC_DEFUN([gl_THREADLIB_BODY],
+[
+  AC_REQUIRE([gl_THREADLIB_EARLY_BODY])
+  gl_threads_api=none
+  LIBTHREAD=
+  LTLIBTHREAD=
+  LIBMULTITHREAD=
+  LTLIBMULTITHREAD=
+  if test "$gl_use_threads" != no; then
+    dnl Check whether the compiler and linker support weak declarations.
+    gl_WEAK_SYMBOLS
+    if case "$gl_cv_have_weak" in *yes) true;; *) false;; esac; then
+      dnl If we use weak symbols to implement pthread_in_use / pth_in_use /
+      dnl thread_in_use, we also need to test whether the ISO C 11 thrd_create
+      dnl facility is in use.
+      AC_CHECK_HEADERS_ONCE([threads.h])
+      :
+    fi
+    if test "$gl_use_threads" = isoc || test "$gl_use_threads" = isoc+posix; then
+      AC_CHECK_HEADERS_ONCE([threads.h])
+      gl_have_isoc_threads="$ac_cv_header_threads_h"
+    fi
+    if test "$gl_use_threads" = yes \
+       || test "$gl_use_threads" = posix \
+       || test "$gl_use_threads" = isoc+posix; then
+      gl_PTHREADLIB_BODY
+      LIBTHREAD=$LIBPTHREAD LTLIBTHREAD=$LIBPTHREAD
+      LIBMULTITHREAD=$LIBPMULTITHREAD LTLIBMULTITHREAD=$LIBPMULTITHREAD
+      if test $gl_pthread_api = yes; then
+        if test "$gl_use_threads" = isoc+posix && test "$gl_have_isoc_threads" = yes; then
+          gl_threads_api='isoc+posix'
+          AC_DEFINE([USE_ISOC_AND_POSIX_THREADS], [1],
+            [Define if the combination of the ISO C and POSIX multithreading APIs can be used.])
+          LIBTHREAD= LTLIBTHREAD=
+        else
+          gl_threads_api=posix
+          AC_DEFINE([USE_POSIX_THREADS], [1],
+            [Define if the POSIX multithreading library can be used.])
+          if test -n "$LIBMULTITHREAD" || test -n "$LTLIBMULTITHREAD"; then
+            if case "$gl_cv_have_weak" in *yes) true;; *) false;; esac; then
+              AC_DEFINE([USE_POSIX_THREADS_WEAK], [1],
+                [Define if references to the POSIX multithreading library should be made weak.])
+              LIBTHREAD= LTLIBTHREAD=
+            else
+              case "$host_os" in
+                freebsd* | dragonfly*)
+                  if test "x$LIBTHREAD" != "x$LIBMULTITHREAD"; then
+                    dnl If weak symbols can't tell whether pthread_create(), pthread_key_create()
+                    dnl etc. will succeed, we need a runtime test.
+                    AC_DEFINE([PTHREAD_IN_USE_DETECTION_HARD], [1],
+                      [Define if the pthread_in_use() detection is hard.])
+                  fi
+                  ;;
+              esac
+            fi
+          fi
+        fi
+      fi
+    fi
+    if test $gl_threads_api = none; then
+      if test "$gl_use_threads" = isoc && test "$gl_have_isoc_threads" = yes; then
+        gl_STDTHREADLIB_BODY
+        LIBTHREAD=$LIBSTDTHREAD LTLIBTHREAD=$LIBSTDTHREAD
+        LIBMULTITHREAD=$LIBSTDTHREAD LTLIBMULTITHREAD=$LIBSTDTHREAD
+        gl_threads_api=isoc
+        AC_DEFINE([USE_ISOC_THREADS], [1],
+          [Define if the ISO C multithreading library can be used.])
+      fi
+    fi
+    if test $gl_threads_api = none; then
+      case "$gl_use_threads" in
+        yes | windows | win32) # The 'win32' is for backward compatibility.
+          if { case "$host_os" in
+                 mingw*) true;;
+                 *) false;;
+               esac
+             }; then
+            gl_threads_api=windows
+            AC_DEFINE([USE_WINDOWS_THREADS], [1],
+              [Define if the native Windows multithreading API can be used.])
+          fi
+          ;;
+      esac
+    fi
+  fi
+  AC_MSG_CHECKING([for multithread API to use])
+  AC_MSG_RESULT([$gl_threads_api])
+  AC_SUBST([LIBTHREAD])
+  AC_SUBST([LTLIBTHREAD])
+  AC_SUBST([LIBMULTITHREAD])
+  AC_SUBST([LTLIBMULTITHREAD])
+])
+
+AC_DEFUN([gl_THREADLIB],
+[
+  AC_REQUIRE([gl_THREADLIB_EARLY])
+  AC_REQUIRE([gl_THREADLIB_BODY])
+])
+
+
+dnl gl_DISABLE_THREADS
+dnl ------------------
+dnl Sets the gl_THREADLIB default so that threads are not used by default.
+dnl The user can still override it at installation time, by using the
+dnl configure option '--enable-threads'.
+
+AC_DEFUN([gl_DISABLE_THREADS], [
+  m4_divert_text([INIT_PREPARE], [gl_use_threads_default=no])
+])
+
+
+dnl gl_AVOID_WINPTHREAD
+dnl -------------------
+dnl Sets the gl_THREADLIB default so that on mingw, a dependency to the
+dnl libwinpthread DLL (mingw-w64 winpthreads library) is avoided.
+dnl The user can still override it at installation time, by using the
+dnl configure option '--enable-threads'.
+
+AC_DEFUN([gl_AVOID_WINPTHREAD], [
+  m4_divert_text([INIT_PREPARE], [gl_use_winpthreads_default=no])
+])
+
+
+dnl ============================================================================
+
+
+dnl Survey of platforms:
+dnl
+dnl Platform           Available  Compiler    Supports   test-lock
+dnl                    flavours   option      weak       result
+dnl ---------------    ---------  ---------   --------   ---------
+dnl Linux 2.4/glibc    posix      -lpthread       Y      OK
+dnl
+dnl GNU Hurd/glibc     posix
+dnl
+dnl Ubuntu 14.04       posix      -pthread        Y      OK
+dnl
+dnl FreeBSD 5.3        posix      -lc_r           Y
+dnl                    posix      -lkse ?         Y
+dnl                    posix      -lpthread ?     Y
+dnl                    posix      -lthr           Y
+dnl
+dnl FreeBSD 5.2        posix      -lc_r           Y
+dnl                    posix      -lkse           Y
+dnl                    posix      -lthr           Y
+dnl
+dnl FreeBSD 4.0,4.10   posix      -lc_r           Y      OK
+dnl
+dnl NetBSD 1.6         --
+dnl
+dnl OpenBSD 3.4        posix      -lpthread       Y      OK
+dnl
+dnl Mac OS X 10.[123]  posix      -lpthread       Y      OK
+dnl
+dnl Solaris 7,8,9      posix      -lpthread       Y      Sol 7,8: 0.0; Sol 9: OK
+dnl
+dnl HP-UX 11           posix      -lpthread       N (cc) OK
+dnl                                               Y (gcc)
+dnl
+dnl IRIX 6.5           posix      -lpthread       Y      0.5
+dnl
+dnl AIX 4.3,5.1        posix      -lpthread       N      AIX 4: 0.5; AIX 5: OK
+dnl
+dnl OSF/1 4.0,5.1      posix      -pthread (cc)   N      OK
+dnl                               -lpthread (gcc) Y
+dnl
+dnl Cygwin             posix      -lpthread       Y      OK
+dnl
+dnl Mingw              windows                    N      OK
+dnl
+dnl BeOS 5             --
+dnl
+dnl The test-lock result shows what happens if in test-lock.c EXPLICIT_YIELD is
+dnl turned off:
+dnl   OK if all three tests terminate OK,
+dnl   0.5 if the first test terminates OK but the second one loops endlessly,
+dnl   0.0 if the first test already loops endlessly.
diff --git a/m4/time_h.m4 b/m4/time_h.m4
new file mode 100644
index 0000000..0c38ac8
--- /dev/null
+++ b/m4/time_h.m4
@@ -0,0 +1,147 @@
+# Configure a more-standard replacement for <time.h>.
+
+# Copyright (C) 2000-2001, 2003-2007, 2009-2020 Free Software Foundation, Inc.
+
+# serial 13
+
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+# Written by Paul Eggert and Jim Meyering.
+
+AC_DEFUN([gl_HEADER_TIME_H],
+[
+  dnl Use AC_REQUIRE here, so that the default behavior below is expanded
+  dnl once only, before all statements that occur in other macros.
+  AC_REQUIRE([gl_HEADER_TIME_H_BODY])
+])
+
+AC_DEFUN([gl_HEADER_TIME_H_BODY],
+[
+  AC_REQUIRE([gl_HEADER_TIME_H_DEFAULTS])
+
+  gl_NEXT_HEADERS([time.h])
+  AC_REQUIRE([gl_CHECK_TYPE_STRUCT_TIMESPEC])
+
+  AC_REQUIRE([AC_C_RESTRICT])
+])
+
+dnl Check whether 'struct timespec' is declared
+dnl in time.h, sys/time.h, pthread.h, or unistd.h.
+
+AC_DEFUN([gl_CHECK_TYPE_STRUCT_TIMESPEC],
+[
+  AC_CHECK_HEADERS_ONCE([sys/time.h])
+  AC_CACHE_CHECK([for struct timespec in <time.h>],
+    [gl_cv_sys_struct_timespec_in_time_h],
+    [AC_COMPILE_IFELSE(
+       [AC_LANG_PROGRAM(
+          [[#include <time.h>
+          ]],
+          [[static struct timespec x; x.tv_sec = x.tv_nsec;]])],
+       [gl_cv_sys_struct_timespec_in_time_h=yes],
+       [gl_cv_sys_struct_timespec_in_time_h=no])])
+
+  TIME_H_DEFINES_STRUCT_TIMESPEC=0
+  SYS_TIME_H_DEFINES_STRUCT_TIMESPEC=0
+  PTHREAD_H_DEFINES_STRUCT_TIMESPEC=0
+  UNISTD_H_DEFINES_STRUCT_TIMESPEC=0
+  if test $gl_cv_sys_struct_timespec_in_time_h = yes; then
+    TIME_H_DEFINES_STRUCT_TIMESPEC=1
+  else
+    AC_CACHE_CHECK([for struct timespec in <sys/time.h>],
+      [gl_cv_sys_struct_timespec_in_sys_time_h],
+      [AC_COMPILE_IFELSE(
+         [AC_LANG_PROGRAM(
+            [[#include <sys/time.h>
+            ]],
+            [[static struct timespec x; x.tv_sec = x.tv_nsec;]])],
+         [gl_cv_sys_struct_timespec_in_sys_time_h=yes],
+         [gl_cv_sys_struct_timespec_in_sys_time_h=no])])
+    if test $gl_cv_sys_struct_timespec_in_sys_time_h = yes; then
+      SYS_TIME_H_DEFINES_STRUCT_TIMESPEC=1
+    else
+      AC_CACHE_CHECK([for struct timespec in <pthread.h>],
+        [gl_cv_sys_struct_timespec_in_pthread_h],
+        [AC_COMPILE_IFELSE(
+           [AC_LANG_PROGRAM(
+              [[#include <pthread.h>
+              ]],
+              [[static struct timespec x; x.tv_sec = x.tv_nsec;]])],
+           [gl_cv_sys_struct_timespec_in_pthread_h=yes],
+           [gl_cv_sys_struct_timespec_in_pthread_h=no])])
+      if test $gl_cv_sys_struct_timespec_in_pthread_h = yes; then
+        PTHREAD_H_DEFINES_STRUCT_TIMESPEC=1
+      else
+        AC_CACHE_CHECK([for struct timespec in <unistd.h>],
+          [gl_cv_sys_struct_timespec_in_unistd_h],
+          [AC_COMPILE_IFELSE(
+             [AC_LANG_PROGRAM(
+                [[#include <unistd.h>
+                ]],
+                [[static struct timespec x; x.tv_sec = x.tv_nsec;]])],
+             [gl_cv_sys_struct_timespec_in_unistd_h=yes],
+             [gl_cv_sys_struct_timespec_in_unistd_h=no])])
+        if test $gl_cv_sys_struct_timespec_in_unistd_h = yes; then
+          UNISTD_H_DEFINES_STRUCT_TIMESPEC=1
+        fi
+      fi
+    fi
+  fi
+  AC_SUBST([TIME_H_DEFINES_STRUCT_TIMESPEC])
+  AC_SUBST([SYS_TIME_H_DEFINES_STRUCT_TIMESPEC])
+  AC_SUBST([PTHREAD_H_DEFINES_STRUCT_TIMESPEC])
+  AC_SUBST([UNISTD_H_DEFINES_STRUCT_TIMESPEC])
+])
+
+AC_DEFUN([gl_TIME_MODULE_INDICATOR],
+[
+  dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
+  AC_REQUIRE([gl_HEADER_TIME_H_DEFAULTS])
+  gl_MODULE_INDICATOR_SET_VARIABLE([$1])
+  dnl Define it also as a C macro, for the benefit of the unit tests.
+  gl_MODULE_INDICATOR_FOR_TESTS([$1])
+])
+
+AC_DEFUN([gl_HEADER_TIME_H_DEFAULTS],
+[
+  GNULIB_CTIME=0;                        AC_SUBST([GNULIB_CTIME])
+  GNULIB_MKTIME=0;                       AC_SUBST([GNULIB_MKTIME])
+  GNULIB_LOCALTIME=0;                    AC_SUBST([GNULIB_LOCALTIME])
+  GNULIB_NANOSLEEP=0;                    AC_SUBST([GNULIB_NANOSLEEP])
+  GNULIB_STRFTIME=0;                     AC_SUBST([GNULIB_STRFTIME])
+  GNULIB_STRPTIME=0;                     AC_SUBST([GNULIB_STRPTIME])
+  GNULIB_TIMEGM=0;                       AC_SUBST([GNULIB_TIMEGM])
+  GNULIB_TIME_R=0;                       AC_SUBST([GNULIB_TIME_R])
+  GNULIB_TIME_RZ=0;                      AC_SUBST([GNULIB_TIME_RZ])
+  GNULIB_TZSET=0;                        AC_SUBST([GNULIB_TZSET])
+  dnl Support Microsoft deprecated alias function names by default.
+  GNULIB_MDA_TZSET=1;                    AC_SUBST([GNULIB_MDA_TZSET])
+  dnl Assume proper GNU behavior unless another module says otherwise.
+  HAVE_DECL_LOCALTIME_R=1;               AC_SUBST([HAVE_DECL_LOCALTIME_R])
+  HAVE_NANOSLEEP=1;                      AC_SUBST([HAVE_NANOSLEEP])
+  HAVE_STRPTIME=1;                       AC_SUBST([HAVE_STRPTIME])
+  HAVE_TIMEGM=1;                         AC_SUBST([HAVE_TIMEGM])
+  dnl Even GNU libc does not have timezone_t yet.
+  HAVE_TIMEZONE_T=0;                     AC_SUBST([HAVE_TIMEZONE_T])
+  dnl If another module says to replace or to not replace, do that.
+  dnl Otherwise, replace only if someone compiles with -DGNULIB_PORTCHECK;
+  dnl this lets maintainers check for portability.
+  REPLACE_CTIME=GNULIB_PORTCHECK;        AC_SUBST([REPLACE_CTIME])
+  REPLACE_LOCALTIME_R=GNULIB_PORTCHECK;  AC_SUBST([REPLACE_LOCALTIME_R])
+  REPLACE_MKTIME=GNULIB_PORTCHECK;       AC_SUBST([REPLACE_MKTIME])
+  REPLACE_NANOSLEEP=GNULIB_PORTCHECK;    AC_SUBST([REPLACE_NANOSLEEP])
+  REPLACE_STRFTIME=GNULIB_PORTCHECK;     AC_SUBST([REPLACE_STRFTIME])
+  REPLACE_TIMEGM=GNULIB_PORTCHECK;       AC_SUBST([REPLACE_TIMEGM])
+  REPLACE_TZSET=GNULIB_PORTCHECK;        AC_SUBST([REPLACE_TZSET])
+
+  dnl Hack so that the time module doesn't depend on the sys_time module.
+  dnl First, default GNULIB_GETTIMEOFDAY to 0 if sys_time is absent.
+  : ${GNULIB_GETTIMEOFDAY=0};            AC_SUBST([GNULIB_GETTIMEOFDAY])
+  dnl Second, it's OK to not use GNULIB_PORTCHECK for REPLACE_GMTIME
+  dnl and REPLACE_LOCALTIME, as portability to Solaris 2.6 and earlier
+  dnl is no longer a big deal.
+  REPLACE_GMTIME=0;                      AC_SUBST([REPLACE_GMTIME])
+  REPLACE_LOCALTIME=0;                   AC_SUBST([REPLACE_LOCALTIME])
+])
diff --git a/m4/time_r.m4 b/m4/time_r.m4
new file mode 100644
index 0000000..0e86d44
--- /dev/null
+++ b/m4/time_r.m4
@@ -0,0 +1,99 @@
+dnl Reentrant time functions: localtime_r, gmtime_r.
+
+dnl Copyright (C) 2003, 2006-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl Written by Paul Eggert.
+
+AC_DEFUN([gl_TIME_R],
+[
+  dnl Persuade glibc and Solaris <time.h> to declare localtime_r.
+  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+
+  AC_REQUIRE([gl_HEADER_TIME_H_DEFAULTS])
+  AC_REQUIRE([AC_C_RESTRICT])
+
+  dnl Some systems don't declare localtime_r() and gmtime_r() if _REENTRANT is
+  dnl not defined.
+  AC_CHECK_DECLS([localtime_r], [], [],
+    [[/* mingw's <time.h> provides the functions asctime_r, ctime_r,
+         gmtime_r, localtime_r only if <unistd.h> or <pthread.h> has
+         been included before.  */
+      #if defined __MINGW32__
+      # include <unistd.h>
+      #endif
+      #include <time.h>
+    ]])
+  if test $ac_cv_have_decl_localtime_r = no; then
+    HAVE_DECL_LOCALTIME_R=0
+  fi
+
+  AC_CHECK_FUNCS_ONCE([localtime_r])
+  if test $ac_cv_func_localtime_r = yes; then
+    HAVE_LOCALTIME_R=1
+    AC_CACHE_CHECK([whether localtime_r is compatible with its POSIX signature],
+      [gl_cv_time_r_posix],
+      [AC_COMPILE_IFELSE(
+         [AC_LANG_PROGRAM(
+            [[/* mingw's <time.h> provides the functions asctime_r, ctime_r,
+                 gmtime_r, localtime_r only if <unistd.h> or <pthread.h> has
+                 been included before.  */
+              #if defined __MINGW32__
+              # include <unistd.h>
+              #endif
+              #include <time.h>
+            ]],
+            [[/* We don't need to append 'restrict's to the argument types,
+                 even though the POSIX signature has the 'restrict's,
+                 since C99 says they can't affect type compatibility.  */
+              struct tm * (*ptr) (time_t const *, struct tm *) = localtime_r;
+              if (ptr) return 0;
+              /* Check the return type is a pointer.
