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emacs/m4/lstat.m4
Paul Eggert 3128d5d10e Merge from gnulib
This incorporates:
2017-07-13 Improve cross-compilation guesses for native Windows
2017-07-11 More systematic m4 quoting and indentation
2017-07-10 Make sure $host and $host_os are defined when used
2017-07-03 stdioext: Port to OpenVMS
2017-06-24 xalloc-oversized: port to icc
* doc/misc/texinfo.tex, lib/fpending.c, lib/stdio-impl.h:
* lib/xalloc-oversized.h, m4/dirfd.m4, m4/gettimeofday.m4:
* m4/lstat.m4, m4/mktime.m4, m4/pselect.m4, m4/putenv.m4:
* m4/stdint.m4, m4/strtoimax.m4, m4/utimes.m4:
Copy from Gnulib.
2017-07-13 19:24:49 -07:00

76 lines
2.6 KiB
Plaintext

# serial 29
# Copyright (C) 1997-2001, 2003-2017 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dnl is no longer maintained in Autoconf and because it invokes AC_LIBOBJ.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_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
AC_CACHE_CHECK([whether lstat correctly handles trailing slash],
[gl_cv_func_lstat_dereferences_slashed_symlink],
[rm -f conftest.sym conftest.file
echo >conftest.file
AC_RUN_IFELSE(
[AC_LANG_PROGRAM(
[AC_INCLUDES_DEFAULT],
[[struct stat sbuf;
if (symlink ("conftest.file", "conftest.sym") != 0)
return 1;
/* Linux will dereference the symlink and fail, as required by
POSIX. That is better in the sense that it means we will not
have to compile and use the lstat wrapper. */
return lstat ("conftest.sym/", &sbuf) == 0;
]])],
[gl_cv_func_lstat_dereferences_slashed_symlink=yes],
[gl_cv_func_lstat_dereferences_slashed_symlink=no],
[case "$host_os" in
*-gnu*)
# Guess yes on glibc systems.
gl_cv_func_lstat_dereferences_slashed_symlink="guessing yes" ;;
mingw*)
# Guess no on native Windows.
gl_cv_func_lstat_dereferences_slashed_symlink="guessing no" ;;
*)
# If we don't know, assume the worst.
gl_cv_func_lstat_dereferences_slashed_symlink="guessing no" ;;
esac
])
rm -f conftest.sym conftest.file
])
case "$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
])