Adding upstream version 23.7.upstream/23.7upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

10 files changed, 3275 insertions, 0 deletions

diff --git a/m4/gettext.m4 b/m4/gettext.m4
new file mode 100644
index 0000000..4f25a27
--- /dev/null
+++ b/m4/gettext.m4
@@ -0,0 +1,386 @@
+# gettext.m4 serial 71 (gettext-0.20.2)
+dnl Copyright (C) 1995-2014, 2016, 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
+dnl This file can be used in projects which are not available under
+dnl the GNU General Public License or the GNU Lesser 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 Lesser General Public License, and the rest of the GNU
+dnl gettext 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 must be one of 'external', 'use-libtool'.
+dnl    INTLSYMBOL should be 'external' for packages other than GNU gettext, and
+dnl    'use-libtool' for the packages 'gettext-runtime' and 'gettext-tools'.
+dnl    If INTLSYMBOL is 'use-libtool', then a libtool library
+dnl    $(top_builddir)/intl/libintl.la will be created (shared and/or static,
+dnl    depending on --{enable,disable}-{shared,static} and on the presence of
+dnl    AM-DISABLE-SHARED).
+dnl If NEEDSYMBOL is specified and is 'need-ngettext', then GNU gettext
+dnl    implementations (in libc or libintl) without the ngettext() function
+dnl    will be ignored.  If NEEDSYMBOL is specified and is
+dnl    'need-formatstring-macros', then GNU gettext implementations that don't
+dnl    support the ISO C 99 <inttypes.h> formatstring macros will be ignored.
+dnl INTLDIR is used to find the intl libraries.  If empty,
+dnl    the value '$(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], [use-libtool], ,
+    [errprint([ERROR: invalid first argument to AM_GNU_GETTEXT
+])])])])
+  ifelse(ifelse([$1], [], [old])[]ifelse([$1], [no-libtool], [old]), [old],
+    [errprint([ERROR: Use of AM_GNU_GETTEXT without [external] argument is no longer supported.
+])])
+  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], [no], [yes]))
+  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 not 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>
+#ifndef __GNU_GETTEXT_SUPPORTED_REVISION
+extern int _nl_msg_cat_cntr;
+extern int *_nl_domain_bindings;
+#define __GNU_GETTEXT_SYMBOL_EXPRESSION (_nl_msg_cat_cntr + *_nl_domain_bindings)
+#else
+#define __GNU_GETTEXT_SYMBOL_EXPRESSION 0
+#endif
+$gt_revision_test_code
+               ]],
+               [[
+bindtextdomain ("", "");
+return * gettext ("")$gt_expression_test_code + __GNU_GETTEXT_SYMBOL_EXPRESSION
+               ]])],
+            [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 $LIBINTL"
+            dnl Now see whether libintl exists and does not depend on libiconv.
+            AC_LINK_IFELSE(
+              [AC_LANG_PROGRAM(
+                 [[
+#include <libintl.h>
+#ifndef __GNU_GETTEXT_SUPPORTED_REVISION
+extern int _nl_msg_cat_cntr;
+extern
+#ifdef __cplusplus
+"C"
+#endif
+const char *_nl_expand_alias (const char *);
+#define __GNU_GETTEXT_SYMBOL_EXPRESSION (_nl_msg_cat_cntr + *_nl_expand_alias (""))
+#else
+#define __GNU_GETTEXT_SYMBOL_EXPRESSION 0
+#endif
+$gt_revision_test_code
+                 ]],
+                 [[
+bindtextdomain ("", "");
+return * gettext ("")$gt_expression_test_code + __GNU_GETTEXT_SYMBOL_EXPRESSION
+                 ]])],
+              [eval "$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 $LIBICONV"
+              AC_LINK_IFELSE(
+                [AC_LANG_PROGRAM(
+                   [[
+#include <libintl.h>
+#ifndef __GNU_GETTEXT_SUPPORTED_REVISION
+extern int _nl_msg_cat_cntr;
+extern
+#ifdef __cplusplus
+"C"
+#endif
+const char *_nl_expand_alias (const char *);
+#define __GNU_GETTEXT_SYMBOL_EXPRESSION (_nl_msg_cat_cntr + *_nl_expand_alias (""))
+#else
+#define __GNU_GETTEXT_SYMBOL_EXPRESSION 0
+#endif
+$gt_revision_test_code
+                   ]],
+                   [[
+bindtextdomain ("", "");
+return * gettext ("")$gt_expression_test_code + __GNU_GETTEXT_SYMBOL_EXPRESSION
+                   ]])],
+                [LIBINTL="$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.la $LIBICONV $LIBTHREAD"
+        LTLIBINTL="ifelse([$3],[],\${top_builddir}/intl,[$3])/libintl.la $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], [$INCINTL])
+      fi
+
+      dnl For backward compatibility. Some packages may be using this.