+                 On HP-UX 10 it is 'int'.  */
+              *localtime_r (0, 0);]])
+         ],
+         [gl_cv_time_r_posix=yes],
+         [gl_cv_time_r_posix=no])
+      ])
+    if test $gl_cv_time_r_posix = yes; then
+      REPLACE_LOCALTIME_R=0
+    else
+      REPLACE_LOCALTIME_R=1
+    fi
+  else
+    HAVE_LOCALTIME_R=0
+    dnl On mingw, localtime_r() is defined as an inline function; use through a
+    dnl direct function call works but the use as a function pointer leads to a
+    dnl link error.
+    AC_CACHE_CHECK([whether localtime_r exists as an inline function],
+      [gl_cv_func_localtime_r_inline],
+      [AC_LINK_IFELSE(
+         [AC_LANG_PROGRAM(
+            [[/* mingw's <time.h> provides the functions asctime_r, ctime_r,
+                 gmtime_r, localtime_r only if <unistd.h> or <pthread.h> has
+                 been included before.  */
+              #if defined __MINGW32__
+              # include <unistd.h>
+              #endif
+              #include <time.h>
+            ]],
+            [[time_t a;
+              struct tm r;
+              localtime_r (&a, &r);
+            ]])
+         ],
+         [gl_cv_func_localtime_r_inline=yes],
+         [gl_cv_func_localtime_r_inline=no])
+      ])
+    if test $gl_cv_func_localtime_r_inline = yes; then
+      REPLACE_LOCALTIME_R=1
+    fi
+  fi
+])
+
+# Prerequisites of lib/time_r.c.
+AC_DEFUN([gl_PREREQ_TIME_R], [
+  :
+])
diff --git a/m4/timegm.m4 b/m4/timegm.m4
new file mode 100644
index 0000000..67c0c3b
--- /dev/null
+++ b/m4/timegm.m4
@@ -0,0 +1,26 @@
+# timegm.m4 serial 12
+dnl Copyright (C) 2003, 2007, 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_TIMEGM],
+[
+  AC_REQUIRE([gl_HEADER_TIME_H_DEFAULTS])
+  AC_REQUIRE([gl_FUNC_MKTIME_WORKS])
+  REPLACE_TIMEGM=0
+  AC_CHECK_FUNCS_ONCE([timegm])
+  if test $ac_cv_func_timegm = yes; then
+    if test "$gl_cv_func_working_mktime" != yes; then
+      # Assume that timegm is buggy if mktime is.
+      REPLACE_TIMEGM=1
+    fi
+  else
+    HAVE_TIMEGM=0
+  fi
+])
+
+# Prerequisites of lib/timegm.c.
+AC_DEFUN([gl_PREREQ_TIMEGM], [
+  :
+])
diff --git a/m4/timespec.m4 b/m4/timespec.m4
new file mode 100644
index 0000000..e71628d
--- /dev/null
+++ b/m4/timespec.m4
@@ -0,0 +1,11 @@
+#serial 15
+
+# Copyright (C) 2000-2001, 2003-2007, 2009-2020 Free Software Foundation, Inc.
+
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+dnl From Jim Meyering
+
+AC_DEFUN([gl_TIMESPEC], [:])
diff --git a/m4/tm_gmtoff.m4 b/m4/tm_gmtoff.m4
new file mode 100644
index 0000000..41517d8
--- /dev/null
+++ b/m4/tm_gmtoff.m4
@@ -0,0 +1,14 @@
+# tm_gmtoff.m4 serial 3
+dnl Copyright (C) 2002, 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_TM_GMTOFF],
+[
+ AC_CHECK_MEMBER([struct tm.tm_gmtoff],
+                 [AC_DEFINE([HAVE_TM_GMTOFF], [1],
+                            [Define if struct tm has the tm_gmtoff member.])],
+                 ,
+                 [#include <time.h>])
+])
diff --git a/m4/tmpdir.m4 b/m4/tmpdir.m4
new file mode 100644
index 0000000..ad15a03
--- /dev/null
+++ b/m4/tmpdir.m4
@@ -0,0 +1,9 @@
+# tmpdir.m4 serial 4
+dnl Copyright (C) 2001-2002, 2006, 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+# Prerequisites for lib/tmpdir.c
+
+AC_DEFUN([gt_TMPDIR], [:])
diff --git a/m4/unistd-safer.m4 b/m4/unistd-safer.m4
new file mode 100644
index 0000000..65dfdf2
--- /dev/null
+++ b/m4/unistd-safer.m4
@@ -0,0 +1,10 @@
+#serial 9
+dnl Copyright (C) 2002, 2005-2006, 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_UNISTD_SAFER],
+[
+  AC_CHECK_FUNCS_ONCE([pipe])
+])
diff --git a/m4/unistd_h.m4 b/m4/unistd_h.m4
new file mode 100644
index 0000000..f0db575
--- /dev/null
+++ b/m4/unistd_h.m4
@@ -0,0 +1,251 @@
+# unistd_h.m4 serial 85
+dnl Copyright (C) 2006-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl Written by Simon Josefsson, Bruno Haible.
+
+AC_DEFUN([gl_UNISTD_H],
+[
+  dnl Use AC_REQUIRE here, so that the default behavior below is expanded
+  dnl once only, before all statements that occur in other macros.
+  AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
+
+  gl_CHECK_NEXT_HEADERS([unistd.h])
+  if test $ac_cv_header_unistd_h = yes; then
+    HAVE_UNISTD_H=1
+  else
+    HAVE_UNISTD_H=0
+  fi
+  AC_SUBST([HAVE_UNISTD_H])
+
+  dnl Ensure the type pid_t gets defined.
+  AC_REQUIRE([AC_TYPE_PID_T])
+
+  dnl Determine WINDOWS_64_BIT_OFF_T.
+  AC_REQUIRE([gl_TYPE_OFF_T])
+
+  dnl Check for declarations of anything we want to poison if the
+  dnl corresponding gnulib module is not in use.
+  gl_WARN_ON_USE_PREPARE([[
+#if HAVE_UNISTD_H
+# include <unistd.h>
+#endif
+/* Some systems declare various items in the wrong headers.  */
+#if !(defined __GLIBC__ && !defined __UCLIBC__)
+# include <fcntl.h>
+# include <stdio.h>
+# include <stdlib.h>
+# if defined _WIN32 && ! defined __CYGWIN__
+#  include <io.h>
+# endif
+#endif
+    ]], [access chdir chown copy_file_range dup dup2 dup3 environ euidaccess
+    execl execle execlp execv execve execvp execvpe
+    faccessat fchdir
+    fchownat fdatasync fsync ftruncate getcwd getdomainname getdtablesize
+    getentropy getgroups gethostname getlogin getlogin_r getpagesize getpass
+    getusershell setusershell endusershell
+    group_member isatty lchown link linkat lseek pipe pipe2 pread pwrite
+    readlink readlinkat rmdir sethostname sleep symlink symlinkat
+    truncate ttyname_r unlink unlinkat usleep])
+
+  AC_REQUIRE([AC_C_RESTRICT])
+
+  AC_CHECK_DECLS_ONCE([execvpe])
+  if test $ac_cv_have_decl_execvpe = no; then
+    HAVE_DECL_EXECVPE=0
+  fi
+])
+
+AC_DEFUN([gl_UNISTD_MODULE_INDICATOR],
+[
+  dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
+  AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
+  gl_MODULE_INDICATOR_SET_VARIABLE([$1])
+  dnl Define it also as a C macro, for the benefit of the unit tests.
+  gl_MODULE_INDICATOR_FOR_TESTS([$1])
+])
+
+AC_DEFUN([gl_UNISTD_H_DEFAULTS],
+[
+  GNULIB_ACCESS=0;               AC_SUBST([GNULIB_ACCESS])
+  GNULIB_CHDIR=0;                AC_SUBST([GNULIB_CHDIR])
+  GNULIB_CHOWN=0;                AC_SUBST([GNULIB_CHOWN])
+  GNULIB_CLOSE=0;                AC_SUBST([GNULIB_CLOSE])
+  GNULIB_COPY_FILE_RANGE=0;      AC_SUBST([GNULIB_COPY_FILE_RANGE])
+  GNULIB_DUP=0;                  AC_SUBST([GNULIB_DUP])
+  GNULIB_DUP2=0;                 AC_SUBST([GNULIB_DUP2])
+  GNULIB_DUP3=0;                 AC_SUBST([GNULIB_DUP3])
+  GNULIB_ENVIRON=0;              AC_SUBST([GNULIB_ENVIRON])
+  GNULIB_EUIDACCESS=0;           AC_SUBST([GNULIB_EUIDACCESS])
+  GNULIB_EXECL=0;                AC_SUBST([GNULIB_EXECL])
+  GNULIB_EXECLE=0;               AC_SUBST([GNULIB_EXECLE])
+  GNULIB_EXECLP=0;               AC_SUBST([GNULIB_EXECLP])
+  GNULIB_EXECV=0;                AC_SUBST([GNULIB_EXECV])
+  GNULIB_EXECVE=0;               AC_SUBST([GNULIB_EXECVE])
+  GNULIB_EXECVP=0;               AC_SUBST([GNULIB_EXECVP])
+  GNULIB_EXECVPE=0;              AC_SUBST([GNULIB_EXECVPE])
+  GNULIB_FACCESSAT=0;            AC_SUBST([GNULIB_FACCESSAT])
+  GNULIB_FCHDIR=0;               AC_SUBST([GNULIB_FCHDIR])
+  GNULIB_FCHOWNAT=0;             AC_SUBST([GNULIB_FCHOWNAT])
+  GNULIB_FDATASYNC=0;            AC_SUBST([GNULIB_FDATASYNC])
+  GNULIB_FSYNC=0;                AC_SUBST([GNULIB_FSYNC])
+  GNULIB_FTRUNCATE=0;            AC_SUBST([GNULIB_FTRUNCATE])
+  GNULIB_GETCWD=0;               AC_SUBST([GNULIB_GETCWD])
+  GNULIB_GETDOMAINNAME=0;        AC_SUBST([GNULIB_GETDOMAINNAME])
+  GNULIB_GETDTABLESIZE=0;        AC_SUBST([GNULIB_GETDTABLESIZE])
+  GNULIB_GETENTROPY=0;           AC_SUBST([GNULIB_GETENTROPY])
+  GNULIB_GETGROUPS=0;            AC_SUBST([GNULIB_GETGROUPS])
+  GNULIB_GETHOSTNAME=0;          AC_SUBST([GNULIB_GETHOSTNAME])
+  GNULIB_GETLOGIN=0;             AC_SUBST([GNULIB_GETLOGIN])
+  GNULIB_GETLOGIN_R=0;           AC_SUBST([GNULIB_GETLOGIN_R])
+  GNULIB_GETOPT_POSIX=0;         AC_SUBST([GNULIB_GETOPT_POSIX])
+  GNULIB_GETPAGESIZE=0;          AC_SUBST([GNULIB_GETPAGESIZE])
+  GNULIB_GETPASS=0;              AC_SUBST([GNULIB_GETPASS])
+  GNULIB_GETUSERSHELL=0;         AC_SUBST([GNULIB_GETUSERSHELL])
+  GNULIB_GROUP_MEMBER=0;         AC_SUBST([GNULIB_GROUP_MEMBER])
+  GNULIB_ISATTY=0;               AC_SUBST([GNULIB_ISATTY])
+  GNULIB_LCHOWN=0;               AC_SUBST([GNULIB_LCHOWN])
+  GNULIB_LINK=0;                 AC_SUBST([GNULIB_LINK])
+  GNULIB_LINKAT=0;               AC_SUBST([GNULIB_LINKAT])
+  GNULIB_LSEEK=0;                AC_SUBST([GNULIB_LSEEK])
+  GNULIB_PIPE=0;                 AC_SUBST([GNULIB_PIPE])
+  GNULIB_PIPE2=0;                AC_SUBST([GNULIB_PIPE2])
+  GNULIB_PREAD=0;                AC_SUBST([GNULIB_PREAD])
+  GNULIB_PWRITE=0;               AC_SUBST([GNULIB_PWRITE])
+  GNULIB_READ=0;                 AC_SUBST([GNULIB_READ])
+  GNULIB_READLINK=0;             AC_SUBST([GNULIB_READLINK])
+  GNULIB_READLINKAT=0;           AC_SUBST([GNULIB_READLINKAT])
+  GNULIB_RMDIR=0;                AC_SUBST([GNULIB_RMDIR])
+  GNULIB_SETHOSTNAME=0;          AC_SUBST([GNULIB_SETHOSTNAME])
+  GNULIB_SLEEP=0;                AC_SUBST([GNULIB_SLEEP])
+  GNULIB_SYMLINK=0;              AC_SUBST([GNULIB_SYMLINK])
+  GNULIB_SYMLINKAT=0;            AC_SUBST([GNULIB_SYMLINKAT])
+  GNULIB_TRUNCATE=0;             AC_SUBST([GNULIB_TRUNCATE])
+  GNULIB_TTYNAME_R=0;            AC_SUBST([GNULIB_TTYNAME_R])
+  GNULIB_UNISTD_H_NONBLOCKING=0; AC_SUBST([GNULIB_UNISTD_H_NONBLOCKING])
+  GNULIB_UNISTD_H_SIGPIPE=0;     AC_SUBST([GNULIB_UNISTD_H_SIGPIPE])
+  GNULIB_UNLINK=0;               AC_SUBST([GNULIB_UNLINK])
+  GNULIB_UNLINKAT=0;             AC_SUBST([GNULIB_UNLINKAT])
+  GNULIB_USLEEP=0;               AC_SUBST([GNULIB_USLEEP])
+  GNULIB_WRITE=0;                AC_SUBST([GNULIB_WRITE])
+  dnl Support Microsoft deprecated alias function names by default.
+  GNULIB_MDA_ACCESS=1;           AC_SUBST([GNULIB_MDA_ACCESS])
+  GNULIB_MDA_CHDIR=1;            AC_SUBST([GNULIB_MDA_CHDIR])
+  GNULIB_MDA_CLOSE=1;            AC_SUBST([GNULIB_MDA_CLOSE])
+  GNULIB_MDA_DUP=1;              AC_SUBST([GNULIB_MDA_DUP])
+  GNULIB_MDA_DUP2=1;             AC_SUBST([GNULIB_MDA_DUP2])
+  GNULIB_MDA_EXECL=1;            AC_SUBST([GNULIB_MDA_EXECL])
+  GNULIB_MDA_EXECLE=1;           AC_SUBST([GNULIB_MDA_EXECLE])
+  GNULIB_MDA_EXECLP=1;           AC_SUBST([GNULIB_MDA_EXECLP])
+  GNULIB_MDA_EXECV=1;            AC_SUBST([GNULIB_MDA_EXECV])
+  GNULIB_MDA_EXECVE=1;           AC_SUBST([GNULIB_MDA_EXECVE])
+  GNULIB_MDA_EXECVP=1;           AC_SUBST([GNULIB_MDA_EXECVP])
+  GNULIB_MDA_EXECVPE=1;          AC_SUBST([GNULIB_MDA_EXECVPE])
+  GNULIB_MDA_GETCWD=1;           AC_SUBST([GNULIB_MDA_GETCWD])
+  GNULIB_MDA_GETPID=1;           AC_SUBST([GNULIB_MDA_GETPID])
+  GNULIB_MDA_ISATTY=1;           AC_SUBST([GNULIB_MDA_ISATTY])
+  GNULIB_MDA_LSEEK=1;            AC_SUBST([GNULIB_MDA_LSEEK])
+  GNULIB_MDA_READ=1;             AC_SUBST([GNULIB_MDA_READ])
+  GNULIB_MDA_RMDIR=1;            AC_SUBST([GNULIB_MDA_RMDIR])
+  GNULIB_MDA_SWAB=1;             AC_SUBST([GNULIB_MDA_SWAB])
+  GNULIB_MDA_UNLINK=1;           AC_SUBST([GNULIB_MDA_UNLINK])
+  GNULIB_MDA_WRITE=1;            AC_SUBST([GNULIB_MDA_WRITE])
+  dnl Assume proper GNU behavior unless another module says otherwise.
