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# serial 2
# See if we need to provide linkat replacement.
dnl Copyright (C) 2009-2010 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.
# Written by Eric Blake.
AC_DEFUN([gl_FUNC_LINKAT],
[
AC_REQUIRE([gl_FUNC_OPENAT])
AC_REQUIRE([gl_FUNC_LINK])
AC_REQUIRE([gl_FUNC_LINK_FOLLOWS_SYMLINK])
AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
AC_CHECK_FUNCS_ONCE([linkat symlink])
AC_CHECK_HEADERS_ONCE([sys/param.h])
if test $ac_cv_func_linkat = no; then
HAVE_LINKAT=0
AC_LIBOBJ([linkat])
AC_LIBOBJ([at-func2])
else
AC_CACHE_CHECK([whether linkat(,AT_SYMLINK_FOLLOW) works],
[gl_cv_func_linkat_follow],
[rm -rf conftest.f1 conftest.f2
touch conftest.f1
AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
#include <fcntl.h>
#include <unistd.h>
#ifdef __linux__
/* Linux added linkat in 2.6.16, but did not add AT_SYMLINK_FOLLOW
until 2.6.18. Always replace linkat to support older kernels. */
choke me
#endif
]], [return linkat (AT_FDCWD, "conftest.f1", AT_FDCWD, "conftest.f2",
AT_SYMLINK_FOLLOW);])],
[gl_cv_func_linkat_follow=yes],
[gl_cv_func_linkat_follow="need runtime check"])
rm -rf conftest.f1 conftest.f2])
if test "$gl_cv_func_linkat_follow" != yes; then
REPLACE_LINKAT=1
AC_LIBOBJ([linkat])
fi
fi
])
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