+      AC_DEFINE([HAVE_GETTEXT], [1],
+       [Define if the GNU gettext() function is already present or preinstalled.])
+      AC_DEFINE([HAVE_DCGETTEXT], [1],
+       [Define if the GNU dcgettext() function is already present or preinstalled.])
+    fi
+
+    dnl We need to process the po/ directory.
+    POSUB=po
+  fi
+
+  ifelse(gt_included_intl, yes, [
+    dnl In GNU gettext we have to set BUILD_INCLUDED_LIBINTL to 'yes'
+    dnl because some of the testsuite requires it.
+    BUILD_INCLUDED_LIBINTL=yes
+
+    dnl Make all variables we use known to autoconf.
+    AC_SUBST([BUILD_INCLUDED_LIBINTL])
+    AC_SUBST([USE_INCLUDED_LIBINTL])
+    AC_SUBST([CATOBJEXT])
+  ])
+
+  dnl For backward compatibility. Some Makefiles may be using this.
+  INTLLIBS="$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 $1"])
+])
+
+
+dnl Usage: AM_GNU_GETTEXT_VERSION([gettext-version])
+AC_DEFUN([AM_GNU_GETTEXT_VERSION], [])
+
+
+dnl Usage: AM_GNU_GETTEXT_REQUIRE_VERSION([gettext-version])
+AC_DEFUN([AM_GNU_GETTEXT_REQUIRE_VERSION], [])
diff --git a/m4/host-cpu-c-abi.m4 b/m4/host-cpu-c-abi.m4
new file mode 100644
index 0000000..6db2aa2
--- /dev/null
+++ b/m4/host-cpu-c-abi.m4
@@ -0,0 +1,675 @@
+# host-cpu-c-abi.m4 serial 13
+dnl Copyright (C) 2002-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl From Bruno Haible and Sam Steingold.
+
+dnl Sets the HOST_CPU variable to the canonical name of the CPU.
+dnl Sets the HOST_CPU_C_ABI variable to the canonical name of the CPU with its
+dnl C language ABI (application binary interface).
+dnl Also defines __${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/iconv.m4 b/m4/iconv.m4
new file mode 100644
index 0000000..e593b72
--- /dev/null
+++ b/m4/iconv.m4
@@ -0,0 +1,288 @@
+# iconv.m4 serial 21
+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_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 for Autoconf >= 2.64, in order to
+dnl 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.