+  HAVE_CHOWN=1;           AC_SUBST([HAVE_CHOWN])
+  HAVE_COPY_FILE_RANGE=1; AC_SUBST([HAVE_COPY_FILE_RANGE])
+  HAVE_DUP3=1;            AC_SUBST([HAVE_DUP3])
+  HAVE_EUIDACCESS=1;      AC_SUBST([HAVE_EUIDACCESS])
+  HAVE_EXECVPE=1;         AC_SUBST([HAVE_EXECVPE])
+  HAVE_FACCESSAT=1;       AC_SUBST([HAVE_FACCESSAT])
+  HAVE_FCHDIR=1;          AC_SUBST([HAVE_FCHDIR])
+  HAVE_FCHOWNAT=1;        AC_SUBST([HAVE_FCHOWNAT])
+  HAVE_FDATASYNC=1;       AC_SUBST([HAVE_FDATASYNC])
+  HAVE_FSYNC=1;           AC_SUBST([HAVE_FSYNC])
+  HAVE_FTRUNCATE=1;       AC_SUBST([HAVE_FTRUNCATE])
+  HAVE_GETDTABLESIZE=1;   AC_SUBST([HAVE_GETDTABLESIZE])
+  HAVE_GETENTROPY=1;      AC_SUBST([HAVE_GETENTROPY])
+  HAVE_GETGROUPS=1;       AC_SUBST([HAVE_GETGROUPS])
+  HAVE_GETHOSTNAME=1;     AC_SUBST([HAVE_GETHOSTNAME])
+  HAVE_GETLOGIN=1;        AC_SUBST([HAVE_GETLOGIN])
+  HAVE_GETPAGESIZE=1;     AC_SUBST([HAVE_GETPAGESIZE])
+  HAVE_GETPASS=1;         AC_SUBST([HAVE_GETPASS])
+  HAVE_GROUP_MEMBER=1;    AC_SUBST([HAVE_GROUP_MEMBER])
+  HAVE_LCHOWN=1;          AC_SUBST([HAVE_LCHOWN])
+  HAVE_LINK=1;            AC_SUBST([HAVE_LINK])
+  HAVE_LINKAT=1;          AC_SUBST([HAVE_LINKAT])
+  HAVE_PIPE=1;            AC_SUBST([HAVE_PIPE])
+  HAVE_PIPE2=1;           AC_SUBST([HAVE_PIPE2])
+  HAVE_PREAD=1;           AC_SUBST([HAVE_PREAD])
+  HAVE_PWRITE=1;          AC_SUBST([HAVE_PWRITE])
+  HAVE_READLINK=1;        AC_SUBST([HAVE_READLINK])
+  HAVE_READLINKAT=1;      AC_SUBST([HAVE_READLINKAT])
+  HAVE_SETHOSTNAME=1;     AC_SUBST([HAVE_SETHOSTNAME])
+  HAVE_SLEEP=1;           AC_SUBST([HAVE_SLEEP])
+  HAVE_SYMLINK=1;         AC_SUBST([HAVE_SYMLINK])
+  HAVE_SYMLINKAT=1;       AC_SUBST([HAVE_SYMLINKAT])
+  HAVE_UNLINKAT=1;        AC_SUBST([HAVE_UNLINKAT])
+  HAVE_USLEEP=1;          AC_SUBST([HAVE_USLEEP])
+  HAVE_DECL_ENVIRON=1;    AC_SUBST([HAVE_DECL_ENVIRON])
+  HAVE_DECL_EXECVPE=1;    AC_SUBST([HAVE_DECL_EXECVPE])
+  HAVE_DECL_FCHDIR=1;     AC_SUBST([HAVE_DECL_FCHDIR])
+  HAVE_DECL_FDATASYNC=1;  AC_SUBST([HAVE_DECL_FDATASYNC])
+  HAVE_DECL_GETDOMAINNAME=1; AC_SUBST([HAVE_DECL_GETDOMAINNAME])
+  HAVE_DECL_GETLOGIN=1;   AC_SUBST([HAVE_DECL_GETLOGIN])
+  HAVE_DECL_GETLOGIN_R=1; AC_SUBST([HAVE_DECL_GETLOGIN_R])
+  HAVE_DECL_GETPAGESIZE=1; AC_SUBST([HAVE_DECL_GETPAGESIZE])
+  HAVE_DECL_GETUSERSHELL=1; AC_SUBST([HAVE_DECL_GETUSERSHELL])
+  HAVE_DECL_SETHOSTNAME=1; AC_SUBST([HAVE_DECL_SETHOSTNAME])
+  HAVE_DECL_TRUNCATE=1;   AC_SUBST([HAVE_DECL_TRUNCATE])
+  HAVE_DECL_TTYNAME_R=1;  AC_SUBST([HAVE_DECL_TTYNAME_R])
+  HAVE_OS_H=0;            AC_SUBST([HAVE_OS_H])
+  HAVE_SYS_PARAM_H=0;     AC_SUBST([HAVE_SYS_PARAM_H])
+  REPLACE_ACCESS=0;       AC_SUBST([REPLACE_ACCESS])
+  REPLACE_CHOWN=0;        AC_SUBST([REPLACE_CHOWN])
+  REPLACE_CLOSE=0;        AC_SUBST([REPLACE_CLOSE])
+  REPLACE_DUP=0;          AC_SUBST([REPLACE_DUP])
+  REPLACE_DUP2=0;         AC_SUBST([REPLACE_DUP2])
+  REPLACE_EXECL=0;        AC_SUBST([REPLACE_EXECL])
+  REPLACE_EXECLE=0;       AC_SUBST([REPLACE_EXECLE])
+  REPLACE_EXECLP=0;       AC_SUBST([REPLACE_EXECLP])
+  REPLACE_EXECV=0;        AC_SUBST([REPLACE_EXECV])
+  REPLACE_EXECVE=0;       AC_SUBST([REPLACE_EXECVE])
+  REPLACE_EXECVP=0;       AC_SUBST([REPLACE_EXECVP])
+  REPLACE_EXECVPE=0;      AC_SUBST([REPLACE_EXECVPE])
+  REPLACE_FACCESSAT=0;    AC_SUBST([REPLACE_FACCESSAT])
+  REPLACE_FCHOWNAT=0;     AC_SUBST([REPLACE_FCHOWNAT])
+  REPLACE_FTRUNCATE=0;    AC_SUBST([REPLACE_FTRUNCATE])
+  REPLACE_GETCWD=0;       AC_SUBST([REPLACE_GETCWD])
+  REPLACE_GETDOMAINNAME=0; AC_SUBST([REPLACE_GETDOMAINNAME])
+  REPLACE_GETDTABLESIZE=0; AC_SUBST([REPLACE_GETDTABLESIZE])
+  REPLACE_GETLOGIN_R=0;   AC_SUBST([REPLACE_GETLOGIN_R])
+  REPLACE_GETGROUPS=0;    AC_SUBST([REPLACE_GETGROUPS])
+  REPLACE_GETPAGESIZE=0;  AC_SUBST([REPLACE_GETPAGESIZE])
+  REPLACE_GETPASS=0;      AC_SUBST([REPLACE_GETPASS])
+  REPLACE_ISATTY=0;       AC_SUBST([REPLACE_ISATTY])
+  REPLACE_LCHOWN=0;       AC_SUBST([REPLACE_LCHOWN])
+  REPLACE_LINK=0;         AC_SUBST([REPLACE_LINK])
+  REPLACE_LINKAT=0;       AC_SUBST([REPLACE_LINKAT])
+  REPLACE_LSEEK=0;        AC_SUBST([REPLACE_LSEEK])
+  REPLACE_PREAD=0;        AC_SUBST([REPLACE_PREAD])
+  REPLACE_PWRITE=0;       AC_SUBST([REPLACE_PWRITE])
+  REPLACE_READ=0;         AC_SUBST([REPLACE_READ])
+  REPLACE_READLINK=0;     AC_SUBST([REPLACE_READLINK])
+  REPLACE_READLINKAT=0;   AC_SUBST([REPLACE_READLINKAT])
+  REPLACE_RMDIR=0;        AC_SUBST([REPLACE_RMDIR])
+  REPLACE_SLEEP=0;        AC_SUBST([REPLACE_SLEEP])
+  REPLACE_SYMLINK=0;      AC_SUBST([REPLACE_SYMLINK])
+  REPLACE_SYMLINKAT=0;    AC_SUBST([REPLACE_SYMLINKAT])
+  REPLACE_TRUNCATE=0;     AC_SUBST([REPLACE_TRUNCATE])
+  REPLACE_TTYNAME_R=0;    AC_SUBST([REPLACE_TTYNAME_R])
+  REPLACE_UNLINK=0;       AC_SUBST([REPLACE_UNLINK])
+  REPLACE_UNLINKAT=0;     AC_SUBST([REPLACE_UNLINKAT])
+  REPLACE_USLEEP=0;       AC_SUBST([REPLACE_USLEEP])
+  REPLACE_WRITE=0;        AC_SUBST([REPLACE_WRITE])
+  UNISTD_H_HAVE_SYS_RANDOM_H=0; AC_SUBST([UNISTD_H_HAVE_SYS_RANDOM_H])
+  UNISTD_H_HAVE_WINSOCK2_H=0; AC_SUBST([UNISTD_H_HAVE_WINSOCK2_H])
+  UNISTD_H_HAVE_WINSOCK2_H_AND_USE_SOCKETS=0;
+                           AC_SUBST([UNISTD_H_HAVE_WINSOCK2_H_AND_USE_SOCKETS])
+])
diff --git a/m4/unlink.m4 b/m4/unlink.m4
new file mode 100644
index 0000000..69d8ba5
--- /dev/null
+++ b/m4/unlink.m4
@@ -0,0 +1,135 @@
+# unlink.m4 serial 15
+dnl Copyright (C) 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_UNLINK],
+[
+  AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  AC_CHECK_HEADERS_ONCE([unistd.h])
+
+  dnl Detect FreeBSD 7.2, AIX 7.1, Solaris 9 bug.
+  AC_CACHE_CHECK([whether unlink honors trailing slashes],
+    [gl_cv_func_unlink_honors_slashes],
+    [touch conftest.file
+     # Assume that if we have lstat, we can also check symlinks.
+     if test $ac_cv_func_lstat = yes; then
+       ln -s conftest.file conftest.lnk
+     fi
+     AC_RUN_IFELSE(
+       [AC_LANG_PROGRAM(
+         [[#if HAVE_UNISTD_H
+           # include <unistd.h>
+           #else /* on Windows with MSVC */
+           # include <io.h>
+           #endif
+           #include <errno.h>
+         ]GL_MDA_DEFINES],
+         [[int result = 0;
+           if (!unlink ("conftest.file/"))
+             result |= 1;
+           else if (errno != ENOTDIR)
+             result |= 2;
+#if HAVE_LSTAT
+           if (!unlink ("conftest.lnk/"))
+             result |= 4;
+           else if (errno != ENOTDIR)
+             result |= 8;
+#endif
+           return result;
+         ]])],
+      [gl_cv_func_unlink_honors_slashes=yes],
+      [gl_cv_func_unlink_honors_slashes=no],
+      [case "$host_os" in
+                          # Guess yes on Linux systems.
+         linux-* | linux) gl_cv_func_unlink_honors_slashes="guessing yes" ;;
+                          # Guess yes on glibc systems.
+         *-gnu*)          gl_cv_func_unlink_honors_slashes="guessing yes" ;;
+                          # Guess no on native Windows.
+         mingw*)          gl_cv_func_unlink_honors_slashes="guessing no" ;;
+                          # If we don't know, obey --enable-cross-guesses.
+         *)               gl_cv_func_unlink_honors_slashes="$gl_cross_guess_normal" ;;
+       esac
+      ])
+     rm -f conftest.file conftest.lnk])
+  case "$gl_cv_func_unlink_honors_slashes" in
+    *no)
+      REPLACE_UNLINK=1
+      ;;
+  esac
+
+  dnl Detect Mac OS X 10.5.6 bug: On read-write HFS mounts, unlink("..") or
+  dnl unlink("../..") succeeds without doing anything.
+  AC_CACHE_CHECK([whether unlink of a parent directory fails as it should],
+    [gl_cv_func_unlink_parent_fails],
+    [case "$host_os" in
+       darwin*)
+         dnl Try to unlink a subdirectory of /tmp, because /tmp is usually on a
+         dnl HFS mount on Mac OS X. Use a subdirectory, owned by the current
+         dnl user, because otherwise unlink() may fail due to permissions
+         dnl reasons, and because when running as root we don't want to risk
+         dnl destroying the entire /tmp.
+         if {
+              # Use the mktemp program if available. If not available, hide the error
+              # message.
+              tmp=`(umask 077 && mktemp -d /tmp/gtXXXXXX) 2>/dev/null` &&
+              test -n "$tmp" && test -d "$tmp"
+            } ||
+            {
+              # Use a simple mkdir command. It is guaranteed to fail if the directory
+              # already exists.  $RANDOM is bash specific and expands to empty in shells
+              # other than bash, ksh and zsh.  Its use does not increase security;
+              # rather, it minimizes the probability of failure in a very cluttered /tmp
+              # directory.
+              tmp=/tmp/gt$$-$RANDOM
+              (umask 077 && mkdir "$tmp")
+            }; then
+           mkdir "$tmp/subdir"
+           GL_SUBDIR_FOR_UNLINK="$tmp/subdir"
+           export GL_SUBDIR_FOR_UNLINK
+           AC_RUN_IFELSE(
+             [AC_LANG_SOURCE([[
+                #include <stdlib.h>
+                #if HAVE_UNISTD_H
+                # include <unistd.h>
+                #else /* on Windows with MSVC */
+                # include <direct.h>
+                # include <io.h>
+                #endif
+                ]GL_MDA_DEFINES[
+                int main ()
+                {
+                  int result = 0;
+                  if (chdir (getenv ("GL_SUBDIR_FOR_UNLINK")) != 0)
+                    result |= 1;
+                  else if (unlink ("..") == 0)
+                    result |= 2;
+                  return result;
+                }
+              ]])],
+             [gl_cv_func_unlink_parent_fails=yes],
+             [gl_cv_func_unlink_parent_fails=no],
+             [# If we don't know, obey --enable-cross-guesses.
+              gl_cv_func_unlink_parent_fails="$gl_cross_guess_normal"
+             ])
+           unset GL_SUBDIR_FOR_UNLINK
+           rm -rf "$tmp"
+         else
+           gl_cv_func_unlink_parent_fails="guessing no"
+         fi
+         ;;
+       *)
+         gl_cv_func_unlink_parent_fails="guessing yes"
+         ;;
+     esac
+    ])
+  case "$gl_cv_func_unlink_parent_fails" in
+    *no)
+      REPLACE_UNLINK=1
+      AC_DEFINE([UNLINK_PARENT_BUG], [1],
+        [Define to 1 if unlink() on a parent directory may succeed])
+      ;;
+  esac
+])
diff --git a/m4/unlocked-io.m4 b/m4/unlocked-io.m4
new file mode 100644
index 0000000..38658e6
--- /dev/null
+++ b/m4/unlocked-io.m4
@@ -0,0 +1,41 @@
+# unlocked-io.m4 serial 15
+
+# Copyright (C) 1998-2006, 2009-2020 Free Software Foundation, Inc.
+#
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+dnl From Jim Meyering.
+dnl
+dnl See if the glibc *_unlocked I/O macros or functions are available.
+dnl Use only those *_unlocked macros or functions that are declared
+dnl (because some of them were declared in Solaris 2.5.1 but were removed
+dnl in Solaris 2.6, whereas we want binaries built on Solaris 2.5.1 to run
+dnl on Solaris 2.6).
+
+AC_DEFUN([gl_FUNC_GLIBC_UNLOCKED_IO],
+[
+  AC_DEFINE([USE_UNLOCKED_IO], [1],
+    [Define to 1 if you want getc etc. to use unlocked I/O if available.
+     Unlocked I/O can improve performance in unithreaded apps,
+     but it is not safe for multithreaded apps.])
+
+  dnl Persuade glibc and Solaris <stdio.h> to declare
+  dnl fgets_unlocked(), fputs_unlocked() etc.
+  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+
+  AC_CHECK_DECLS_ONCE([clearerr_unlocked])
+  AC_CHECK_DECLS_ONCE([feof_unlocked])
+  AC_CHECK_DECLS_ONCE([ferror_unlocked])
+  AC_CHECK_DECLS_ONCE([fflush_unlocked])
+  AC_CHECK_DECLS_ONCE([fgets_unlocked])
+  AC_CHECK_DECLS_ONCE([fputc_unlocked])
+  AC_CHECK_DECLS_ONCE([fputs_unlocked])
+  AC_CHECK_DECLS_ONCE([fread_unlocked])
+  AC_CHECK_DECLS_ONCE([fwrite_unlocked])
+  AC_CHECK_DECLS_ONCE([getc_unlocked])
+  AC_CHECK_DECLS_ONCE([getchar_unlocked])
+  AC_CHECK_DECLS_ONCE([putc_unlocked])
+  AC_CHECK_DECLS_ONCE([putchar_unlocked])
+])
diff --git a/m4/utime.m4 b/m4/utime.m4
new file mode 100644
index 0000000..3d2e13c
--- /dev/null
+++ b/m4/utime.m4
@@ -0,0 +1,76 @@
+# utime.m4 serial 3
+dnl Copyright (C) 2017-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_UTIME],
+[
+  AC_REQUIRE([gl_UTIME_H_DEFAULTS])
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  AC_CHECK_FUNCS_ONCE([lstat])
+  case "$host_os" in
+    mingw*)
+      dnl On this platform, the original utime() or _utime() produces
+      dnl timestamps that are affected by the time zone.
+      dnl Use the function name 'rpl_utime' always, in order to avoid a
+      dnl possible conflict with the function name 'utime' from oldnames.lib
+      dnl (MSVC) or liboldnames.a (mingw).
+      REPLACE_UTIME=1
+      ;;
+    *)
+      AC_CHECK_FUNCS([utime])
+      if test $ac_cv_func_utime = no; then
+        HAVE_UTIME=0
+      else
+        dnl On macOS 10.13, utime("link-to-file/", NULL) mistakenly succeeds.
+        AC_CACHE_CHECK([whether utime handles trailing slashes on files],
+          [gl_cv_func_utime_file_slash],
+          [touch conftest.tmp
+           # Assume that if we have lstat, we can also check symlinks.
+           if test $ac_cv_func_lstat = yes; then
+             ln -s conftest.tmp conftest.lnk
+           fi
+           AC_RUN_IFELSE(
+             [AC_LANG_PROGRAM(
+               [[#include <stddef.h>
+                 #include <time.h>
+               ]],
+               [[int result = 0;
+                 if (!utime ("conftest.tmp/", NULL))
+                   result |= 1;
+                 #if HAVE_LSTAT
+                 if (!utime ("conftest.lnk/", NULL))
+                   result |= 2;
+                 #endif
+                 return result;
+               ]])],
+             [gl_cv_func_utime_file_slash=yes],
+             [gl_cv_func_utime_file_slash=no],
+             [case "$host_os" in
+                                 # Guess yes on Linux systems.
+                linux-* | linux) gl_cv_func_utime_file_slash="guessing yes" ;;
+                                 # Guess yes on glibc systems.
+                *-gnu* | gnu*)   gl_cv_func_utime_file_slash="guessing yes" ;;
+                                 # Guess no on macOS.
+                darwin*)         gl_cv_func_utime_file_slash="guessing no" ;;
+                                 # If we don't know, obey --enable-cross-guesses.
+                *)               gl_cv_func_utime_file_slash="$gl_cross_guess_normal" ;;
+              esac
+             ])
+           rm -f conftest.tmp conftest.lnk
+          ])
+        case $gl_cv_func_stat_file_slash in
+          *no)
+            REPLACE_UTIME=1
+            AC_DEFINE([REPLACE_FUNC_UTIME_FILE], [1],
+              [Define to 1 if utime needs help when passed a file name with a trailing slash])
+            ;;
+        esac
+      fi
+      ;;
+  esac
+])
+
+# Prerequisites of lib/utime.c.
+AC_DEFUN([gl_PREREQ_UTIME], [:])
diff --git a/m4/utime_h.m4 b/m4/utime_h.m4
new file mode 100644
index 0000000..b715a53
--- /dev/null
+++ b/m4/utime_h.m4
@@ -0,0 +1,48 @@
+# utime_h.m4 serial 5
+dnl Copyright (C) 2017-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl From Bruno Haible.
+
+AC_DEFUN([gl_UTIME_H],
+[
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  AC_REQUIRE([gl_UTIME_H_DEFAULTS])
+  m4_ifdef([gl_ANSI_CXX], [AC_REQUIRE([gl_ANSI_CXX])])
+  AC_CHECK_HEADERS_ONCE([utime.h])
+  gl_CHECK_NEXT_HEADERS([utime.h])
+
+  if test $ac_cv_header_utime_h = yes; then
+    HAVE_UTIME_H=1
+  else
+    HAVE_UTIME_H=0
+  fi
+  AC_SUBST([HAVE_UTIME_H])
+
+  dnl Check for declarations of anything we want to poison if the
+  dnl corresponding gnulib module is not in use.
+  gl_WARN_ON_USE_PREPARE([[#include <utime.h>
+    ]],
+    [utime])
+])
+
+AC_DEFUN([gl_UTIME_MODULE_INDICATOR],
+[
+  dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
+  AC_REQUIRE([gl_UTIME_H_DEFAULTS])
+  gl_MODULE_INDICATOR_SET_VARIABLE([$1])
+  dnl Define it also as a C macro, for the benefit of the unit tests.
+  gl_MODULE_INDICATOR_FOR_TESTS([$1])
+])
+
+AC_DEFUN([gl_UTIME_H_DEFAULTS],
+[
+  GNULIB_UTIME=0;            AC_SUBST([GNULIB_UTIME])
+  dnl Support Microsoft deprecated alias function names by default.
+  GNULIB_MDA_UTIME=1;        AC_SUBST([GNULIB_MDA_UTIME])
+  dnl Assume POSIX behavior unless another module says otherwise.
