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-rw-r--r--m4/link.m458
1 files changed, 58 insertions, 0 deletions
diff --git a/m4/link.m4 b/m4/link.m4
new file mode 100644
index 0000000..154b9d0
--- /dev/null
+++ b/m4/link.m4
@@ -0,0 +1,58 @@
+# link.m4 serial 11
+dnl Copyright (C) 2009-2022 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_LINK],
+[
+ AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
+ AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+ AC_CHECK_FUNCS_ONCE([link])
+ if test $ac_cv_func_link = no; then
+ HAVE_LINK=0
+ else
+ AC_CACHE_CHECK([whether link obeys POSIX],
+ [gl_cv_func_link_works],
+ [touch conftest.a
+ # Assume that if we have lstat, we can also check symlinks.
+ if test $ac_cv_func_lstat = yes; then
+ ln -s conftest.a conftest.lnk
+ fi
+ AC_RUN_IFELSE(
+ [AC_LANG_PROGRAM(
+ [[#include <unistd.h>
+ #include <stdio.h>
+ ]],
+ [[int result = 0;
+ if (!link ("conftest.a", "conftest.b/"))
+ result |= 1;
+#if HAVE_LSTAT
+ if (!link ("conftest.lnk/", "conftest.b"))
+ result |= 2;
+ if (rename ("conftest.a", "conftest.b"))
+ result |= 4;
+ if (!link ("conftest.b", "conftest.lnk"))
+ result |= 8;
+#endif
+ return result;
+ ]])],
+ [gl_cv_func_link_works=yes], [gl_cv_func_link_works=no],
+ [case "$host_os" in
+ # Guess yes on Linux systems.
+ linux-* | linux) gl_cv_func_link_works="guessing yes" ;;
+ # Guess yes on glibc systems.
+ *-gnu* | gnu*) gl_cv_func_link_works="guessing yes" ;;
+ # If we don't know, obey --enable-cross-guesses.
+ *) gl_cv_func_link_works="$gl_cross_guess_normal" ;;
+ esac
+ ])
+ rm -f conftest.a conftest.b conftest.lnk])
+ case "$gl_cv_func_link_works" in
+ *yes) ;;
+ *)
+ REPLACE_LINK=1
+ ;;
+ esac
+ fi
+])