+m4_define([gl_iconv_AC_DEFUN],
+  m4_version_prereq([2.64],
+    [[AC_DEFUN_ONCE(
+        [$1], [$2])]],
+    [m4_ifdef([gl_00GNULIB],
+       [[AC_DEFUN_ONCE(
+           [$1], [$2])]],
+       [[AC_DEFUN(
+           [$1], [$2])]])]))
+gl_iconv_AC_DEFUN([AM_ICONV],
+[
+  AM_ICONV_LINK
+  if test "$am_cv_func_iconv" = yes; then
+    AC_MSG_CHECKING([for iconv declaration])
+    AC_CACHE_VAL([am_cv_proto_iconv], [
+      AC_COMPILE_IFELSE(
+        [AC_LANG_PROGRAM(
+           [[
+#include <stdlib.h>
+#include <iconv.h>
+extern
+#ifdef __cplusplus
+"C"
+#endif
+#if defined(__STDC__) || defined(_MSC_VER) || defined(__cplusplus)
+size_t iconv (iconv_t cd, char * *inbuf, size_t *inbytesleft, char * *outbuf, size_t *outbytesleft);
+#else
+size_t iconv();
+#endif
+           ]],
+           [[]])],
+        [am_cv_proto_iconv_arg1=""],
+        [am_cv_proto_iconv_arg1="const"])
+      am_cv_proto_iconv="extern size_t iconv (iconv_t cd, $am_cv_proto_iconv_arg1 char * *inbuf, size_t *inbytesleft, char * *outbuf, size_t *outbytesleft);"])
+    am_cv_proto_iconv=`echo "[$]am_cv_proto_iconv" | tr -s ' ' | sed -e 's/( /(/'`
+    AC_MSG_RESULT([
+         $am_cv_proto_iconv])
+  else
+    dnl When compiling GNU libiconv on a system that does not have iconv yet,
+    dnl pick the POSIX compliant declaration without 'const'.
+    am_cv_proto_iconv_arg1=""
+  fi
+  AC_DEFINE_UNQUOTED([ICONV_CONST], [$am_cv_proto_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 -n "$am_cv_proto_iconv_arg1"; then
+       ICONV_CONST="const"
+     fi
+    ])
+])
diff --git a/m4/intlmacosx.m4 b/m4/intlmacosx.m4
new file mode 100644
index 0000000..ebd9937
--- /dev/null
+++ b/m4/intlmacosx.m4
@@ -0,0 +1,65 @@
+# intlmacosx.m4 serial 8 (gettext-0.20.2)
+dnl Copyright (C) 2004-2014, 2016, 2019-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+dnl
+dnl This file can be used in projects which are not available under
+dnl the GNU General Public License or the GNU Lesser General Public
+dnl License but which still want to provide support for the GNU gettext
+dnl functionality.
+dnl Please note that the actual code of the GNU gettext library is covered
+dnl by the GNU Lesser General Public License, and the rest of the GNU
+dnl gettext package is covered by the GNU General Public License.
+dnl They are *not* in the public domain.
+
+dnl Checks for special options needed on Mac OS X.
+dnl Defines INTL_MACOSX_LIBS.
+AC_DEFUN([gt_INTL_MACOSX],
+[
+  dnl Check for API introduced in Mac OS X 10.4.
+  AC_CACHE_CHECK([for CFPreferencesCopyAppValue],
+    [gt_cv_func_CFPreferencesCopyAppValue],
+    [gt_save_LIBS="$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 $gt_cv_func_CFPreferencesCopyAppValue = yes; then
+    AC_DEFINE([HAVE_CFPREFERENCESCOPYAPPVALUE], [1],
+      [Define to 1 if you have the Mac OS X function CFPreferencesCopyAppValue in the CoreFoundation framework.])
+  fi
+  dnl Don't check for the API introduced in Mac OS X 10.5, CFLocaleCopyCurrent,
+  dnl because in macOS 10.13.4 it has the following behaviour:
+  dnl When two or more languages are specified in the
+  dnl "System Preferences > Language & Region > Preferred Languages" panel,
+  dnl it returns en_CC where CC is the territory (even when English is not among
+  dnl the preferred languages!).  What we want instead is what
+  dnl CFLocaleCopyCurrent returned in earlier macOS releases and what
+  dnl CFPreferencesCopyAppValue still returns, namely ll_CC where ll is the
+  dnl first among the preferred languages and CC is the territory.
+  AC_CACHE_CHECK([for CFLocaleCopyPreferredLanguages], [gt_cv_func_CFLocaleCopyPreferredLanguages],
+    [gt_save_LIBS="$LIBS"
+     LIBS="$LIBS -Wl,-framework -Wl,CoreFoundation"
+     AC_LINK_IFELSE(
+       [AC_LANG_PROGRAM(
+          [[#include <CoreFoundation/CFLocale.h>]],
+          [[CFLocaleCopyPreferredLanguages();]])],
+       [gt_cv_func_CFLocaleCopyPreferredLanguages=yes],
+       [gt_cv_func_CFLocaleCopyPreferredLanguages=no])
+     LIBS="$gt_save_LIBS"])
+  if test $gt_cv_func_CFLocaleCopyPreferredLanguages = yes; then
+    AC_DEFINE([HAVE_CFLOCALECOPYPREFERREDLANGUAGES], [1],
+      [Define to 1 if you have the Mac OS X function CFLocaleCopyPreferredLanguages in the CoreFoundation framework.])