+  HAVE_UTIME=1;              AC_SUBST([HAVE_UTIME])
+  REPLACE_UTIME=0;           AC_SUBST([REPLACE_UTIME])
+])
diff --git a/m4/utimens.m4 b/m4/utimens.m4
new file mode 100644
index 0000000..3d31085
--- /dev/null
+++ b/m4/utimens.m4
@@ -0,0 +1,52 @@
+dnl Copyright (C) 2003-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl serial 11
+
+AC_DEFUN([gl_UTIMENS],
+[
+  dnl Prerequisites of lib/utimens.c.
+  AC_REQUIRE([gl_FUNC_UTIMES])
+  AC_REQUIRE([gl_CHECK_TYPE_STRUCT_TIMESPEC])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_CHECK_FUNCS_ONCE([futimes futimesat futimens utimensat lutimes])
+
+  if test $ac_cv_func_futimens = no && test $ac_cv_func_futimesat = yes; then
+    dnl FreeBSD 8.0-rc2 mishandles futimesat(fd,NULL,time).  It is not
+    dnl standardized, but Solaris implemented it first and uses it as
+    dnl its only means to set fd time.
+    AC_CACHE_CHECK([whether futimesat handles NULL file],
+      [gl_cv_func_futimesat_works],
+      [touch conftest.file
+       AC_RUN_IFELSE([AC_LANG_PROGRAM([[
+#include <stddef.h>
+#include <sys/times.h>
+#include <fcntl.h>
+]GL_MDA_DEFINES],
+        [[int fd = open ("conftest.file", O_RDWR);
+          if (fd < 0) return 1;
+          if (futimesat (fd, NULL, NULL)) return 2;
+        ]])],
+        [gl_cv_func_futimesat_works=yes],
+        [gl_cv_func_futimesat_works=no],
+        [case "$host_os" in
+                            # Guess yes on Linux systems.
+           linux-* | linux) gl_cv_func_futimesat_works="guessing yes" ;;
+                            # Guess yes on glibc systems.
+           *-gnu*)          gl_cv_func_futimesat_works="guessing yes" ;;
+                            # If we don't know, obey --enable-cross-guesses.
+           *)               gl_cv_func_futimesat_works="$gl_cross_guess_normal" ;;
+         esac
+        ])
+      rm -f conftest.file])
+    case "$gl_cv_func_futimesat_works" in
+      *yes) ;;
+      *)
+        AC_DEFINE([FUTIMESAT_NULL_BUG], [1],
+          [Define to 1 if futimesat mishandles a NULL file name.])
+        ;;
+    esac
+  fi
+])
diff --git a/m4/utimes.m4 b/m4/utimes.m4
new file mode 100644
index 0000000..877bfd2
--- /dev/null
+++ b/m4/utimes.m4
@@ -0,0 +1,161 @@
+# Detect some bugs in glibc's implementation of utimes.
+# serial 8
+
+dnl Copyright (C) 2003-2005, 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+# See if we need to work around bugs in glibc's implementation of
+# utimes from 2003-07-12 to 2003-09-17.
+# First, there was a bug that would make utimes set mtime
+# and atime to zero (1970-01-01) unconditionally.
+# Then, there was code to round rather than truncate.
+# Then, there was an implementation (sparc64, Linux-2.4.28, glibc-2.3.3)
+# that didn't honor the NULL-means-set-to-current-time semantics.
+# Finally, there was also a version of utimes that failed on read-only
+# files, while utime worked fine (linux-2.2.20, glibc-2.2.5).
+#
+# From Jim Meyering, with suggestions from Paul Eggert.
+
+AC_DEFUN([gl_FUNC_UTIMES],
+[
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_CACHE_CHECK([whether the utimes function works],
+                 [gl_cv_func_working_utimes],
+    [AC_RUN_IFELSE([AC_LANG_SOURCE([[
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <sys/time.h>
+#include <time.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <utime.h>
+#include <errno.h>
+]GL_MDA_DEFINES[
+
+static int
+inorder (time_t a, time_t b, time_t c)
+{
+  return a <= b && b <= c;
+}
+
+int
+main ()
+{
+  int result = 0;
+  char const *file = "conftest.utimes";
+  /* On OS/2, file timestamps must be on or after 1980 in local time,
+     with an even number of seconds.  */
+  static struct timeval timeval[2] = {{315620000 + 10, 10},
+                                      {315620000 + 1000000, 999998}};
+
+  /* Test whether utimes() essentially works.  */
+  {
+    struct stat sbuf;
+    FILE *f = fopen (file, "w");
+    if (f == NULL)
+      result |= 1;
+    else if (fclose (f) != 0)
+      result |= 1;
+    else if (utimes (file, timeval) != 0)
+      result |= 2;
+    else if (lstat (file, &sbuf) != 0)
+      result |= 1;
+    else if (!(sbuf.st_atime == timeval[0].tv_sec
+               && sbuf.st_mtime == timeval[1].tv_sec))
+      result |= 4;
+    if (unlink (file) != 0)
+      result |= 1;
+  }
+
+  /* Test whether utimes() with a NULL argument sets the file's timestamp
+     to the current time.  Use 'fstat' as well as 'time' to
+     determine the "current" time, to accommodate NFS file systems
+     if there is a time skew between the host and the NFS server.  */
+  {
+    int fd = open (file, O_WRONLY|O_CREAT, 0644);
+    if (fd < 0)
+      result |= 1;
+    else
+      {
+        time_t t0, t2;
+        struct stat st0, st1, st2;
+        if (time (&t0) == (time_t) -1)
+          result |= 1;
+        else if (fstat (fd, &st0) != 0)
+          result |= 1;
+        else if (utimes (file, timeval) != 0
+                 && (errno != EACCES
+                     /* OS/2 kLIBC utimes fails on opened files.  */
+                     || close (fd) != 0
+                     || utimes (file, timeval) != 0
+                     || (fd = open (file, O_WRONLY)) < 0))
+          result |= 2;
+        else if (utimes (file, NULL) != 0
+                 && (errno != EACCES
+                     /* OS/2 kLIBC utimes fails on opened files.  */
+                     || close (fd) != 0
+                     || utimes (file, NULL) != 0
+                     || (fd = open (file, O_WRONLY)) < 0))
+          result |= 8;
+        else if (fstat (fd, &st1) != 0)
+          result |= 1;
+        else if (write (fd, "\n", 1) != 1)
+          result |= 1;
+        else if (fstat (fd, &st2) != 0)
+          result |= 1;
+        else if (time (&t2) == (time_t) -1)
+          result |= 1;
+        else
+          {
+            int m_ok_POSIX = inorder (t0, st1.st_mtime, t2);
+            int m_ok_NFS = inorder (st0.st_mtime, st1.st_mtime, st2.st_mtime);
+            if (! (st1.st_atime == st1.st_mtime))
+              result |= 16;
+            if (! (m_ok_POSIX || m_ok_NFS))
+              result |= 32;
+          }
+        if (close (fd) != 0)
+          result |= 1;
+      }
+    if (unlink (file) != 0)
+      result |= 1;
+  }
+
+  /* Test whether utimes() with a NULL argument works on read-only files.  */
+  {
+    int fd = open (file, O_WRONLY|O_CREAT, 0444);
+    if (fd < 0)
+      result |= 1;
+    else if (close (fd) != 0)
+      result |= 1;
+    else if (utimes (file, NULL) != 0)
+      result |= 64;
+    if (unlink (file) != 0)
+      result |= 1;
+  }
+
+  return result;
+}
+  ]])],
+       [gl_cv_func_working_utimes=yes],
+       [gl_cv_func_working_utimes=no],
+       [case "$host_os" in
+                   # Guess yes on musl systems.
+          *-musl*) gl_cv_func_working_utimes="guessing yes" ;;
+                   # Guess no on native Windows.
+          mingw*)  gl_cv_func_working_utimes="guessing no" ;;
+          *)       gl_cv_func_working_utimes="$gl_cross_guess_normal" ;;
+        esac
+       ])
+    ])
+
+  case "$gl_cv_func_working_utimes" in
+    *yes)
+      AC_DEFINE([HAVE_WORKING_UTIMES], [1], [Define if utimes works properly.])
+      ;;
+  esac
+])
diff --git a/m4/vasnprintf.m4 b/m4/vasnprintf.m4
new file mode 100644
index 0000000..43f070e
--- /dev/null
+++ b/m4/vasnprintf.m4
@@ -0,0 +1,298 @@
+# vasnprintf.m4 serial 38
+dnl Copyright (C) 2002-2004, 2006-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_VASNPRINTF],
+[
+  AC_CHECK_FUNCS_ONCE([vasnprintf])
+  if test $ac_cv_func_vasnprintf = no; then
+    gl_REPLACE_VASNPRINTF
+  fi
+])
+
+AC_DEFUN([gl_REPLACE_VASNPRINTF],
+[
+  AC_CHECK_FUNCS_ONCE([vasnprintf])
+  AC_LIBOBJ([vasnprintf])
+  AC_LIBOBJ([printf-args])
+  AC_LIBOBJ([printf-parse])
+  AC_LIBOBJ([asnprintf])
+  if test $ac_cv_func_vasnprintf = yes; then
+    AC_DEFINE([REPLACE_VASNPRINTF], [1],
+      [Define if vasnprintf exists but is overridden by gnulib.])
+  fi
+  gl_PREREQ_PRINTF_ARGS
+  gl_PREREQ_PRINTF_PARSE
+  gl_PREREQ_VASNPRINTF
+  gl_PREREQ_ASNPRINTF
+])
+
+# Prerequisites of lib/printf-args.h, lib/printf-args.c.
+AC_DEFUN([gl_PREREQ_PRINTF_ARGS],
+[
+  AC_REQUIRE([gt_TYPE_WCHAR_T])
+  AC_REQUIRE([gt_TYPE_WINT_T])
+])
+
+# Prerequisites of lib/printf-parse.h, lib/printf-parse.c.
+AC_DEFUN([gl_PREREQ_PRINTF_PARSE],
+[
+  AC_REQUIRE([gl_FEATURES_H])
+  AC_REQUIRE([gt_TYPE_WCHAR_T])
+  AC_REQUIRE([gt_TYPE_WINT_T])
+  AC_REQUIRE([AC_TYPE_SIZE_T])
+  AC_CHECK_TYPE([ptrdiff_t], ,
+    [AC_DEFINE([ptrdiff_t], [long],
+       [Define as the type of the result of subtracting two pointers, if the system doesn't define it.])
+    ])
+  AC_REQUIRE([gt_AC_TYPE_INTMAX_T])
+])
+
+# Prerequisites of lib/vasnprintf.c.
+AC_DEFUN_ONCE([gl_PREREQ_VASNPRINTF],
+[
+  AC_REQUIRE([AC_FUNC_ALLOCA])
+  AC_REQUIRE([gt_TYPE_WCHAR_T])
+  AC_REQUIRE([gt_TYPE_WINT_T])
+  AC_CHECK_FUNCS([snprintf strnlen wcslen wcsnlen mbrtowc wcrtomb])
+  dnl Use the _snprintf function only if it is declared (because on NetBSD it
+  dnl is defined as a weak alias of snprintf; we prefer to use the latter).
+  AC_CHECK_DECLS([_snprintf], , , [[#include <stdio.h>]])
+  dnl Knowing DBL_EXPBIT0_WORD and DBL_EXPBIT0_BIT enables an optimization
+  dnl in the code for NEED_PRINTF_LONG_DOUBLE || NEED_PRINTF_DOUBLE.
+  AC_REQUIRE([gl_DOUBLE_EXPONENT_LOCATION])
+  dnl We can avoid a lot of code by assuming that snprintf's return value
+  dnl conforms to ISO C99. So check that.
+  AC_REQUIRE([gl_SNPRINTF_RETVAL_C99])
+  case "$gl_cv_func_snprintf_retval_c99" in
+    *yes)
+      AC_DEFINE([HAVE_SNPRINTF_RETVAL_C99], [1],
+        [Define if the return value of the snprintf function is the number of
+         of bytes (excluding the terminating NUL) that would have been produced
+         if the buffer had been large enough.])
+      ;;
+  esac
+  dnl Additionally, the use of %n can be eliminated by assuming that snprintf
+  dnl always produces NUL-terminated strings (no truncation).
+  AC_REQUIRE([gl_SNPRINTF_TRUNCATION_C99])
+  case "$gl_cv_func_snprintf_truncation_c99" in
+    *yes)
+      AC_DEFINE([HAVE_SNPRINTF_TRUNCATION_C99], [1],
+        [Define if the string produced by the snprintf function is always NUL
+         terminated.])
+      ;;
+  esac
+])
+
+# Extra prerequisites of lib/vasnprintf.c for supporting 'long double'
+# arguments.
+AC_DEFUN_ONCE([gl_PREREQ_VASNPRINTF_LONG_DOUBLE],
+[
+  AC_REQUIRE([gl_PRINTF_LONG_DOUBLE])
+  case "$gl_cv_func_printf_long_double" in
+    *yes)
+      ;;
+    *)
+      AC_DEFINE([NEED_PRINTF_LONG_DOUBLE], [1],
+        [Define if the vasnprintf implementation needs special code for
+         'long double' arguments.])
+      ;;
+  esac
+])
+
+# Extra prerequisites of lib/vasnprintf.c for supporting infinite 'double'
+# arguments.
+AC_DEFUN([gl_PREREQ_VASNPRINTF_INFINITE_DOUBLE],
+[
+  AC_REQUIRE([gl_PRINTF_INFINITE])
+  case "$gl_cv_func_printf_infinite" in
+    *yes)
+      ;;
+    *)
+      AC_DEFINE([NEED_PRINTF_INFINITE_DOUBLE], [1],
+        [Define if the vasnprintf implementation needs special code for
+         infinite 'double' arguments.])
+      ;;
+  esac
+])
+
+# Extra prerequisites of lib/vasnprintf.c for supporting infinite 'long double'
+# arguments.
+AC_DEFUN([gl_PREREQ_VASNPRINTF_INFINITE_LONG_DOUBLE],
+[
+  AC_REQUIRE([gl_PRINTF_INFINITE_LONG_DOUBLE])
+  dnl There is no need to set NEED_PRINTF_INFINITE_LONG_DOUBLE if
+  dnl NEED_PRINTF_LONG_DOUBLE is already set.
+  AC_REQUIRE([gl_PREREQ_VASNPRINTF_LONG_DOUBLE])
+  case "$gl_cv_func_printf_long_double" in
+    *yes)
+      case "$gl_cv_func_printf_infinite_long_double" in
+        *yes)
+          ;;
+        *)
+          AC_DEFINE([NEED_PRINTF_INFINITE_LONG_DOUBLE], [1],
+            [Define if the vasnprintf implementation needs special code for
+             infinite 'long double' arguments.])
+          ;;
+      esac
+      ;;
+  esac
+])
+
+# Extra prerequisites of lib/vasnprintf.c for supporting the 'a' directive.
+AC_DEFUN([gl_PREREQ_VASNPRINTF_DIRECTIVE_A],
+[
+  AC_REQUIRE([gl_PRINTF_DIRECTIVE_A])
+  case "$gl_cv_func_printf_directive_a" in
+    *yes)
+      ;;
+    *)
+      AC_DEFINE([NEED_PRINTF_DIRECTIVE_A], [1],
+        [Define if the vasnprintf implementation needs special code for
+         the 'a' and 'A' directives.])
+      AC_CHECK_FUNCS([nl_langinfo])
+      ;;
+  esac
+])
+
+# Extra prerequisites of lib/vasnprintf.c for supporting the 'F' directive.
+AC_DEFUN([gl_PREREQ_VASNPRINTF_DIRECTIVE_F],
+[
+  AC_REQUIRE([gl_PRINTF_DIRECTIVE_F])
+  case "$gl_cv_func_printf_directive_f" in
+    *yes)
+      ;;
+    *)
+      AC_DEFINE([NEED_PRINTF_DIRECTIVE_F], [1],
+        [Define if the vasnprintf implementation needs special code for
+         the 'F' directive.])
+      ;;
+  esac
+])
+
+# Extra prerequisites of lib/vasnprintf.c for supporting the 'ls' directive.
+AC_DEFUN([gl_PREREQ_VASNPRINTF_DIRECTIVE_LS],
+[
+  AC_REQUIRE([gl_PRINTF_DIRECTIVE_LS])
+  case "$gl_cv_func_printf_directive_ls" in
+    *yes)
+      ;;
+    *)
+      AC_DEFINE([NEED_PRINTF_DIRECTIVE_LS], [1],
+        [Define if the vasnprintf implementation needs special code for
+         the 'ls' directive.])
+      ;;
+  esac
+])
+
+# Extra prerequisites of lib/vasnprintf.c for supporting the ' flag.
+AC_DEFUN([gl_PREREQ_VASNPRINTF_FLAG_GROUPING],
+[
+  AC_REQUIRE([gl_PRINTF_FLAG_GROUPING])
+  case "$gl_cv_func_printf_flag_grouping" in
+    *yes)
+      ;;
+    *)
+      AC_DEFINE([NEED_PRINTF_FLAG_GROUPING], [1],
+        [Define if the vasnprintf implementation needs special code for the
+         ' flag.])
+      ;;
+  esac
+])
+
+# Extra prerequisites of lib/vasnprintf.c for supporting the '-' flag.
+AC_DEFUN([gl_PREREQ_VASNPRINTF_FLAG_LEFTADJUST],
+[
+  AC_REQUIRE([gl_PRINTF_FLAG_LEFTADJUST])
+  case "$gl_cv_func_printf_flag_leftadjust" in
+    *yes)
+      ;;
+    *)
+      AC_DEFINE([NEED_PRINTF_FLAG_LEFTADJUST], [1],
+        [Define if the vasnprintf implementation needs special code for the
+         '-' flag.])
+      ;;
+  esac
+])
+
+# Extra prerequisites of lib/vasnprintf.c for supporting the 0 flag.
+AC_DEFUN([gl_PREREQ_VASNPRINTF_FLAG_ZERO],
+[
+  AC_REQUIRE([gl_PRINTF_FLAG_ZERO])
+  case "$gl_cv_func_printf_flag_zero" in
+    *yes)
+      ;;
+    *)
+      AC_DEFINE([NEED_PRINTF_FLAG_ZERO], [1],
+        [Define if the vasnprintf implementation needs special code for the
+         0 flag.])
+      ;;
+  esac
+])
+
+# Extra prerequisites of lib/vasnprintf.c for supporting large precisions.
+AC_DEFUN([gl_PREREQ_VASNPRINTF_PRECISION],
+[
+  AC_REQUIRE([gl_PRINTF_PRECISION])
+  case "$gl_cv_func_printf_precision" in
+    *yes)
+      ;;
+    *)
+      AC_DEFINE([NEED_PRINTF_UNBOUNDED_PRECISION], [1],
+        [Define if the vasnprintf implementation needs special code for
+         supporting large precisions without arbitrary bounds.])
+      AC_DEFINE([NEED_PRINTF_DOUBLE], [1],
+        [Define if the vasnprintf implementation needs special code for
+         'double' arguments.])
+      AC_DEFINE([NEED_PRINTF_LONG_DOUBLE], [1],
+        [Define if the vasnprintf implementation needs special code for
+         'long double' arguments.])
+      ;;
+  esac
+])
+
+# Extra prerequisites of lib/vasnprintf.c for surviving out-of-memory
+# conditions.
