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mirror of https://git.savannah.gnu.org/git/emacs.git synced 2024-11-23 07:19:15 +00:00
emacs/m4/lstat.m4
Paul Eggert 27e6afeb6f Merge from gnulib
This incorporates:
2015-04-24 file-has-acl: new module, split from acl
2015-04-24 manywarnings: add GCC 5.1 warnings
2015-04-21 lstat: fix cross-compilation 'ln -s' problem
2015-04-15 qacl: Simplify HP-UX acl_nontrivial check
2015-04-15 acl: On Linux, check for acls without libacl
2015-04-14 tempname: avoid unused parameter warnings (trivial)
* lib/acl-internal.c: New file, from gnulib.
* lib/file-has-acl.c: Remove; no longer imported from gnulib.
* lib/acl-internal.h, lib/gnulib.mk, lib/qcopy-acl.c, lib/tempname.c:
* m4/acl.m4, m4/gnulib-comp.m4, m4/lstat.m4, m4/manywarnings.m4:
Update from gnulib.
2015-04-24 22:41:56 -07:00

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# serial 27
# Copyright (C) 1997-2001, 2003-2015 Free Software Foundation, Inc.
#
# This file is free software; the Free Software Foundation
# gives unlimited permission to copy and/or distribute it,
# with or without modifications, as long as this notice is preserved.
dnl From Jim Meyering.
AC_DEFUN([gl_FUNC_LSTAT],
[
AC_REQUIRE([gl_SYS_STAT_H_DEFAULTS])
dnl If lstat does not exist, the replacement <sys/stat.h> does
dnl "#define lstat stat", and lstat.c is a no-op.
AC_CHECK_FUNCS_ONCE([lstat])
if test $ac_cv_func_lstat = yes; then
AC_REQUIRE([gl_FUNC_LSTAT_FOLLOWS_SLASHED_SYMLINK])
case "$gl_cv_func_lstat_dereferences_slashed_symlink" in
*no)
REPLACE_LSTAT=1
;;
esac
else
HAVE_LSTAT=0
fi
])
# Prerequisites of lib/lstat.c.
AC_DEFUN([gl_PREREQ_LSTAT], [:])
AC_DEFUN([gl_FUNC_LSTAT_FOLLOWS_SLASHED_SYMLINK],
[
dnl We don't use AC_FUNC_LSTAT_FOLLOWS_SLASHED_SYMLINK any more, because it
dnl is no longer maintained in Autoconf and because it invokes AC_LIBOBJ.
AC_CACHE_CHECK([whether lstat correctly handles trailing slash],
[gl_cv_func_lstat_dereferences_slashed_symlink],
[rm -f conftest.sym conftest.file
echo >conftest.file
AC_RUN_IFELSE(
[AC_LANG_PROGRAM(
[AC_INCLUDES_DEFAULT],
[[struct stat sbuf;
if (symlink ("conftest.file", "conftest.sym") != 0)
return 1;
/* Linux will dereference the symlink and fail, as required by
POSIX. That is better in the sense that it means we will not
have to compile and use the lstat wrapper. */
return lstat ("conftest.sym/", &sbuf) == 0;
]])],
[gl_cv_func_lstat_dereferences_slashed_symlink=yes],
[gl_cv_func_lstat_dereferences_slashed_symlink=no],
[case "$host_os" in
*-gnu*)
# Guess yes on glibc systems.
gl_cv_func_lstat_dereferences_slashed_symlink="guessing yes" ;;
*)
# If we don't know, assume the worst.
gl_cv_func_lstat_dereferences_slashed_symlink="guessing no" ;;
esac
])
rm -f conftest.sym conftest.file
])
case "$gl_cv_func_lstat_dereferences_slashed_symlink" in
*yes)
AC_DEFINE_UNQUOTED([LSTAT_FOLLOWS_SLASHED_SYMLINK], [1],
[Define to 1 if 'lstat' dereferences a symlink specified
with a trailing slash.])
;;
esac
])