emacs/m4/symlink.m4

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# symlink.m4
# serial 10
dnl Copyright (C) 2009-2024 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
dnl with or without modifications, as long as this notice is preserved.
# See if we need to provide symlink replacement.
# Written by Eric Blake.
AC_DEFUN([gl_FUNC_SYMLINK],
[
AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
AC_CHECK_FUNCS_ONCE([symlink])
dnl The best we can do on mingw is provide a dummy that always fails, so
dnl that compilation can proceed with fewer ifdefs. On FreeBSD 7.2, AIX 7.1,
dnl and Solaris 9, we want to fix a bug with trailing slash handling.
if test $ac_cv_func_symlink = no; then
HAVE_SYMLINK=0
else
AC_CACHE_CHECK([whether symlink handles trailing slash correctly],
[gl_cv_func_symlink_works],
[AC_RUN_IFELSE(
[AC_LANG_PROGRAM(
[[#include <unistd.h>
]],
[[int result = 0;
if (!symlink ("a", "conftest.link/"))
result |= 1;
if (symlink ("conftest.f", "conftest.lnk2"))
result |= 2;
else if (!symlink ("a", "conftest.lnk2/"))
result |= 4;
return result;
]])],
[gl_cv_func_symlink_works=yes], [gl_cv_func_symlink_works=no],
[case "$host_os" in
# Guess yes on Linux systems.
linux-* | linux) gl_cv_func_symlink_works="guessing yes" ;;
# Guess yes on systems that emulate the Linux system calls.
midipix*) gl_cv_func_symlink_works="guessing yes" ;;
# Guess yes on glibc systems.
*-gnu* | gnu*) gl_cv_func_symlink_works="guessing yes" ;;
# If we don't know, obey --enable-cross-guesses.
*) gl_cv_func_symlink_works="$gl_cross_guess_normal" ;;
esac
])
rm -f conftest.f conftest.link conftest.lnk2])
case "$gl_cv_func_symlink_works" in
*yes) ;;
*)
REPLACE_SYMLINK=1
;;
esac
fi
])