+AC_DEFUN([gl_PREREQ_VASNPRINTF_ENOMEM],
+[
+  AC_REQUIRE([gl_PRINTF_ENOMEM])
+  case "$gl_cv_func_printf_enomem" in
+    *yes)
+      ;;
+    *)
+      AC_DEFINE([NEED_PRINTF_ENOMEM], [1],
+        [Define if the vasnprintf implementation needs special code for
+         surviving out-of-memory conditions.])
+      AC_DEFINE([NEED_PRINTF_DOUBLE], [1],
+        [Define if the vasnprintf implementation needs special code for
+         'double' arguments.])
+      AC_DEFINE([NEED_PRINTF_LONG_DOUBLE], [1],
+        [Define if the vasnprintf implementation needs special code for
+         'long double' arguments.])
+      ;;
+  esac
+])
+
+# Prerequisites of lib/vasnprintf.c including all extras for POSIX compliance.
+AC_DEFUN([gl_PREREQ_VASNPRINTF_WITH_EXTRAS],
+[
+  AC_REQUIRE([gl_PREREQ_VASNPRINTF])
+  gl_PREREQ_VASNPRINTF_LONG_DOUBLE
+  gl_PREREQ_VASNPRINTF_INFINITE_DOUBLE
+  gl_PREREQ_VASNPRINTF_INFINITE_LONG_DOUBLE
+  gl_PREREQ_VASNPRINTF_DIRECTIVE_A
+  gl_PREREQ_VASNPRINTF_DIRECTIVE_F
+  gl_PREREQ_VASNPRINTF_DIRECTIVE_LS
+  gl_PREREQ_VASNPRINTF_FLAG_GROUPING
+  gl_PREREQ_VASNPRINTF_FLAG_LEFTADJUST
+  gl_PREREQ_VASNPRINTF_FLAG_ZERO
+  gl_PREREQ_VASNPRINTF_PRECISION
+  gl_PREREQ_VASNPRINTF_ENOMEM
+])
+
+# Prerequisites of lib/asnprintf.c.
+AC_DEFUN([gl_PREREQ_ASNPRINTF],
+[
+])
diff --git a/m4/vasprintf.m4 b/m4/vasprintf.m4
new file mode 100644
index 0000000..299f46d
--- /dev/null
+++ b/m4/vasprintf.m4
@@ -0,0 +1,46 @@
+# vasprintf.m4 serial 6
+dnl Copyright (C) 2002-2003, 2006-2007, 2009-2020 Free Software Foundation,
+dnl Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_VASPRINTF],
+[
+  AC_CHECK_FUNCS([vasprintf])
+  if test $ac_cv_func_vasprintf = no; then
+    gl_REPLACE_VASPRINTF
+  fi
+])
+
+AC_DEFUN([gl_REPLACE_VASPRINTF],
+[
+  AC_LIBOBJ([vasprintf])
+  AC_LIBOBJ([asprintf])
+  AC_REQUIRE([gl_STDIO_H_DEFAULTS])
+  if test $ac_cv_func_vasprintf = yes; then
+    REPLACE_VASPRINTF=1
+  else
+    HAVE_VASPRINTF=0
+  fi
+  gl_PREREQ_VASPRINTF_H
+  gl_PREREQ_VASPRINTF
+  gl_PREREQ_ASPRINTF
+])
+
+# Prerequisites of the vasprintf portion of lib/stdio.h.
+AC_DEFUN([gl_PREREQ_VASPRINTF_H],
+[
+  dnl Persuade glibc <stdio.h> to declare asprintf() and vasprintf().
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
+])
+
+# Prerequisites of lib/vasprintf.c.
+AC_DEFUN([gl_PREREQ_VASPRINTF],
+[
+])
+
+# Prerequisites of lib/asprintf.c.
+AC_DEFUN([gl_PREREQ_ASPRINTF],
+[
+])
diff --git a/m4/visibility.m4 b/m4/visibility.m4
new file mode 100644
index 0000000..9f493ba
--- /dev/null
+++ b/m4/visibility.m4
@@ -0,0 +1,77 @@
+# visibility.m4 serial 6
+dnl Copyright (C) 2005, 2008, 2010-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl From Bruno Haible.
+
+dnl Tests whether the compiler supports the command-line option
+dnl -fvisibility=hidden and the function and variable attributes
+dnl __attribute__((__visibility__("hidden"))) and
+dnl __attribute__((__visibility__("default"))).
+dnl Does *not* test for __visibility__("protected") - which has tricky
+dnl semantics (see the 'vismain' test in glibc) and does not exist e.g. on
+dnl Mac OS X.
+dnl Does *not* test for __visibility__("internal") - which has processor
+dnl dependent semantics.
+dnl Does *not* test for #pragma GCC visibility push(hidden) - which is
+dnl "really only recommended for legacy code".
+dnl Set the variable CFLAG_VISIBILITY.
+dnl Defines and sets the variable HAVE_VISIBILITY.
+
+AC_DEFUN([gl_VISIBILITY],
+[
+  AC_REQUIRE([AC_PROG_CC])
+  CFLAG_VISIBILITY=
+  HAVE_VISIBILITY=0
+  if test -n "$GCC"; then
+    dnl First, check whether -Werror can be added to the command line, or
+    dnl whether it leads to an error because of some other option that the
+    dnl user has put into $CC $CFLAGS $CPPFLAGS.
+    AC_CACHE_CHECK([whether the -Werror option is usable],
+      [gl_cv_cc_vis_werror],
+      [gl_save_CFLAGS="$CFLAGS"
+       CFLAGS="$CFLAGS -Werror"
+       AC_COMPILE_IFELSE(
+         [AC_LANG_PROGRAM([[]], [[]])],
+         [gl_cv_cc_vis_werror=yes],
+         [gl_cv_cc_vis_werror=no])
+       CFLAGS="$gl_save_CFLAGS"
+      ])
+    dnl Now check whether visibility declarations are supported.
+    AC_CACHE_CHECK([for simple visibility declarations],
+      [gl_cv_cc_visibility],
+      [gl_save_CFLAGS="$CFLAGS"
+       CFLAGS="$CFLAGS -fvisibility=hidden"
+       dnl We use the option -Werror and a function dummyfunc, because on some
+       dnl platforms (Cygwin 1.7) the use of -fvisibility triggers a warning
+       dnl "visibility attribute not supported in this configuration; ignored"
+       dnl at the first function definition in every compilation unit, and we
+       dnl don't want to use the option in this case.
+       if test $gl_cv_cc_vis_werror = yes; then
+         CFLAGS="$CFLAGS -Werror"
+       fi
+       AC_COMPILE_IFELSE(
+         [AC_LANG_PROGRAM(
+            [[extern __attribute__((__visibility__("hidden"))) int hiddenvar;
+              extern __attribute__((__visibility__("default"))) int exportedvar;
+              extern __attribute__((__visibility__("hidden"))) int hiddenfunc (void);
+              extern __attribute__((__visibility__("default"))) int exportedfunc (void);
+              void dummyfunc (void) {}
+            ]],
+            [[]])],
+         [gl_cv_cc_visibility=yes],
+         [gl_cv_cc_visibility=no])
+       CFLAGS="$gl_save_CFLAGS"
+      ])
+    if test $gl_cv_cc_visibility = yes; then
+      CFLAG_VISIBILITY="-fvisibility=hidden"
+      HAVE_VISIBILITY=1
+    fi
+  fi
+  AC_SUBST([CFLAG_VISIBILITY])
+  AC_SUBST([HAVE_VISIBILITY])
+  AC_DEFINE_UNQUOTED([HAVE_VISIBILITY], [$HAVE_VISIBILITY],
+    [Define to 1 or 0, depending whether the compiler supports simple visibility declarations.])
+])
diff --git a/m4/vsnprintf.m4 b/m4/vsnprintf.m4
new file mode 100644
index 0000000..065d234
--- /dev/null
+++ b/m4/vsnprintf.m4
@@ -0,0 +1,62 @@
+# vsnprintf.m4 serial 7
+dnl Copyright (C) 2002-2004, 2007-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl Libintl 0.17 will replace vsnprintf only if it does not support %1$s,
+dnl but defers to any gnulib vsnprintf replacements.  Therefore, gnulib
+dnl must guarantee that the decision for replacing vsnprintf is a superset
+dnl of the reasons checked by libintl.
+AC_DEFUN([gl_FUNC_VSNPRINTF],
+[
+  AC_REQUIRE([gl_STDIO_H_DEFAULTS])
+  gl_cv_func_vsnprintf_usable=no
+  AC_CHECK_FUNCS([vsnprintf])
+  if test $ac_cv_func_vsnprintf = yes; then
+    gl_SNPRINTF_SIZE1
+    case "$gl_cv_func_snprintf_size1" in
+      *yes)
+        gl_SNPRINTF_RETVAL_C99
+        case "$gl_cv_func_snprintf_retval_c99" in
+          *yes)
+            gl_PRINTF_POSITIONS
+            case "$gl_cv_func_printf_positions" in
+              *yes)
+                gl_cv_func_vsnprintf_usable=yes
+                ;;
+            esac
+            ;;
+        esac
+        ;;
+    esac
+  fi
+  if test $gl_cv_func_vsnprintf_usable = no; then
+    gl_REPLACE_VSNPRINTF
+  fi
+  AC_CHECK_DECLS_ONCE([vsnprintf])
+  if test $ac_cv_have_decl_vsnprintf = no; then
+    HAVE_DECL_VSNPRINTF=0
+  fi
+])
+
+AC_DEFUN([gl_REPLACE_VSNPRINTF],
+[
+  AC_REQUIRE([gl_STDIO_H_DEFAULTS])
+  AC_LIBOBJ([vsnprintf])
+  if test $ac_cv_func_vsnprintf = yes; then
+    REPLACE_VSNPRINTF=1
+  else
+    AC_CHECK_DECLS_ONCE([vsnprintf])
+    if test $ac_cv_have_decl_vsnprintf = yes; then
+      dnl If the function is declared but does not appear to exist, it may be
+      dnl defined as an inline function. In order to avoid a conflict, we have
+      dnl to define rpl_vsnprintf, not vsnprintf.
+      REPLACE_VSNPRINTF=1
+    fi
+  fi
+  gl_PREREQ_VSNPRINTF
+])
+
+# Prerequisites of lib/vsnprintf.c.
+AC_DEFUN([gl_PREREQ_VSNPRINTF], [:])
diff --git a/m4/wait-process.m4 b/m4/wait-process.m4
new file mode 100644
index 0000000..44108a4
--- /dev/null
+++ b/m4/wait-process.m4
@@ -0,0 +1,12 @@
+# wait-process.m4 serial 6
+dnl Copyright (C) 2003, 2008-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_WAIT_PROCESS],
+[
+  dnl Prerequisites of lib/wait-process.c.
+  AC_REQUIRE([gt_TYPE_SIG_ATOMIC_T])
+  AC_CHECK_FUNCS([waitid])
+])
diff --git a/m4/waitpid.m4 b/m4/waitpid.m4
new file mode 100644
index 0000000..e1d6bed
--- /dev/null
+++ b/m4/waitpid.m4
@@ -0,0 +1,14 @@
+# waitpid.m4 serial 2
+dnl Copyright (C) 2010-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_WAITPID],
+[
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  HAVE_WAITPID=1
+  case $host_os in
+    mingw*) HAVE_WAITPID=0 ;;
+  esac
+])
diff --git a/m4/warn-on-use.m4 b/m4/warn-on-use.m4
new file mode 100644
index 0000000..1d2bcdf
--- /dev/null
+++ b/m4/warn-on-use.m4
@@ -0,0 +1,49 @@
+# warn-on-use.m4 serial 9
+dnl Copyright (C) 2010-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+# gl_WARN_ON_USE_PREPARE(INCLUDES, NAMES)
+# ---------------------------------------
+# If the module 'posixcheck' is in use:
+#
+# For each whitespace-separated element in the list of NAMES, define
+# HAVE_RAW_DECL_name if the function has a declaration among INCLUDES
+# even after being undefined as a macro.
+#
+# See warn-on-use.h for some hints on how to poison function names, as
+# well as ideas on poisoning global variables and macros.  NAMES may
+# include global variables, but remember that only functions work with
+# _GL_WARN_ON_USE.  Typically, INCLUDES only needs to list a single
+# header, but if the replacement header pulls in other headers because
+# some systems declare functions in the wrong header, then INCLUDES
+# should do likewise.
+#
+# It is generally safe to assume declarations for functions declared
+# in the intersection of C89 and C11 (such as printf) without
+# needing gl_WARN_ON_USE_PREPARE.
+AC_DEFUN([gl_WARN_ON_USE_PREPARE],
+[
+  m4_ifdef([gl_POSIXCHECK],
+    [m4_foreach_w([gl_decl], [$2],
+       [AH_TEMPLATE([HAVE_RAW_DECL_]AS_TR_CPP(m4_defn([gl_decl])),
+         [Define to 1 if ]m4_defn([gl_decl])[ is declared even after
+          undefining macros.])])dnl
+     for gl_func in m4_flatten([$2]); do
+       AS_VAR_PUSHDEF([gl_Symbol], [gl_cv_have_raw_decl_$gl_func])dnl
+       AC_CACHE_CHECK([whether $gl_func is declared without a macro],
+         [gl_Symbol],
+         [AC_COMPILE_IFELSE([AC_LANG_PROGRAM([$1],
+[[#undef $gl_func
+  (void) $gl_func;]])],
+           [AS_VAR_SET([gl_Symbol], [yes])], [AS_VAR_SET([gl_Symbol], [no])])])
+       AS_VAR_IF([gl_Symbol], [yes],
+         [AC_DEFINE_UNQUOTED(AS_TR_CPP([HAVE_RAW_DECL_$gl_func]), [1])
+          dnl shortcut - if the raw declaration exists, then set a cache
+          dnl variable to allow skipping any later AC_CHECK_DECL efforts
+          eval ac_cv_have_decl_$gl_func=yes])
+       AS_VAR_POPDEF([gl_Symbol])dnl
+     done
+    ])
+])
diff --git a/m4/warnings.m4 b/m4/warnings.m4
new file mode 100644
index 0000000..d4e4b07
--- /dev/null
+++ b/m4/warnings.m4
@@ -0,0 +1,110 @@
+# warnings.m4 serial 16
+dnl Copyright (C) 2008-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl From Simon Josefsson
+
+# gl_AS_VAR_APPEND(VAR, VALUE)
+# ----------------------------
+# Provide the functionality of AS_VAR_APPEND if Autoconf does not have it.
+m4_ifdef([AS_VAR_APPEND],
+[m4_copy([AS_VAR_APPEND], [gl_AS_VAR_APPEND])],
+[m4_define([gl_AS_VAR_APPEND],
+[AS_VAR_SET([$1], [AS_VAR_GET([$1])$2])])])
+
+
+# gl_COMPILER_OPTION_IF(OPTION, [IF-SUPPORTED], [IF-NOT-SUPPORTED],
+#                       [PROGRAM = AC_LANG_PROGRAM()])
+# -----------------------------------------------------------------
+# Check if the compiler supports OPTION when compiling PROGRAM.
+#
+# The effects of this macro depend on the current language (_AC_LANG).
+AC_DEFUN([gl_COMPILER_OPTION_IF],
+[
+AS_VAR_PUSHDEF([gl_Warn], [gl_cv_warn_[]_AC_LANG_ABBREV[]_$1])dnl
+AS_VAR_PUSHDEF([gl_Flags], [_AC_LANG_PREFIX[]FLAGS])dnl
+AS_LITERAL_IF([$1],
+  [m4_pushdef([gl_Positive], m4_bpatsubst([$1], [^-Wno-], [-W]))],
+  [gl_positive="$1"
+case $gl_positive in
+  -Wno-*) gl_positive=-W`expr "X$gl_positive" : 'X-Wno-\(.*\)'` ;;
+esac
+m4_pushdef([gl_Positive], [$gl_positive])])dnl
+AC_CACHE_CHECK([whether _AC_LANG compiler handles $1], [gl_Warn], [
+  gl_save_compiler_FLAGS="$gl_Flags"
+  gl_AS_VAR_APPEND(m4_defn([gl_Flags]),
+    [" $gl_unknown_warnings_are_errors ]m4_defn([gl_Positive])["])
+  AC_LINK_IFELSE([m4_default([$4], [AC_LANG_PROGRAM([[]])])],
+                 [AS_VAR_SET([gl_Warn], [yes])],
+                 [AS_VAR_SET([gl_Warn], [no])])
+  gl_Flags="$gl_save_compiler_FLAGS"
+])
+AS_VAR_IF(gl_Warn, [yes], [$2], [$3])
+m4_popdef([gl_Positive])dnl
+AS_VAR_POPDEF([gl_Flags])dnl
+AS_VAR_POPDEF([gl_Warn])dnl
+])
+
+# gl_UNKNOWN_WARNINGS_ARE_ERRORS
+# ------------------------------
+# Clang doesn't complain about unknown warning options unless one also
+# specifies -Wunknown-warning-option -Werror.  Detect this.
+#
+# The effects of this macro depend on the current language (_AC_LANG).
+AC_DEFUN([gl_UNKNOWN_WARNINGS_ARE_ERRORS],
+[_AC_LANG_DISPATCH([$0], _AC_LANG, $@)])
+
+# Specialization for _AC_LANG = C. This macro can be AC_REQUIREd.
+AC_DEFUN([gl_UNKNOWN_WARNINGS_ARE_ERRORS(C)],
+[
+  AC_LANG_PUSH([C])
+  gl_UNKNOWN_WARNINGS_ARE_ERRORS_IMPL
+  AC_LANG_POP([C])
+])
+
+# Specialization for _AC_LANG = C++. This macro can be AC_REQUIREd.
+AC_DEFUN([gl_UNKNOWN_WARNINGS_ARE_ERRORS(C++)],
+[
+  AC_LANG_PUSH([C++])
+  gl_UNKNOWN_WARNINGS_ARE_ERRORS_IMPL
+  AC_LANG_POP([C++])
+])
+
+# Specialization for _AC_LANG = Objective C. This macro can be AC_REQUIREd.
+AC_DEFUN([gl_UNKNOWN_WARNINGS_ARE_ERRORS(Objective C)],
+[
+  AC_LANG_PUSH([Objective C])
+  gl_UNKNOWN_WARNINGS_ARE_ERRORS_IMPL
+  AC_LANG_POP([Objective C])
+])
+
+AC_DEFUN([gl_UNKNOWN_WARNINGS_ARE_ERRORS_IMPL],
+[gl_COMPILER_OPTION_IF([-Werror -Wunknown-warning-option],
+   [gl_unknown_warnings_are_errors='-Wunknown-warning-option -Werror'],
+   [gl_unknown_warnings_are_errors=])])
+
+# gl_WARN_ADD(OPTION, [VARIABLE = WARN_CFLAGS/WARN_CXXFLAGS],
+#             [PROGRAM = AC_LANG_PROGRAM()])
+# -----------------------------------------------------------
+# Adds parameter to WARN_CFLAGS/WARN_CXXFLAGS if the compiler supports it
+# when compiling PROGRAM.  For example, gl_WARN_ADD([-Wparentheses]).
+#
+# If VARIABLE is a variable name, AC_SUBST it.
+#
+# The effects of this macro depend on the current language (_AC_LANG).
