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emacs/m4/readlink.m4
Paul Eggert 78669517dc Update from Gnulib
This incorporates:
2019-09-22 Update some URLs
2019-09-15 fcntl-h: fix compilation error of creat.c on MSVC
2019-09-15 creat: new module
2019-09-15 access: new module
2019-09-09 Add option to assume best, not worst, when cross-compiling.
* build-aux/config.guess, build-aux/config.sub, doc/misc/texinfo.tex:
* lib/careadlinkat.c, lib/careadlinkat.h, lib/count-leading-zeros.h:
* lib/count-trailing-zeros.h, lib/diffseq.h, lib/fcntl.in.h:
* lib/ftoastr.c, lib/get-permissions.c:
* lib/ieee754.in.h, lib/inttypes.in.h, lib/mktime.c, lib/open.c:
* lib/pathmax.h, lib/pipe2.c, lib/stddef.in.h, lib/stdint.in.h:
* lib/stdlib.in.h, lib/str-two-way.h, lib/string.in.h, lib/time.in.h:
* lib/timegm.c, lib/unistd.in.h, m4/canonicalize.m4:
* m4/extern-inline.m4, m4/fcntl_h.m4, m4/fdopendir.m4:
* m4/getgroups.m4, m4/getopt.m4, m4/gettimeofday.m4:
* m4/gnulib-common.m4, m4/largefile.m4:
* m4/lstat.m4, m4/memmem.m4, m4/mktime.m4, m4/nocrash.m4, m4/open.m4:
* m4/pselect.m4, m4/putenv.m4, m4/readlink.m4, m4/regex.m4:
* m4/symlink.m4, m4/unistd_h.m4, m4/utimens.m4, m4/utimes.m4:
Copy from Gnulib.
* lib/gnulib.mk.in, m4/gnulib-comp.m4: Regenerate.
* m4/open-slash.m4: New file, copied from Gnulib.
2019-09-22 23:51:44 -07:00

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# readlink.m4 serial 15
dnl Copyright (C) 2003, 2007, 2009-2019 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.
AC_DEFUN([gl_FUNC_READLINK],
[
AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
AC_CHECK_FUNCS_ONCE([readlink])
if test $ac_cv_func_readlink = no; then
HAVE_READLINK=0
else
AC_CACHE_CHECK([whether readlink signature is correct],
[gl_cv_decl_readlink_works],
[AC_COMPILE_IFELSE(
[AC_LANG_PROGRAM(
[[#include <unistd.h>
/* Cause compilation failure if original declaration has wrong type. */
ssize_t readlink (const char *, char *, size_t);]])],
[gl_cv_decl_readlink_works=yes], [gl_cv_decl_readlink_works=no])])
dnl Solaris 9 ignores trailing slash.
dnl FreeBSD 7.2 dereferences only one level of links with trailing slash.
AC_CACHE_CHECK([whether readlink handles trailing slash correctly],
[gl_cv_func_readlink_works],
[# We have readlink, so assume ln -s works.
ln -s conftest.no-such conftest.link
ln -s conftest.link conftest.lnk2
AC_RUN_IFELSE(
[AC_LANG_PROGRAM(
[[#include <unistd.h>
]], [[char buf[20];
return readlink ("conftest.lnk2/", buf, sizeof buf) != -1;]])],
[gl_cv_func_readlink_works=yes], [gl_cv_func_readlink_works=no],
[case "$host_os" in
# Guess yes on Linux systems.
linux-* | linux) gl_cv_func_readlink_works="guessing yes" ;;
# Guess yes on glibc systems.
*-gnu* | gnu*) gl_cv_func_readlink_works="guessing yes" ;;
# If we don't know, obey --enable-cross-guesses.
*) gl_cv_func_readlink_works="$gl_cross_guess_normal" ;;
esac
])
rm -f conftest.link conftest.lnk2])
case "$gl_cv_func_readlink_works" in
*yes)
if test "$gl_cv_decl_readlink_works" != yes; then
REPLACE_READLINK=1
fi
;;
*)
AC_DEFINE([READLINK_TRAILING_SLASH_BUG], [1], [Define to 1 if readlink
fails to recognize a trailing slash.])
REPLACE_READLINK=1
;;
esac
fi
])
# Like gl_FUNC_READLINK, except prepare for separate compilation
# (no REPLACE_READLINK, no AC_LIBOBJ).
AC_DEFUN([gl_FUNC_READLINK_SEPARATE],
[
AC_CHECK_FUNCS_ONCE([readlink])
gl_PREREQ_READLINK
])
# Prerequisites of lib/readlink.c.
AC_DEFUN([gl_PREREQ_READLINK],
[
:
])