md5, sha1, sha256, sha512: add gl_SET_CRYPTO_CHECK_DEFAULT

[gnulib.git] / m4 / link.m4

diff --git a/m4/link.m4 b/m4/link.m4
index 349d537..7cc0ceb 100644 (file)
--- a/m4/link.m4
+++ b/m4/link.m4
@@ -1,5 +1,5 @@
-# link.m4 serial 1
-dnl Copyright (C) 2009 Free Software Foundation, Inc.
+# link.m4 serial 8
+dnl Copyright (C) 2009-2013 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.
@@ -7,13 +7,49 @@ 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
-    AC_LIBOBJ([link])
-    gl_PREREQ_LINK
+  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 $ac_cv_func_lstat = yes; then
+         ln -s conftest.a conftest.lnk
+       fi
+       AC_RUN_IFELSE(
+         [AC_LANG_PROGRAM(
+           [[#include <unistd.h>
+           ]],
+           [[int result = 0;
+             if (!link ("conftest.a", "conftest.b/"))
+               result |= 1;
+#if HAVE_LSTAT
+             if (!link ("conftest.lnk/", "conftest.b"))
+               result |= 2;
+             if (rename ("conftest.a", "conftest.b"))
+               result |= 4;
+             if (!link ("conftest.b", "conftest.lnk"))
+               result |= 8;
+#endif
+             return result;
+           ]])],
+         [gl_cv_func_link_works=yes], [gl_cv_func_link_works=no],
+         [case "$host_os" in
+                    # Guess yes on glibc systems.
+            *-gnu*) gl_cv_func_link_works="guessing yes" ;;
+                    # If we don't know, assume the worst.
+            *)      gl_cv_func_link_works="guessing no" ;;
+          esac
+         ])
+       rm -f conftest.a conftest.b conftest.lnk])
+    case "$gl_cv_func_link_works" in
+      *yes) ;;
+      *)
+        REPLACE_LINK=1
+        ;;
+    esac
   fi
 ])
-
-# Prerequisites of lib/link.c.
-AC_DEFUN([gl_PREREQ_LINK], [:])