+AC_DEFUN([gl_WARN_ADD],
+[AC_REQUIRE([gl_UNKNOWN_WARNINGS_ARE_ERRORS(]_AC_LANG[)])
+gl_COMPILER_OPTION_IF([$1],
+  [gl_AS_VAR_APPEND(m4_if([$2], [], [[WARN_]_AC_LANG_PREFIX[FLAGS]], [[$2]]), [" $1"])],
+  [],
+  [$3])
+m4_ifval([$2],
+         [AS_LITERAL_IF([$2], [AC_SUBST([$2])])],
+         [AC_SUBST([WARN_]_AC_LANG_PREFIX[FLAGS])])dnl
+])
+
+# Local Variables:
+# mode: autoconf
+# End:
diff --git a/m4/wchar_h.m4 b/m4/wchar_h.m4
new file mode 100644
index 0000000..68441d2
--- /dev/null
+++ b/m4/wchar_h.m4
@@ -0,0 +1,240 @@
+dnl A placeholder for ISO C99 <wchar.h>, for platforms that have issues.
+
+dnl Copyright (C) 2007-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl Written by Eric Blake.
+
+# wchar_h.m4 serial 50
+
+AC_DEFUN([gl_WCHAR_H],
+[
+  AC_REQUIRE([gl_WCHAR_H_DEFAULTS])
+  AC_REQUIRE([gl_WCHAR_H_INLINE_OK])
+  dnl Prepare for creating substitute <wchar.h>.
+  dnl Check for <wchar.h> (missing in Linux uClibc when built without wide
+  dnl character support).
+  dnl <wchar.h> is always overridden, because of GNULIB_POSIXCHECK.
+  gl_CHECK_NEXT_HEADERS([wchar.h])
+  if test $ac_cv_header_wchar_h = yes; then
+    HAVE_WCHAR_H=1
+  else
+    HAVE_WCHAR_H=0
+  fi
+  AC_SUBST([HAVE_WCHAR_H])
+
+  AC_REQUIRE([gl_FEATURES_H])
+
+  AC_REQUIRE([gt_TYPE_WINT_T])
+  if test $gt_cv_c_wint_t = yes; then
+    HAVE_WINT_T=1
+  else
+    HAVE_WINT_T=0
+  fi
+  AC_SUBST([HAVE_WINT_T])
+
+  AC_REQUIRE([gl_TYPE_WINT_T_PREREQ])
+
+  dnl Check for declarations of anything we want to poison if the
+  dnl corresponding gnulib module is not in use.
+  gl_WARN_ON_USE_PREPARE([[
+      #include <wchar.h>
+    ]],
+    [btowc wctob mbsinit mbrtowc mbrlen mbsrtowcs mbsnrtowcs wcrtomb
+     wcsrtombs wcsnrtombs wcwidth
+     wmemchr wmemcmp wmemcpy wmemmove wmempcpy wmemset
+     wcslen wcsnlen wcscpy wcpcpy wcsncpy wcpncpy wcscat wcsncat wcscmp
+     wcsncmp wcscasecmp wcsncasecmp wcscoll wcsxfrm wcsdup wcschr wcsrchr
+     wcscspn wcsspn wcspbrk wcsstr wcstok wcswidth wcsftime
+    ])
+
+  AC_REQUIRE([AC_C_RESTRICT])
+
+  AC_CHECK_DECLS([wcsdup], [], [], [[
+      #include <wchar.h>
+    ]])
+  if test $ac_cv_have_decl_wcsdup = no; then
+    HAVE_DECL_WCSDUP=0
+  fi
+])
+
+dnl Check whether <wchar.h> is usable at all.
+AC_DEFUN([gl_WCHAR_H_INLINE_OK],
+[
+  dnl Test whether <wchar.h> suffers due to the transition from '__inline' to
+  dnl 'gnu_inline'. See <https://sourceware.org/bugzilla/show_bug.cgi?id=4022>
+  dnl and <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=42440>. In summary,
+  dnl glibc version 2.5 or older, together with gcc version 4.3 or newer and
+  dnl the option -std=c99 or -std=gnu99, leads to a broken <wchar.h>.
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  AC_CACHE_CHECK([whether <wchar.h> uses 'inline' correctly],
+    [gl_cv_header_wchar_h_correct_inline],
+    [gl_cv_header_wchar_h_correct_inline=yes
+     case "$host_os" in
+       *-gnu* | gnu*)
+         AC_LANG_CONFTEST([
+           AC_LANG_SOURCE([[
+             #define wcstod renamed_wcstod
+             #include <wchar.h>
+             extern int zero (void);
+             int main () { return zero(); }
+           ]])])
+         dnl Do not rename the object file from conftest.$ac_objext to
+         dnl conftest1.$ac_objext, as this will cause the link to fail on
+         dnl z/OS when using the XPLINK object format (due to duplicate
+         dnl CSECT names). Instead, temporarily redefine $ac_compile so
+         dnl that the object file has the latter name from the start.
+         save_ac_compile="$ac_compile"
+         ac_compile=`echo "$save_ac_compile" | sed s/conftest/conftest1/`
+         if echo '#include "conftest.c"' >conftest1.c \
+            && AC_TRY_EVAL([ac_compile]); then
+           AC_LANG_CONFTEST([
+             AC_LANG_SOURCE([[
+               #define wcstod renamed_wcstod
+               #include <wchar.h>
+               int zero (void) { return 0; }
+             ]])])
+           dnl See note above about renaming object files.
+           ac_compile=`echo "$save_ac_compile" | sed s/conftest/conftest2/`
+           if echo '#include "conftest.c"' >conftest2.c \
+              && AC_TRY_EVAL([ac_compile]); then
+             if $CC -o conftest$ac_exeext $CFLAGS $LDFLAGS conftest1.$ac_objext conftest2.$ac_objext $LIBS >&AS_MESSAGE_LOG_FD 2>&1; then
+               :
+             else
+               gl_cv_header_wchar_h_correct_inline=no
+             fi
+           fi
+         fi
+         ac_compile="$save_ac_compile"
+         rm -f conftest[12].c conftest[12].$ac_objext conftest$ac_exeext
+         ;;
+     esac
+    ])
+  if test $gl_cv_header_wchar_h_correct_inline = no; then
+    AC_MSG_ERROR([<wchar.h> cannot be used with this compiler ($CC $CFLAGS $CPPFLAGS).
+This is a known interoperability problem of glibc <= 2.5 with gcc >= 4.3 in
+C99 mode. You have four options:
+  - Add the flag -fgnu89-inline to CC and reconfigure, or
+  - Fix your include files, using parts of
+    <https://sourceware.org/git/?p=glibc.git;a=commitdiff;h=b037a293a48718af30d706c2e18c929d0e69a621>, or
+  - Use a gcc version older than 4.3, or
+  - Don't use the flags -std=c99 or -std=gnu99.
+Configuration aborted.])
+  fi
+])
+
+AC_DEFUN([gl_WCHAR_MODULE_INDICATOR],
+[
+  dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
+  AC_REQUIRE([gl_WCHAR_H_DEFAULTS])
+  gl_MODULE_INDICATOR_SET_VARIABLE([$1])
+  dnl Define it also as a C macro, for the benefit of the unit tests.
+  gl_MODULE_INDICATOR_FOR_TESTS([$1])
+])
+
+AC_DEFUN([gl_WCHAR_H_DEFAULTS],
+[
+  GNULIB_BTOWC=0;       AC_SUBST([GNULIB_BTOWC])
+  GNULIB_WCTOB=0;       AC_SUBST([GNULIB_WCTOB])
+  GNULIB_MBSINIT=0;     AC_SUBST([GNULIB_MBSINIT])
+  GNULIB_MBRTOWC=0;     AC_SUBST([GNULIB_MBRTOWC])
+  GNULIB_MBRLEN=0;      AC_SUBST([GNULIB_MBRLEN])
+  GNULIB_MBSRTOWCS=0;   AC_SUBST([GNULIB_MBSRTOWCS])
+  GNULIB_MBSNRTOWCS=0;  AC_SUBST([GNULIB_MBSNRTOWCS])
+  GNULIB_WCRTOMB=0;     AC_SUBST([GNULIB_WCRTOMB])
+  GNULIB_WCSRTOMBS=0;   AC_SUBST([GNULIB_WCSRTOMBS])
+  GNULIB_WCSNRTOMBS=0;  AC_SUBST([GNULIB_WCSNRTOMBS])
+  GNULIB_WCWIDTH=0;     AC_SUBST([GNULIB_WCWIDTH])
+  GNULIB_WMEMCHR=0;     AC_SUBST([GNULIB_WMEMCHR])
+  GNULIB_WMEMCMP=0;     AC_SUBST([GNULIB_WMEMCMP])
+  GNULIB_WMEMCPY=0;     AC_SUBST([GNULIB_WMEMCPY])
+  GNULIB_WMEMMOVE=0;    AC_SUBST([GNULIB_WMEMMOVE])
+  GNULIB_WMEMPCPY=0;    AC_SUBST([GNULIB_WMEMPCPY])
+  GNULIB_WMEMSET=0;     AC_SUBST([GNULIB_WMEMSET])
+  GNULIB_WCSLEN=0;      AC_SUBST([GNULIB_WCSLEN])
+  GNULIB_WCSNLEN=0;     AC_SUBST([GNULIB_WCSNLEN])
+  GNULIB_WCSCPY=0;      AC_SUBST([GNULIB_WCSCPY])
+  GNULIB_WCPCPY=0;      AC_SUBST([GNULIB_WCPCPY])
+  GNULIB_WCSNCPY=0;     AC_SUBST([GNULIB_WCSNCPY])
+  GNULIB_WCPNCPY=0;     AC_SUBST([GNULIB_WCPNCPY])
+  GNULIB_WCSCAT=0;      AC_SUBST([GNULIB_WCSCAT])
+  GNULIB_WCSNCAT=0;     AC_SUBST([GNULIB_WCSNCAT])
+  GNULIB_WCSCMP=0;      AC_SUBST([GNULIB_WCSCMP])
+  GNULIB_WCSNCMP=0;     AC_SUBST([GNULIB_WCSNCMP])
+  GNULIB_WCSCASECMP=0;  AC_SUBST([GNULIB_WCSCASECMP])
+  GNULIB_WCSNCASECMP=0; AC_SUBST([GNULIB_WCSNCASECMP])
+  GNULIB_WCSCOLL=0;     AC_SUBST([GNULIB_WCSCOLL])
+  GNULIB_WCSXFRM=0;     AC_SUBST([GNULIB_WCSXFRM])
+  GNULIB_WCSDUP=0;      AC_SUBST([GNULIB_WCSDUP])
+  GNULIB_WCSCHR=0;      AC_SUBST([GNULIB_WCSCHR])
+  GNULIB_WCSRCHR=0;     AC_SUBST([GNULIB_WCSRCHR])
+  GNULIB_WCSCSPN=0;     AC_SUBST([GNULIB_WCSCSPN])
+  GNULIB_WCSSPN=0;      AC_SUBST([GNULIB_WCSSPN])
+  GNULIB_WCSPBRK=0;     AC_SUBST([GNULIB_WCSPBRK])
+  GNULIB_WCSSTR=0;      AC_SUBST([GNULIB_WCSSTR])
+  GNULIB_WCSTOK=0;      AC_SUBST([GNULIB_WCSTOK])
+  GNULIB_WCSWIDTH=0;    AC_SUBST([GNULIB_WCSWIDTH])
+  GNULIB_WCSFTIME=0;    AC_SUBST([GNULIB_WCSFTIME])
+  dnl Support Microsoft deprecated alias function names by default.
+  GNULIB_MDA_WCSDUP=1;  AC_SUBST([GNULIB_MDA_WCSDUP])
+  dnl Assume proper GNU behavior unless another module says otherwise.
+  HAVE_BTOWC=1;         AC_SUBST([HAVE_BTOWC])
+  HAVE_MBSINIT=1;       AC_SUBST([HAVE_MBSINIT])
+  HAVE_MBRTOWC=1;       AC_SUBST([HAVE_MBRTOWC])
+  HAVE_MBRLEN=1;        AC_SUBST([HAVE_MBRLEN])
+  HAVE_MBSRTOWCS=1;     AC_SUBST([HAVE_MBSRTOWCS])
+  HAVE_MBSNRTOWCS=1;    AC_SUBST([HAVE_MBSNRTOWCS])
+  HAVE_WCRTOMB=1;       AC_SUBST([HAVE_WCRTOMB])
+  HAVE_WCSRTOMBS=1;     AC_SUBST([HAVE_WCSRTOMBS])
+  HAVE_WCSNRTOMBS=1;    AC_SUBST([HAVE_WCSNRTOMBS])
+  HAVE_WMEMCHR=1;       AC_SUBST([HAVE_WMEMCHR])
+  HAVE_WMEMCMP=1;       AC_SUBST([HAVE_WMEMCMP])
+  HAVE_WMEMCPY=1;       AC_SUBST([HAVE_WMEMCPY])
+  HAVE_WMEMMOVE=1;      AC_SUBST([HAVE_WMEMMOVE])
+  HAVE_WMEMPCPY=1;      AC_SUBST([HAVE_WMEMPCPY])
+  HAVE_WMEMSET=1;       AC_SUBST([HAVE_WMEMSET])
+  HAVE_WCSLEN=1;        AC_SUBST([HAVE_WCSLEN])
+  HAVE_WCSNLEN=1;       AC_SUBST([HAVE_WCSNLEN])
+  HAVE_WCSCPY=1;        AC_SUBST([HAVE_WCSCPY])
+  HAVE_WCPCPY=1;        AC_SUBST([HAVE_WCPCPY])
+  HAVE_WCSNCPY=1;       AC_SUBST([HAVE_WCSNCPY])
+  HAVE_WCPNCPY=1;       AC_SUBST([HAVE_WCPNCPY])
+  HAVE_WCSCAT=1;        AC_SUBST([HAVE_WCSCAT])
+  HAVE_WCSNCAT=1;       AC_SUBST([HAVE_WCSNCAT])
+  HAVE_WCSCMP=1;        AC_SUBST([HAVE_WCSCMP])
+  HAVE_WCSNCMP=1;       AC_SUBST([HAVE_WCSNCMP])
+  HAVE_WCSCASECMP=1;    AC_SUBST([HAVE_WCSCASECMP])
+  HAVE_WCSNCASECMP=1;   AC_SUBST([HAVE_WCSNCASECMP])
+  HAVE_WCSCOLL=1;       AC_SUBST([HAVE_WCSCOLL])
+  HAVE_WCSXFRM=1;       AC_SUBST([HAVE_WCSXFRM])
+  HAVE_WCSDUP=1;        AC_SUBST([HAVE_WCSDUP])
+  HAVE_WCSCHR=1;        AC_SUBST([HAVE_WCSCHR])
+  HAVE_WCSRCHR=1;       AC_SUBST([HAVE_WCSRCHR])
+  HAVE_WCSCSPN=1;       AC_SUBST([HAVE_WCSCSPN])
+  HAVE_WCSSPN=1;        AC_SUBST([HAVE_WCSSPN])
+  HAVE_WCSPBRK=1;       AC_SUBST([HAVE_WCSPBRK])
+  HAVE_WCSSTR=1;        AC_SUBST([HAVE_WCSSTR])
+  HAVE_WCSTOK=1;        AC_SUBST([HAVE_WCSTOK])
+  HAVE_WCSWIDTH=1;      AC_SUBST([HAVE_WCSWIDTH])
+  HAVE_WCSFTIME=1;      AC_SUBST([HAVE_WCSFTIME])
+  HAVE_DECL_WCTOB=1;    AC_SUBST([HAVE_DECL_WCTOB])
+  HAVE_DECL_WCSDUP=1;   AC_SUBST([HAVE_DECL_WCSDUP])
+  HAVE_DECL_WCWIDTH=1;  AC_SUBST([HAVE_DECL_WCWIDTH])
+  REPLACE_MBSTATE_T=0;  AC_SUBST([REPLACE_MBSTATE_T])
+  REPLACE_BTOWC=0;      AC_SUBST([REPLACE_BTOWC])
+  REPLACE_WCTOB=0;      AC_SUBST([REPLACE_WCTOB])
+  REPLACE_MBSINIT=0;    AC_SUBST([REPLACE_MBSINIT])
+  REPLACE_MBRTOWC=0;    AC_SUBST([REPLACE_MBRTOWC])
+  REPLACE_MBRLEN=0;     AC_SUBST([REPLACE_MBRLEN])
+  REPLACE_MBSRTOWCS=0;  AC_SUBST([REPLACE_MBSRTOWCS])
+  REPLACE_MBSNRTOWCS=0; AC_SUBST([REPLACE_MBSNRTOWCS])
+  REPLACE_WCRTOMB=0;    AC_SUBST([REPLACE_WCRTOMB])
+  REPLACE_WCSRTOMBS=0;  AC_SUBST([REPLACE_WCSRTOMBS])
+  REPLACE_WCSNRTOMBS=0; AC_SUBST([REPLACE_WCSNRTOMBS])
+  REPLACE_WCWIDTH=0;    AC_SUBST([REPLACE_WCWIDTH])
+  REPLACE_WCSWIDTH=0;   AC_SUBST([REPLACE_WCSWIDTH])
+  REPLACE_WCSFTIME=0;   AC_SUBST([REPLACE_WCSFTIME])
+  REPLACE_WCSTOK=0;     AC_SUBST([REPLACE_WCSTOK])
+])
diff --git a/m4/wchar_t.m4 b/m4/wchar_t.m4
new file mode 100644
index 0000000..e48d464
--- /dev/null
+++ b/m4/wchar_t.m4
@@ -0,0 +1,24 @@
+# wchar_t.m4 serial 4 (gettext-0.18.2)
+dnl Copyright (C) 2002-2003, 2008-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl From Bruno Haible.
+dnl Test whether <stddef.h> has the 'wchar_t' type.
+dnl Prerequisite: AC_PROG_CC
+
+AC_DEFUN([gt_TYPE_WCHAR_T],
+[
+  AC_CACHE_CHECK([for wchar_t], [gt_cv_c_wchar_t],
+    [AC_COMPILE_IFELSE(
+       [AC_LANG_PROGRAM(
+          [[#include <stddef.h>
+            wchar_t foo = (wchar_t)'\0';]],
+          [[]])],
+       [gt_cv_c_wchar_t=yes],
+       [gt_cv_c_wchar_t=no])])
+  if test $gt_cv_c_wchar_t = yes; then
+    AC_DEFINE([HAVE_WCHAR_T], [1], [Define if you have the 'wchar_t' type.])
+  fi
+])
diff --git a/m4/wcrtomb.m4 b/m4/wcrtomb.m4
new file mode 100644
index 0000000..71c48f1
--- /dev/null
+++ b/m4/wcrtomb.m4
@@ -0,0 +1,146 @@
+# wcrtomb.m4 serial 17
+dnl Copyright (C) 2008-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_WCRTOMB],
+[
+  AC_REQUIRE([gl_WCHAR_H_DEFAULTS])
+
+  AC_REQUIRE([AC_TYPE_MBSTATE_T])
+  gl_MBSTATE_T_BROKEN
+
+  AC_CHECK_FUNCS_ONCE([wcrtomb])
+  if test $ac_cv_func_wcrtomb = no; then
+    HAVE_WCRTOMB=0
+    AC_CHECK_DECLS([wcrtomb],,, [[
+      #include <wchar.h>
+    ]])
+    if test $ac_cv_have_decl_wcrtomb = yes; then
+      dnl On Minix 3.1.8, the system's <wchar.h> declares wcrtomb() although
+      dnl it does not have the function. Avoid a collision with gnulib's
+      dnl replacement.