+  fi
+  INTL_MACOSX_LIBS=
+  if test $gt_cv_func_CFPreferencesCopyAppValue = yes \
+     || test $gt_cv_func_CFLocaleCopyPreferredLanguages = yes; then
+    INTL_MACOSX_LIBS="-Wl,-framework -Wl,CoreFoundation"
+  fi
+  AC_SUBST([INTL_MACOSX_LIBS])
+])
diff --git a/m4/lib-ld.m4 b/m4/lib-ld.m4
new file mode 100644
index 0000000..98c348f
--- /dev/null
+++ b/m4/lib-ld.m4
@@ -0,0 +1,168 @@
+# lib-ld.m4 serial 9
+dnl Copyright (C) 1996-2003, 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl Subroutines of libtool.m4,
+dnl with replacements s/_*LT_PATH/AC_LIB_PROG/ and s/lt_/acl_/ to avoid
+dnl collision with libtool.m4.
+
+dnl From libtool-2.4. Sets the variable with_gnu_ld to yes or no.
+AC_DEFUN([AC_LIB_PROG_LD_GNU],
+[AC_CACHE_CHECK([if the linker ($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..eecf70e
--- /dev/null
+++ b/m4/lib-link.m4
@@ -0,0 +1,800 @@
+# lib-link.m4 serial 31
+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 $dir"
+                      fi
+                    fi
+                    ;;
+                  -l*)
+                    dnl Handle this in the next round.
+                    names_next_round="$names_next_round "`echo "X$dep" | sed -e 's/^X-l//'`
+                    ;;
+                  *.la)
+                    dnl Handle this in the next round. Throw away the .la's
+                    dnl directory; it is already contained in a preceding -L
+                    dnl option.
+                    names_next_round="$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..c8a0b46
--- /dev/null
+++ b/m4/lib-prefix.m4
@@ -0,0 +1,320 @@
+# lib-prefix.m4 serial 17
+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; 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
+changequote(,)dnl
+    case $HOST_CPU_C_ABI_32BIT in
+      yes)
+        # 32-bit ABI.
+        acl_is_expected_elfclass ()
+        {
+          test "`func_elfclass | sed -e 's/[ 	]//g'`" = 1
+        }
+        ;;
+      no)
+        # 64-bit ABI.
+        acl_is_expected_elfclass ()
+        {
+          test "`func_elfclass | sed -e 's/[ 	]//g'`" = 2
+        }
+        ;;
+      *)
+        # Unknown.
+        acl_is_expected_elfclass ()
+        {
+          :
+        }
+        ;;
+    esac
+changequote([,])dnl
+  else
+    acl_is_expected_elfclass ()
+    {
+      :
+    }
+  fi
+
+  dnl Allow the user to override the result by setting acl_cv_libdirstems.
+  AC_CACHE_CHECK([for the common suffixes of directories in the library search path],
+    [acl_cv_libdirstems],
+    [dnl Try 'lib' first, because that's the default for libdir in GNU, see
+     dnl <https://www.gnu.org/prep/standards/html_node/Directory-Variables.html>.
+     acl_libdirstem=lib
+     acl_libdirstem2=
+     acl_libdirstem3=
+     case "$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 "$acl_cv_libdirstems" | sed -e 's/^[^,]*,[^,]*,//' -e 's/,.*//'`
+changequote([,])dnl
+])
diff --git a/m4/nls.m4 b/m4/nls.m4
new file mode 100644
index 0000000..5a506fc
--- /dev/null
+++ b/m4/nls.m4
@@ -0,0 +1,32 @@
+# nls.m4 serial 6 (gettext-0.20.2)
+dnl Copyright (C) 1995-2003, 2005-2006, 2008-2014, 2016, 2019-2020 Free
+dnl Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+dnl
+dnl This file can be used in projects which are not available under
+dnl the GNU General Public License or the GNU Lesser General Public
+dnl License but which still want to provide support for the GNU gettext
+dnl functionality.
