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Diffstat (limited to 'm4/absolute-header.m4')
| -rw-r--r-- | m4/absolute-header.m4 | 100 |
1 files changed, 100 insertions, 0 deletions
diff --git a/m4/absolute-header.m4 b/m4/absolute-header.m4 new file mode 100644 index 0000000..67d6507 --- /dev/null +++ b/m4/absolute-header.m4 @@ -0,0 +1,100 @@ +# absolute-header.m4 serial 17 +dnl Copyright (C) 2006-2022 Free Software Foundation, Inc. +dnl This file is free software; the Free Software Foundation +dnl gives unlimited permission to copy and/or distribute it, +dnl with or without modifications, as long as this notice is preserved. + +dnl From Derek Price. + +# gl_ABSOLUTE_HEADER(HEADER1 HEADER2 ...) +# --------------------------------------- +# Find the absolute name of a header file, testing first if the header exists. +# If the header were sys/inttypes.h, this macro would define +# ABSOLUTE_SYS_INTTYPES_H to the '""' quoted absolute name of sys/inttypes.h +# in config.h +# (e.g. '#define ABSOLUTE_SYS_INTTYPES_H "///usr/include/sys/inttypes.h"'). +# The three "///" are to pacify Sun C 5.8, which otherwise would say +# "warning: #include of /usr/include/... may be non-portable". +# Use '""', not '<>', so that the /// cannot be confused with a C99 comment. +# Note: This macro assumes that the header file is not empty after +# preprocessing, i.e. it does not only define preprocessor macros but also +# provides some type/enum definitions or function/variable declarations. +AC_DEFUN([gl_ABSOLUTE_HEADER], +[AC_REQUIRE([AC_CANONICAL_HOST]) +AC_LANG_PREPROC_REQUIRE()dnl +m4_foreach_w([gl_HEADER_NAME], [$1], + [AS_VAR_PUSHDEF([gl_absolute_header], + [gl_cv_absolute_]m4_defn([gl_HEADER_NAME]))dnl + AC_CACHE_CHECK([absolute name of <]m4_defn([gl_HEADER_NAME])[>], + [gl_absolute_header], + [AS_VAR_PUSHDEF([ac_header_exists], + [ac_cv_header_]m4_defn([gl_HEADER_NAME]))dnl + AC_CHECK_HEADERS_ONCE(m4_defn([gl_HEADER_NAME]))dnl + if test AS_VAR_GET([ac_header_exists]) = yes; then + gl_ABSOLUTE_HEADER_ONE(m4_defn([gl_HEADER_NAME])) + fi + AS_VAR_POPDEF([ac_header_exists])dnl + ])dnl + AC_DEFINE_UNQUOTED(AS_TR_CPP([ABSOLUTE_]m4_defn([gl_HEADER_NAME])), + ["AS_VAR_GET([gl_absolute_header])"], + [Define this to an absolute name of <]m4_defn([gl_HEADER_NAME])[>.]) + AS_VAR_POPDEF([gl_absolute_header])dnl +])dnl +])# gl_ABSOLUTE_HEADER + +# gl_ABSOLUTE_HEADER_ONE(HEADER) +# ------------------------------ +# Like gl_ABSOLUTE_HEADER, except that: +# - it assumes that the header exists, +# - it uses the current CPPFLAGS, +# - it does not cache the result, +# - it is silent. +AC_DEFUN([gl_ABSOLUTE_HEADER_ONE], +[ + AC_REQUIRE([AC_CANONICAL_HOST]) + AC_LANG_CONFTEST([AC_LANG_SOURCE([[#include <]]m4_dquote([$1])[[>]])]) + dnl AIX "xlc -E" and "cc -E" omit #line directives for header files + dnl that contain only a #include of other header files and no + dnl non-comment tokens of their own. This leads to a failure to + dnl detect the absolute name of <dirent.h>, <signal.h>, <poll.h> + dnl and others. The workaround is to force preservation of comments + dnl through option -C. This ensures all necessary #line directives + dnl are present. GCC supports option -C as well. + case "$host_os" in + aix*) gl_absname_cpp="$ac_cpp -C" ;; + *) gl_absname_cpp="$ac_cpp" ;; + esac +changequote(,) + case "$host_os" in + mingw*) + dnl For the sake of native Windows compilers (excluding gcc), + dnl treat backslash as a directory separator, like /. + dnl Actually, these compilers use a double-backslash as + dnl directory separator, inside the + dnl # line "filename" + dnl directives. + gl_dirsep_regex='[/\\]' + ;; + *) + gl_dirsep_regex='\/' + ;; + esac + dnl A sed expression that turns a string into a basic regular + dnl expression, for use within "/.../". + gl_make_literal_regex_sed='s,[]$^\\.*/[],\\&,g' + gl_header_literal_regex=`echo '$1' \ + | sed -e "$gl_make_literal_regex_sed"` + gl_absolute_header_sed="/${gl_dirsep_regex}${gl_header_literal_regex}/"'{ + s/.*"\(.*'"${gl_dirsep_regex}${gl_header_literal_regex}"'\)".*/\1/ + s|^/[^/]|//&| + p + q + }' +changequote([,]) + dnl eval is necessary to expand gl_absname_cpp. + dnl Ultrix and Pyramid sh refuse to redirect output of eval, + dnl so use subshell. + AS_VAR_SET([gl_cv_absolute_]AS_TR_SH([[$1]]), +[`(eval "$gl_absname_cpp conftest.$ac_ext") 2>&AS_MESSAGE_LOG_FD | + sed -n "$gl_absolute_header_sed"`]) +]) |