+      REPLACE_WCRTOMB=1
+    fi
+  else
+    dnl We don't actually need to override wcrtomb when redefining the semantics
+    dnl of the mbstate_t type. Tested on 32-bit AIX.
+    dnl if test $REPLACE_MBSTATE_T = 1; then
+    dnl   REPLACE_WCRTOMB=1
+    dnl fi
+    if test $REPLACE_WCRTOMB = 0; then
+      dnl On Android 4.3, wcrtomb produces wrong characters in the C locale.
+      dnl On AIX 4.3, OSF/1 5.1 and Solaris <= 11.3, wcrtomb (NULL, 0, NULL)
+      dnl sometimes returns 0 instead of 1.
+      AC_REQUIRE([AC_PROG_CC])
+      AC_REQUIRE([gt_LOCALE_FR])
+      AC_REQUIRE([gt_LOCALE_FR_UTF8])
+      AC_REQUIRE([gt_LOCALE_JA])
+      AC_REQUIRE([gt_LOCALE_ZH_CN])
+      AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+      AC_CACHE_CHECK([whether wcrtomb works in the C locale],
+        [gl_cv_func_wcrtomb_works],
+        [AC_RUN_IFELSE(
+           [AC_LANG_SOURCE([[
+#include <string.h>
+#include <stdlib.h>
+#include <wchar.h>
+int main ()
+{
+  mbstate_t state;
+  char out[64];
+  int count;
+  memset (&state, 0, sizeof (state));
+  out[0] = 'x';
+  count = wcrtomb (out, L'a', &state);
+  return !(count == 1 && out[0] == 'a');
+}]])],
+           [gl_cv_func_wcrtomb_works=yes],
+           [gl_cv_func_wcrtomb_works=no],
+           [case "$host_os" in
+                               # Guess no on Android.
+              linux*-android*) gl_cv_func_wcrtomb_works="guessing no";;
+                               # Guess yes otherwise.
+              *)               gl_cv_func_wcrtomb_works="guessing yes";;
+            esac
+           ])
+        ])
+      case "$gl_cv_func_wcrtomb_works" in
+        *yes) ;;
+        *) AC_DEFINE([WCRTOMB_C_LOCALE_BUG], [1],
+             [Define if the wcrtomb function does not work in the C locale.])
+           REPLACE_WCRTOMB=1 ;;
+      esac
+    fi
+    if test $REPLACE_WCRTOMB = 0; then
+      AC_CACHE_CHECK([whether wcrtomb return value is correct],
+        [gl_cv_func_wcrtomb_retval],
+        [
+          dnl Initial guess, used when cross-compiling or when no suitable locale
+          dnl is present.
+changequote(,)dnl
+          case "$host_os" in
+            # Guess no on AIX 4, OSF/1, Solaris, native Windows.
+            aix4* | osf* | solaris* | mingw*) gl_cv_func_wcrtomb_retval="guessing no" ;;
+            # Guess yes otherwise.
+            *)                                gl_cv_func_wcrtomb_retval="guessing yes" ;;
+          esac
+changequote([,])dnl
+          if test $LOCALE_FR != none || test $LOCALE_FR_UTF8 != none || test $LOCALE_JA != none || test $LOCALE_ZH_CN != none; then
+            AC_RUN_IFELSE(
+              [AC_LANG_SOURCE([[
+#include <locale.h>
+#include <string.h>
+#include <wchar.h>
+#include <stdlib.h>
+int main ()
+{
+  int result = 0;
+  if (setlocale (LC_ALL, "$LOCALE_FR") != NULL)
+    {
+      if (wcrtomb (NULL, 0, NULL) != 1)
+        result |= 1;
+    }
+  if (setlocale (LC_ALL, "$LOCALE_FR_UTF8") != NULL)
+    {
+      if (wcrtomb (NULL, 0, NULL) != 1)
+        result |= 2;
+      {
+        wchar_t wc = (wchar_t) 0xBADFACE;
+        if (mbtowc (&wc, "\303\274", 2) == 2)
+          if (wcrtomb (NULL, wc, NULL) != 1)
+            result |= 2;
+      }
+    }
+  if (setlocale (LC_ALL, "$LOCALE_JA") != NULL)
+    {
+      if (wcrtomb (NULL, 0, NULL) != 1)
+        result |= 4;
+    }
+  if (setlocale (LC_ALL, "$LOCALE_ZH_CN") != NULL)
+    {
+      if (wcrtomb (NULL, 0, NULL) != 1)
+        result |= 8;
+    }
+  return result;
+}]])],
+              [gl_cv_func_wcrtomb_retval=yes],
+              [gl_cv_func_wcrtomb_retval=no],
+              [:])
+          fi
+        ])
+      case "$gl_cv_func_wcrtomb_retval" in
+        *yes) ;;
+        *) AC_DEFINE([WCRTOMB_RETVAL_BUG], [1],
+             [Define if the wcrtomb function has an incorrect return value.])
+           REPLACE_WCRTOMB=1 ;;
+      esac
+    fi
+  fi
+])
+
+# Prerequisites of lib/wcrtomb.c.
+AC_DEFUN([gl_PREREQ_WCRTOMB], [
+  :
+])
diff --git a/m4/wctype_h.m4 b/m4/wctype_h.m4
new file mode 100644
index 0000000..5f18978
--- /dev/null
+++ b/m4/wctype_h.m4
@@ -0,0 +1,185 @@
+# wctype_h.m4 serial 26
+
+dnl A placeholder for ISO C99 <wctype.h>, for platforms that lack it.
+
+dnl Copyright (C) 2006-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl Written by Paul Eggert.
+
+AC_DEFUN([gl_WCTYPE_H],
+[
+  AC_REQUIRE([gl_WCTYPE_H_DEFAULTS])
+  AC_REQUIRE([AC_PROG_CC])
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  AC_CHECK_FUNCS_ONCE([iswcntrl])
+  if test $ac_cv_func_iswcntrl = yes; then
+    HAVE_ISWCNTRL=1
+  else
+    HAVE_ISWCNTRL=0
+  fi
+  AC_SUBST([HAVE_ISWCNTRL])
+
+  AC_REQUIRE([gt_TYPE_WINT_T])
+  if test $gt_cv_c_wint_t = yes; then
+    HAVE_WINT_T=1
+  else
+    HAVE_WINT_T=0
+  fi
+  AC_SUBST([HAVE_WINT_T])
+
+  AC_REQUIRE([gl_TYPE_WINT_T_PREREQ])
+
+  gl_CHECK_NEXT_HEADERS([wctype.h])
+  if test $ac_cv_header_wctype_h = yes; then
+    if test $ac_cv_func_iswcntrl = yes; then
+      dnl Linux libc5 has an iswprint function that returns 0 for all arguments.
+      dnl The other functions are likely broken in the same way.
+      AC_CACHE_CHECK([whether iswcntrl works], [gl_cv_func_iswcntrl_works],
+        [
+          AC_RUN_IFELSE(
+            [AC_LANG_SOURCE([[
+               #include <wchar.h>
+               #include <wctype.h>
+               int main () { return iswprint ('x') == 0; }
+            ]])],
+            [gl_cv_func_iswcntrl_works=yes], [gl_cv_func_iswcntrl_works=no],
+            [dnl Guess no on Linux libc5, yes otherwise.
+             AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <stdlib.h>
+                          #if __GNU_LIBRARY__ == 1
+                          Linux libc5 i18n is broken.
+                          #endif]], [[]])],
+              [gl_cv_func_iswcntrl_works="guessing yes"],
+              [gl_cv_func_iswcntrl_works="guessing no"])
+            ])
+        ])
+    fi
+    HAVE_WCTYPE_H=1
+  else
+    HAVE_WCTYPE_H=0
+  fi
+  AC_SUBST([HAVE_WCTYPE_H])
+
+  if test $GNULIB_OVERRIDES_WINT_T = 1; then
+    REPLACE_ISWCNTRL=1
+  else
+    case "$gl_cv_func_iswcntrl_works" in
+      *yes) REPLACE_ISWCNTRL=0 ;;
+      *)    REPLACE_ISWCNTRL=1 ;;
+    esac
+  fi
+  AC_SUBST([REPLACE_ISWCNTRL])
+
+  if test $HAVE_ISWCNTRL = 0 || test $REPLACE_ISWCNTRL = 1; then
+    dnl Redefine all of iswcntrl, ..., iswxdigit in <wctype.h>.
+    :
+  fi
+
+  if test $REPLACE_ISWCNTRL = 1; then
+    REPLACE_TOWLOWER=1
+  else
+    AC_CHECK_FUNCS([towlower])
+    if test $ac_cv_func_towlower = yes; then
+      REPLACE_TOWLOWER=0
+    else
+      AC_CHECK_DECLS([towlower],,,
+        [[#include <wchar.h>
+          #if HAVE_WCTYPE_H
+          # include <wctype.h>
+          #endif
+        ]])
+      if test $ac_cv_have_decl_towlower = yes; then
+        dnl On Minix 3.1.8, the system's <wctype.h> declares towlower() and
+        dnl towupper() although it does not have the functions. Avoid a
+        dnl collision with gnulib's replacement.
+        REPLACE_TOWLOWER=1
+      else
+        REPLACE_TOWLOWER=0
+      fi
+    fi
+  fi
+  AC_SUBST([REPLACE_TOWLOWER])
+
+  if test $HAVE_ISWCNTRL = 0 || test $REPLACE_TOWLOWER = 1; then
+    dnl Redefine towlower, towupper in <wctype.h>.
+    :
+  fi
+
+  dnl We assume that the wctype() and iswctype() functions exist if and only
+  dnl if the type wctype_t is defined in <wchar.h> or in <wctype.h> if that
+  dnl exists.
+  dnl HP-UX 11.00 declares all these in <wchar.h> and lacks <wctype.h>.
+  AC_CACHE_CHECK([for wctype_t], [gl_cv_type_wctype_t],
+    [AC_COMPILE_IFELSE(
+       [AC_LANG_PROGRAM(
+          [[#include <wchar.h>
+            #if HAVE_WCTYPE_H
+            # include <wctype.h>
+            #endif
+            wctype_t a;
+          ]],
+          [[]])],
+       [gl_cv_type_wctype_t=yes],
+       [gl_cv_type_wctype_t=no])
+    ])
+  if test $gl_cv_type_wctype_t = no; then
+    HAVE_WCTYPE_T=0
+  fi
+
+  dnl We assume that the wctrans() and towctrans() functions exist if and only
+  dnl if the type wctrans_t is defined in <wctype.h>.
+  AC_CACHE_CHECK([for wctrans_t], [gl_cv_type_wctrans_t],
+    [AC_COMPILE_IFELSE(
+       [AC_LANG_PROGRAM(
+          [[#include <wchar.h>
+            #include <wctype.h>
+            wctrans_t a;
+          ]],
+          [[]])],
+       [gl_cv_type_wctrans_t=yes],
+       [gl_cv_type_wctrans_t=no])
+    ])
+  if test $gl_cv_type_wctrans_t = no; then
+    HAVE_WCTRANS_T=0
+  fi
+
+  dnl Check for declarations of anything we want to poison if the
+  dnl corresponding gnulib module is not in use.
+  gl_WARN_ON_USE_PREPARE([[
+#if !(defined __GLIBC__ && !defined __UCLIBC__)
+# include <wchar.h>
+#endif
+#include <wctype.h>
+    ]],
+    [wctype iswctype wctrans towctrans
+    ])
+])
+
+AC_DEFUN([gl_WCTYPE_MODULE_INDICATOR],
+[
+  dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
+  AC_REQUIRE([gl_WCTYPE_H_DEFAULTS])
+  gl_MODULE_INDICATOR_SET_VARIABLE([$1])
+  dnl Define it also as a C macro, for the benefit of the unit tests.
+  gl_MODULE_INDICATOR_FOR_TESTS([$1])
+])
+
+AC_DEFUN([gl_WCTYPE_H_DEFAULTS],
+[
+  GNULIB_ISWBLANK=0;    AC_SUBST([GNULIB_ISWBLANK])
+  GNULIB_ISWDIGIT=0;    AC_SUBST([GNULIB_ISWDIGIT])
+  GNULIB_ISWXDIGIT=0;   AC_SUBST([GNULIB_ISWXDIGIT])
+  GNULIB_WCTYPE=0;      AC_SUBST([GNULIB_WCTYPE])
+  GNULIB_ISWCTYPE=0;    AC_SUBST([GNULIB_ISWCTYPE])
+  GNULIB_WCTRANS=0;     AC_SUBST([GNULIB_WCTRANS])
+  GNULIB_TOWCTRANS=0;   AC_SUBST([GNULIB_TOWCTRANS])
+  dnl Assume proper GNU behavior unless another module says otherwise.
+  HAVE_ISWBLANK=1;      AC_SUBST([HAVE_ISWBLANK])
+  HAVE_WCTYPE_T=1;      AC_SUBST([HAVE_WCTYPE_T])
+  HAVE_WCTRANS_T=1;     AC_SUBST([HAVE_WCTRANS_T])
+  REPLACE_ISWBLANK=0;   AC_SUBST([REPLACE_ISWBLANK])
+  REPLACE_ISWDIGIT=0;   AC_SUBST([REPLACE_ISWDIGIT])
+  REPLACE_ISWXDIGIT=0;  AC_SUBST([REPLACE_ISWXDIGIT])
+])
diff --git a/m4/wcwidth.m4 b/m4/wcwidth.m4
new file mode 100644
index 0000000..4c28519
--- /dev/null
+++ b/m4/wcwidth.m4
@@ -0,0 +1,113 @@
+# wcwidth.m4 serial 33
+dnl Copyright (C) 2006-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_WCWIDTH],
+[
+  AC_REQUIRE([gl_WCHAR_H_DEFAULTS])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+
+  dnl Persuade glibc <wchar.h> to declare wcwidth().
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
+
+  AC_REQUIRE([gt_TYPE_WCHAR_T])
+  AC_REQUIRE([gt_TYPE_WINT_T])
+
+  AC_CHECK_HEADERS_ONCE([wchar.h])
+  AC_CHECK_FUNCS_ONCE([wcwidth])
+
+  AC_CHECK_DECLS([wcwidth], [], [], [[
+    #include <wchar.h>
+  ]])
+  if test $ac_cv_have_decl_wcwidth != yes; then
+    HAVE_DECL_WCWIDTH=0
+  fi
+
+  if test $ac_cv_func_wcwidth != yes; then
+    AC_CACHE_CHECK([whether wcwidth is a macro],
+      [gl_cv_func_wcwidth_macro],
+      [AC_EGREP_CPP([wchar_header_defines_wcwidth], [
+#include <wchar.h>
+#ifdef wcwidth
+ wchar_header_defines_wcwidth
+#endif],
+         [gl_cv_func_wcwidth_macro=yes],
+         [gl_cv_func_wcwidth_macro=no])
+      ])
+  fi
+
+  if test $ac_cv_func_wcwidth = yes || test $gl_cv_func_wcwidth_macro = yes; then
+    HAVE_WCWIDTH=1
+    dnl On Mac OS X 10.3, wcwidth(0x0301) (COMBINING ACUTE ACCENT) returns 1.
+    dnl On NetBSD 9.0, OpenBSD 5.0, wcwidth(0x05B0) (HEBREW POINT SHEVA) returns 1.
+    dnl On NetBSD 9.0, OSF/1 5.1, wcwidth(0x200B) (ZERO WIDTH SPACE) returns 1.
+    dnl On OpenBSD 5.8, wcwidth(0xFF1A) (FULLWIDTH COLON) returns 0.
+    dnl This leads to bugs in 'ls' (coreutils).
+    dnl On Solaris 11.4, wcwidth(0x2202) (PARTIAL DIFFERENTIAL) returns 2,
+    dnl even in Western locales.
+    AC_CACHE_CHECK([whether wcwidth works reasonably in UTF-8 locales],
+      [gl_cv_func_wcwidth_works],
+      [
+        AC_RUN_IFELSE(
+          [AC_LANG_SOURCE([[
+#include <locale.h>
+#include <wchar.h>
+#if !HAVE_DECL_WCWIDTH
+extern
+# ifdef __cplusplus
+"C"
+# endif
+int wcwidth (int);
+#endif
+int main ()
+{
+  int result = 0;
+  if (setlocale (LC_ALL, "en_US.UTF-8") != NULL)
+    {
+      if (wcwidth (0x0301) > 0)
+        result |= 1;
+      if (wcwidth (0x05B0) > 0)
+        result |= 2;
+      if (wcwidth (0x200B) > 0)
+        result |= 4;
+      if (wcwidth (0xFF1A) == 0)
+        result |= 8;
+      if (wcwidth (0x2202) > 1)
+        result |= 16;
+    }
+  return result;
+}]])],
+          [gl_cv_func_wcwidth_works=yes],
+          [gl_cv_func_wcwidth_works=no],
+          [
+changequote(,)dnl
+           case "$host_os" in
+                            # Guess yes on glibc systems.
+             *-gnu* | gnu*) gl_cv_func_wcwidth_works="guessing yes";;
+                            # Guess yes on musl systems.
+             *-musl*)       gl_cv_func_wcwidth_works="guessing yes";;
+                            # Guess yes on AIX 7 systems.
+             aix[7-9]*)     gl_cv_func_wcwidth_works="guessing yes";;
+             *)             gl_cv_func_wcwidth_works="$gl_cross_guess_normal";;
+           esac
+changequote([,])dnl
+          ])
+      ])
+    case "$gl_cv_func_wcwidth_works" in
+      *yes) ;;
+      *no) REPLACE_WCWIDTH=1 ;;
+    esac
+  else
+    HAVE_WCWIDTH=0
+  fi
+  dnl We don't substitute HAVE_WCWIDTH. We assume that if the system does not
+  dnl have the wcwidth function, then it does not declare it.
+])
+
+# Prerequisites of lib/wcwidth.c.
+AC_DEFUN([gl_PREREQ_WCWIDTH], [
+  AC_REQUIRE([AC_C_INLINE])
+  :
+])
diff --git a/m4/wget.m4 b/m4/wget.m4
new file mode 100644
index 0000000..5605bc5
--- /dev/null
+++ b/m4/wget.m4
@@ -0,0 +1,188 @@
+dnl Wget-specific Autoconf macros.
+dnl Copyright (C) 1995-2011, 2018-2020 Free Software Foundation, Inc.
+
+dnl This program is free software; you can redistribute it and/or modify
+dnl it under the terms of the GNU General Public License as published by
+dnl the Free Software Foundation; either version 3 of the License, or
+dnl (at your option) any later version.
+
+dnl This program is distributed in the hope that it will be useful,
+dnl but WITHOUT ANY WARRANTY; without even the implied warranty of
+dnl MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+dnl GNU General Public License for more details.