+dnl Please note that the actual code of the GNU gettext library is covered
+dnl by the GNU Lesser General Public License, and the rest of the GNU
+dnl gettext package is covered by the GNU General Public License.
+dnl They are *not* in the public domain.
+
+dnl Authors:
+dnl   Ulrich Drepper <drepper@cygnus.com>, 1995-2000.
+dnl   Bruno Haible <haible@clisp.cons.org>, 2000-2003.
+
+AC_PREREQ([2.50])
+
+AC_DEFUN([AM_NLS],
+[
+  AC_MSG_CHECKING([whether NLS is requested])
+  dnl Default is enabled NLS
+  AC_ARG_ENABLE([nls],
+    [  --disable-nls           do not use Native Language Support],
+    USE_NLS=$enableval, USE_NLS=yes)
+  AC_MSG_RESULT([$USE_NLS])
+  AC_SUBST([USE_NLS])
+])
diff --git a/m4/po.m4 b/m4/po.m4
new file mode 100644
index 0000000..3778fd7
--- /dev/null
+++ b/m4/po.m4
@@ -0,0 +1,450 @@
+# po.m4 serial 31 (gettext-0.20.2)
+dnl Copyright (C) 1995-2014, 2016, 2018-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+dnl
+dnl This file can be used in projects which are not available under
+dnl the GNU General Public License or the GNU Lesser General Public
+dnl License but which still want to provide support for the GNU gettext
+dnl functionality.
+dnl Please note that the actual code of the GNU gettext library is covered
+dnl by the GNU Lesser General Public License, and the rest of the GNU
+dnl gettext package is covered by the GNU General Public License.
+dnl They are *not* in the public domain.
+
+dnl Authors:
+dnl   Ulrich Drepper <drepper@cygnus.com>, 1995-2000.
+dnl   Bruno Haible <haible@clisp.cons.org>, 2000-2003.
+
+AC_PREREQ([2.60])
+
+dnl Checks for all prerequisites of the po subdirectory.
+AC_DEFUN([AM_PO_SUBDIRS],
+[
+  AC_REQUIRE([AC_PROG_MAKE_SET])dnl
+  AC_REQUIRE([AC_PROG_INSTALL])dnl
+  AC_REQUIRE([AC_PROG_MKDIR_P])dnl
+  AC_REQUIRE([AC_PROG_SED])dnl
+  AC_REQUIRE([AM_NLS])dnl
+
+  dnl Release version of the gettext macros. This is used to ensure that
+  dnl the gettext macros and po/Makefile.in.in are in sync.
+  AC_SUBST([GETTEXT_MACRO_VERSION], [0.20])
+
+  dnl Perform the following tests also if --disable-nls has been given,
+  dnl because they are needed for "make dist" to work.
+
+  dnl Search for GNU msgfmt in the PATH.
+  dnl The first test excludes Solaris msgfmt and early GNU msgfmt versions.
+  dnl The second test excludes FreeBSD msgfmt.
+  AM_PATH_PROG_WITH_TEST(MSGFMT, msgfmt,
+    [$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], [$MSGFMT])
+
+  dnl Test whether it is GNU msgfmt >= 0.15.
+changequote(,)dnl
+  case `$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 Test whether it is GNU msgmerge >= 0.20.
+  if LC_ALL=C $MSGMERGE --help | grep ' --for-msgfmt ' >/dev/null; then
+    MSGMERGE_FOR_MSGFMT_OPTION='--for-msgfmt'
+  else
+    dnl Test whether it is GNU msgmerge >= 0.12.
+    if LC_ALL=C $MSGMERGE --help | grep ' --no-fuzzy-matching ' >/dev/null; then
+      MSGMERGE_FOR_MSGFMT_OPTION='--no-fuzzy-matching --no-location --quiet'
+    else
+      dnl With these old versions, $(MSGMERGE) $(MSGMERGE_FOR_MSGFMT_OPTION) is
+      dnl slow. But this is not a big problem, as such old gettext versions are
+      dnl hardly in use any more.