+
+dnl You should have received a copy of the GNU General Public License
+dnl along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+dnl Additional permission under GNU GPL version 3 section 7
+
+dnl If you modify this program, or any covered work, by linking or
+dnl combining it with the OpenSSL project's OpenSSL library (or a
+dnl modified version of that library), containing parts covered by the
+dnl terms of the OpenSSL or SSLeay licenses, the Free Software Foundation
+dnl grants you additional permission to convey the resulting work.
+dnl Corresponding Source for a non-source form of such a combination
+dnl shall include the source code for the parts of OpenSSL used as well
+dnl as that of the covered work.
+
+dnl ************************************************************
+dnl START OF IPv6 AUTOCONFIGURATION SUPPORT MACROS
+dnl ************************************************************
+
+AC_DEFUN([TYPE_STRUCT_SOCKADDR_IN6],[
+  wget_have_sockaddr_in6=
+  AC_CHECK_TYPES([struct sockaddr_in6],[
+    wget_have_sockaddr_in6=yes
+  ],[
+    wget_have_sockaddr_in6=no
+  ],[
+#include <sys/types.h>
+#ifdef HAVE_SYS_SOCKET_H
+#include <sys/socket.h>
+#endif
+#ifdef HAVE_NETINET_IN_H
+#include <netinet/in.h>
+#endif
+#ifdef HAVE_WINSOCK2_H
+#include <winsock2.h>
+#endif
+#ifdef HAVE_WS2TCPIP_H
+#include <ws2tcpip.h>
+#endif
+  ])
+
+  if test "X$wget_have_sockaddr_in6" = "Xyes"; then :
+    $1
+  else :
+    $2
+  fi
+])
+
+
+AC_DEFUN([MEMBER_SIN6_SCOPE_ID],[
+  AC_REQUIRE([TYPE_STRUCT_SOCKADDR_IN6])
+
+  wget_member_sin6_scope_id=
+  if test "X$wget_have_sockaddr_in6" = "Xyes"; then
+    AC_CHECK_MEMBER([struct sockaddr_in6.sin6_scope_id],[
+      wget_member_sin6_scope_id=yes
+    ],[
+      wget_member_sin6_scope_id=no
+    ],[
+#include <sys/types.h>
+#ifdef HAVE_SYS_SOCKET_H
+#include <sys/socket.h>
+#endif
+#ifdef HAVE_NETINET_IN_H
+#include <netinet/in.h>
+#endif
+#ifdef HAVE_WINSOCK2_H
+#include <winsock2.h>
+#endif
+#ifdef HAVE_WS2TCPIP_H
+#include <ws2tcpip.h>
+#endif
+    ])
+  fi
+
+  if test "X$wget_member_sin6_scope_id" = "Xyes"; then
+    AC_DEFINE([HAVE_SOCKADDR_IN6_SCOPE_ID], 1,
+      [Define if struct sockaddr_in6 has the sin6_scope_id member])
+    $1
+  else :
+    $2
+  fi
+])
+
+
+AC_DEFUN([PROTO_INET6],[
+  AC_CACHE_CHECK([for INET6 protocol support], [wget_cv_proto_inet6],[
+    AC_PREPROC_IFELSE([AC_LANG_SOURCE([[
+#include <sys/types.h>
+#ifdef HAVE_SYS_SOCKET_H
+#include <sys/socket.h>
+#endif
+#ifdef HAVE_NETINET_IN_H
+#include <netinet/in.h>
+#endif
+#ifdef HAVE_WINSOCK2_H
+#include <winsock2.h>
+#endif
+#ifdef HAVE_WS2TCPIP_H
+#include <ws2tcpip.h>
+#endif
+#ifndef PF_INET6
+#error Missing PF_INET6
+#endif
+#ifndef AF_INET6
+#error Missing AF_INET6
+#endif
+    ]])],[
+      wget_cv_proto_inet6=yes
+    ],[
+      wget_cv_proto_inet6=no
+    ])
+  ])
+
+  if test "X$wget_cv_proto_inet6" = "Xyes"; then :
+    $1
+  else :
+    $2
+  fi
+])
+
+
+AC_DEFUN([WGET_STRUCT_SOCKADDR_STORAGE],[
+  AC_CHECK_TYPES([struct sockaddr_storage],[], [], [
+#include <sys/types.h>
+#ifdef HAVE_SYS_SOCKET_H
+#include <sys/socket.h>
+#endif
+#ifdef HAVE_WINSOCK2_H
+#include <winsock2.h>
+#endif
+])
+])
+
+dnl ************************************************************
+dnl END OF IPv6 AUTOCONFIGURATION SUPPORT MACROS
+dnl ************************************************************
+
+dnl AM_PATH_PROG_WITH_TEST(VARIABLE, PROG-TO-CHECK-FOR,
+dnl   TEST-PERFORMED-ON-FOUND_PROGRAM [, VALUE-IF-NOT-FOUND [, PATH]])
+AC_DEFUN([AM_PATH_PROG_WITH_TEST],
+[# Extract the first word of "$2", so it can be a program name with args.
+set dummy $2; ac_word=[$]2
+AC_MSG_CHECKING([for $ac_word])
+AC_CACHE_VAL(ac_cv_path_$1,
+[case "[$]$1" in
+  /*)
+  ac_cv_path_$1="[$]$1" # Let the user override the test with a path.
+  ;;
+  *)
+  IFS="${IFS= 	}"; ac_save_ifs="$IFS"; IFS="${IFS}:"
+  for ac_dir in ifelse([$5], , $PATH, [$5]); do
+    test -z "$ac_dir" && ac_dir=.
+    if test -f $ac_dir/$ac_word; then
+      if [$3]; then
+	ac_cv_path_$1="$ac_dir/$ac_word"
+	break
+      fi
+    fi
+  done
+  IFS="$ac_save_ifs"
+dnl If no 4th arg is given, leave the cache variable unset,
+dnl so AC_PATH_PROGS will keep looking.
+ifelse([$4], , , [  test -z "[$]ac_cv_path_$1" && ac_cv_path_$1="$4"
+])dnl
+  ;;
+esac])dnl
+$1="$ac_cv_path_$1"
+if test -n "[$]$1"; then
+  AC_MSG_RESULT([$]$1)
+else
+  AC_MSG_RESULT(no)
+fi
+AC_SUBST($1)dnl
+])
+
diff --git a/m4/wget_manywarnings.m4 b/m4/wget_manywarnings.m4
new file mode 100644
index 0000000..9bc5ee5
--- /dev/null
+++ b/m4/wget_manywarnings.m4
@@ -0,0 +1,92 @@
+# wget_manywarnings.m4 serial 1
+dnl Copyright (C) 2016-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl From Tim Ruehsen
+
+# wget_WORD_SET(RESULT, SET, WORDS)
+# --------------------------------------------------
+# Add each word in WORDS to SET if not already there and store in RESULT.
+# Words separated by whitespace.
+AC_DEFUN([wget_WORD_SET], [
+  ret=$2
+  words=" $2 "
+  for word in $3; do
+    if test "${words#*" $word "}" = "$words"; then ret="$ret $word"; fi
+  done
+  $1=$ret
+])
+
+# wget_WORD_REMOVE(RESULT, SET, WORDS)
+# --------------------------------------------------
+# Remove each word in WORDS from SET and store in RESULT.
+# Words separated by whitespace.
+AC_DEFUN([wget_WORD_REMOVE], [
+  ret=
+  words=" $3 "
+  for word in $2; do
+     if test "${words#*" $word "}" = "$words"; then ret="$ret $word"; fi
+  done
+  $1=$ret
+])
+
+# wget_MANYWARNINGS(VARIABLE, LANGUAGE)
+# -----------------------------
+# Add LANGUAGE related GCC warnings to VARIABLE.
+# This only works for gcc >= 4.3.
+AC_DEFUN([wget_MANYWARNINGS], [
+  #
+  # check if manywarnings is requested
+  #
+  AC_ARG_ENABLE([manywarnings],
+    [AS_HELP_STRING([--enable-manywarnings], [Turn on extra compiler warnings (for developers)])],
+    [case $enableval in
+       yes|no) ;;
+       *) AC_MSG_ERROR([Bad value $enableval for --enable-manywarnings option]) ;;
+     esac
+       wget_manywarnings=$enableval
+    ], [
+      test -f .manywarnings && wget_manywarnings=yes || wget_manywarnings=no
+    ]
+  )
+
+  $1=""
+
+  if test "$wget_manywarnings" = yes; then
+    # AC_PROG_CC sets $GCC to 'yes' if compiler is gcc
+    # AC_REQUIRE([AC_PROG_CC])
+
+    case $CC in
+      *gcc*) CCNAME="gcc";;
+      *clang*) CCNAME="clang";;
+    esac
+
+    if test "$CCNAME" = "gcc"; then
+      test -n "$2" && wget_LANGUAGE=$2 || wget_LANGUAGE=C
+
+      # add -Wall -Wextra to reduce number of warn flags
+      wget_WORD_SET([wget_WARN_CFLAGS], [$CFLAGS], ["-Wall -Wextra -Wformat=2"])
+
+      # collect all disabled warn flags in $WARN_CFLAGS
+      wget_WARN_CFLAGS=$wget_WARN_CFLAGS" "$($CC $wget_WARN_CFLAGS -Q --help=warning,$wget_LANGUAGE|\
+        awk '{ if (([$]2 == "[[disabled]]" || [$]2 == "")\
+          && [$]1!~/=/ && [$]1~/^-W/ && [$]1!~/</ && [$]1!="-Wall") print [$]1 }')
+
+      GCC_VERSION=$($CC -dumpversion | cut -f1 -d.)
+      if test $GCC_VERSION -ge 6; then
+        wget_WARN_CFLAGS=$wget_WARN_CFLAGS" -Warray-bounds=2 -Wnormalized=nfc -Wshift-overflow=2 -Wunused-const-variable=2"
+      fi
+      if test $GCC_VERSION -ge 7; then
+        wget_WARN_CFLAGS=$wget_WARN_CFLAGS" -Wformat-overflow=2 -Wformat-truncation=1 -Wstringop-overflow=2"
+      fi
+
+    elif test "$CCNAME" = "clang"; then
+      # set all warn flags on
+      wget_WORD_SET([wget_WARN_CFLAGS], [$CFLAGS], ["-Weverything"])
+    fi
+
+    $1=$wget_WARN_CFLAGS
+  fi
+])
diff --git a/m4/wint_t.m4 b/m4/wint_t.m4
new file mode 100644
index 0000000..16618e8
--- /dev/null
+++ b/m4/wint_t.m4
@@ -0,0 +1,57 @@
+# wint_t.m4 serial 10
+dnl Copyright (C) 2003, 2007-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl From Bruno Haible.
+dnl Test whether <wchar.h> has the 'wint_t' type and whether gnulib's
+dnl <wchar.h> or <wctype.h> would, if present, override 'wint_t'.
+dnl Prerequisite: AC_PROG_CC
+
+AC_DEFUN([gt_TYPE_WINT_T],
+[
+  AC_CACHE_CHECK([for wint_t], [gt_cv_c_wint_t],
+    [AC_COMPILE_IFELSE(
+       [AC_LANG_PROGRAM(
+          [[#include <wchar.h>
+            wint_t foo = (wchar_t)'\0';]],
+          [[]])],
+       [gt_cv_c_wint_t=yes],
+       [gt_cv_c_wint_t=no])])
+  if test $gt_cv_c_wint_t = yes; then
+    AC_DEFINE([HAVE_WINT_T], [1], [Define if you have the 'wint_t' type.])
+
+    dnl Determine whether gnulib's <wchar.h> or <wctype.h> would, if present,
+    dnl override 'wint_t'.
+    AC_CACHE_CHECK([whether wint_t is large enough],
+      [gl_cv_type_wint_t_large_enough],
+      [AC_COMPILE_IFELSE(
+         [AC_LANG_PROGRAM(
+            [[#include <wchar.h>
+              int verify[sizeof (wint_t) < sizeof (int) ? -1 : 1];
+            ]])],
+         [gl_cv_type_wint_t_large_enough=yes],
+         [gl_cv_type_wint_t_large_enough=no])])
+    if test $gl_cv_type_wint_t_large_enough = no; then
+      GNULIB_OVERRIDES_WINT_T=1
+    else
+      GNULIB_OVERRIDES_WINT_T=0
+    fi
+  else
+    GNULIB_OVERRIDES_WINT_T=0
+  fi
+  AC_SUBST([GNULIB_OVERRIDES_WINT_T])
+])
+
+dnl Prerequisites of the 'wint_t' override.
+AC_DEFUN([gl_TYPE_WINT_T_PREREQ],
+[
+  AC_CHECK_HEADERS_ONCE([crtdefs.h])
+  if test $ac_cv_header_crtdefs_h = yes; then
+    HAVE_CRTDEFS_H=1
+  else
+    HAVE_CRTDEFS_H=0
+  fi
+  AC_SUBST([HAVE_CRTDEFS_H])
+])
diff --git a/m4/wmemchr.m4 b/m4/wmemchr.m4
new file mode 100644
index 0000000..79dc6ab
--- /dev/null
+++ b/m4/wmemchr.m4
@@ -0,0 +1,25 @@
+# wmemchr.m4 serial 5
+dnl Copyright (C) 2011-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_WMEMCHR],
+[
+  AC_REQUIRE([gl_WCHAR_H_DEFAULTS])
+  dnl We cannot use AC_CHECK_FUNCS here, because the MSVC 9 header files
+  dnl provide this function as an inline function definition.
+  AC_CACHE_CHECK([for wmemchr], [gl_cv_func_wmemchr],
+    [AC_LINK_IFELSE(
+       [AC_LANG_PROGRAM(
+          [[#include <wchar.h>
+          ]],
+          [[return ! wmemchr ((const wchar_t *) 0, (wchar_t) ' ', 0);]])
+       ],
+       [gl_cv_func_wmemchr=yes],
+       [gl_cv_func_wmemchr=no])
+    ])
+  if test $gl_cv_func_wmemchr = no; then
+    HAVE_WMEMCHR=0
+  fi
+])
diff --git a/m4/wmempcpy.m4 b/m4/wmempcpy.m4
new file mode 100644
index 0000000..1795fc8
--- /dev/null
+++ b/m4/wmempcpy.m4
@@ -0,0 +1,21 @@
+# wmempcpy.m4 serial 1
+dnl Copyright (C) 2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_WMEMPCPY],
+[
+  AC_REQUIRE([gl_WCHAR_H_DEFAULTS])
+
+  dnl Persuade glibc <wchar.h> to declare wmempcpy().
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
+
+  dnl The wmempcpy() declaration in lib/wchar.in.h uses 'restrict'.
+  AC_REQUIRE([AC_C_RESTRICT])
+
+  AC_CHECK_FUNCS_ONCE([wmempcpy])
+  if test $ac_cv_func_wmempcpy = no; then
+    HAVE_WMEMPCPY=0
+  fi
+])
diff --git a/m4/write.m4 b/m4/write.m4
new file mode 100644
index 0000000..2727baf
--- /dev/null
+++ b/m4/write.m4
@@ -0,0 +1,34 @@
+# write.m4 serial 6
+dnl Copyright (C) 2008-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_WRITE],
+[
+  AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
+  m4_ifdef([gl_MSVC_INVAL], [
+    AC_REQUIRE([gl_MSVC_INVAL])
+    if test $HAVE_MSVC_INVALID_PARAMETER_HANDLER = 1; then
+      REPLACE_WRITE=1
+    fi
+  ])
+  dnl This ifdef is just an optimization, to avoid performing a configure
+  dnl check whose result is not used. It does not make the test of
+  dnl GNULIB_UNISTD_H_SIGPIPE or GNULIB_SIGPIPE redundant.
+  m4_ifdef([gl_SIGNAL_SIGPIPE], [
+    gl_SIGNAL_SIGPIPE
+    if test $gl_cv_header_signal_h_SIGPIPE != yes; then
+      REPLACE_WRITE=1
+    fi
+  ])
+  m4_ifdef([gl_NONBLOCKING_IO], [
+    gl_NONBLOCKING_IO
+    if test $gl_cv_have_nonblocking != yes; then
+      REPLACE_WRITE=1
+    fi
+  ])
+])
+
+# Prerequisites of lib/write.c.
+AC_DEFUN([gl_PREREQ_WRITE], [:])
diff --git a/m4/xalloc.m4 b/m4/xalloc.m4
new file mode 100644
index 0000000..a556870
--- /dev/null
+++ b/m4/xalloc.m4
@@ -0,0 +1,7 @@
+# xalloc.m4 serial 18
+dnl Copyright (C) 2002-2006, 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_XALLOC], [:])
diff --git a/m4/xsize.m4 b/m4/xsize.m4
new file mode 100644
index 0000000..978f99a
--- /dev/null
+++ b/m4/xsize.m4
@@ -0,0 +1,12 @@
+# xsize.m4 serial 5
+dnl Copyright (C) 2003-2004, 2008-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_XSIZE],
+[
+  dnl Prerequisites of lib/xsize.h.
+  AC_REQUIRE([gl_SIZE_MAX])
+  AC_CHECK_HEADERS([stdint.h])
+])
diff --git a/m4/xstrndup.m4 b/m4/xstrndup.m4
new file mode 100644
index 0000000..3846f91
--- /dev/null
+++ b/m4/xstrndup.m4
@@ -0,0 +1,15 @@
+# xstrndup.m4 serial 2
+dnl Copyright (C) 2003, 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_XSTRNDUP],
+[
+  gl_PREREQ_XSTRNDUP
+])
+
+# Prerequisites of lib/xstrndup.c.
+AC_DEFUN([gl_PREREQ_XSTRNDUP], [
+  :
+])
diff --git a/m4/zzgnulib.m4 b/m4/zzgnulib.m4
new file mode 100644
index 0000000..98fa68f
--- /dev/null
+++ b/m4/zzgnulib.m4
@@ -0,0 +1,23 @@
+# zzgnulib.m4 serial 1
+dnl Copyright (C) 2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl This file must be named something that sorts after all other
+dnl package- or gnulib-provided .m4 files - at least for those packages
+dnl that redefine AC_PROG_CC.
+
+dnl Redefine AC_PROG_CC so that it ends with invocations of gl_COMPILER_CLANG
+dnl and gl_COMPILER_PREPARE_CHECK_DECL.
+m4_define([AC_PROG_CC],
+  m4_defn([AC_PROG_CC])[
+gl_COMPILER_CLANG
+gl_COMPILER_PREPARE_CHECK_DECL
+])
+
+# gl_ZZGNULIB
+# -----------
+# Witness macro that this file has been included.  Needed to force
+# Automake to include this file after all other gnulib .m4 files.
+AC_DEFUN([gl_ZZGNULIB])
author	Daniel Baumann <daniel.baumann@progress-linux.org>	2024-04-27 17:47:50 +0000
committer	Daniel Baumann <daniel.baumann@progress-linux.org>	2024-04-27 17:47:50 +0000
commit	bbe35a6e1b54ef5cd7c1c471886c30ba85c0804e (patch)
tree	985a31e8c860c690d9f20e6621ce5fcc05ccd244 /m4
parent	Initial commit. (diff)
download	wget-bbe35a6e1b54ef5cd7c1c471886c30ba85c0804e.tar.xz wget-bbe35a6e1b54ef5cd7c1c471886c30ba85c0804e.zip