+      MSGMERGE_FOR_MSGFMT_OPTION='--no-location --quiet'
+    fi
+  fi
+  AC_SUBST([MSGMERGE_FOR_MSGFMT_OPTION])
+
+  dnl Support for AM_XGETTEXT_OPTION.
+  test -n "${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"`
+            POMAKEFILEDEPS="$POMAKEFILEDEPS LINGUAS"
+          else
+            # The set of available languages was given in configure.in.
+            ALL_LINGUAS=$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.
+    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
+  # 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), $(srcdir)/$(DOMAIN)_$(lang).properties)
+  # Compute CLASSFILES
+  # as      $(foreach lang, $(ALL_LINGUAS), $(srcdir)/$(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="$PROPERTIESFILES \$(srcdir)/\$(DOMAIN)_$lang.properties"
+    CLASSFILES="$CLASSFILES \$(srcdir)/\$(DOMAIN)_$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 $1"
+])
diff --git a/m4/progtest.m4 b/m4/progtest.m4
new file mode 100644
index 0000000..f28010a
--- /dev/null
+++ b/m4/progtest.m4
@@ -0,0 +1,91 @@
+# progtest.m4 serial 8 (gettext-0.20.2)
+dnl Copyright (C) 1996-2003, 2005, 2008-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+dnl
+dnl This file can be used in projects which are not available under
+dnl the GNU General Public License or the GNU Lesser General Public
+dnl License but which still want to provide support for the GNU gettext
+dnl functionality.
+dnl Please note that the actual code of the GNU gettext library is covered
+dnl by the GNU Lesser General Public License, and the rest of the GNU
+dnl gettext package is covered by the GNU General Public License.
+dnl They are *not* in the public domain.
+
+dnl Authors:
+dnl   Ulrich Drepper <drepper@cygnus.com>, 1996.
+
+AC_PREREQ([2.50])
+
+# Search path for a program which passes the given test.
+
+dnl AM_PATH_PROG_WITH_TEST(VARIABLE, PROG-TO-CHECK-FOR,
+dnl   TEST-PERFORMED-ON-FOUND_PROGRAM [, VALUE-IF-NOT-FOUND [, PATH]])
+AC_DEFUN([AM_PATH_PROG_WITH_TEST],
+[
+# Prepare PATH_SEPARATOR.
+# The user is always right.
+if test "${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
+
+# Find out how to test for executable files. Don't use a zero-byte file,
+# as systems may use methods other than mode bits to determine executability.
+cat >conf$$.file <<_ASEOF
+#! /bin/sh
+exit 0
+_ASEOF
+chmod +x conf$$.file
+if test -x conf$$.file >/dev/null 2>&1; then
+  ac_executable_p="test -x"
+else
+  ac_executable_p="test -f"
+fi
+rm -f conf$$.file
+
+# 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_$1="[$]$1" # Let the user override the test with a path.
+    ;;
+  *)
+    ac_save_IFS="$IFS"; IFS=$PATH_SEPARATOR
+    for ac_dir in ifelse([$5], , $PATH, [$5]); do
+      IFS="$ac_save_IFS"
+      test -z "$ac_dir" && ac_dir=.
+      for ac_exec_ext in '' $ac_executable_extensions; do
+        if $ac_executable_p "$ac_dir/$ac_word$ac_exec_ext"; then
+          echo "$as_me: trying $ac_dir/$ac_word..." >&AS_MESSAGE_LOG_FD
+          if [$3]; then
+            ac_cv_path_$1="$ac_dir/$ac_word$ac_exec_ext"
+            break 2
+          fi
+        fi
+      done
+    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 ifelse([$4], , [-n "[$]$1"], ["[$]$1" != "$4"]); then
+  AC_MSG_RESULT([$][$1])
+else
+  AC_MSG_RESULT([no])
+fi
+AC_SUBST([$1])dnl
+])