Merge from origin/emacs-24

[gnu-emacs] / m4 / readlinkat.m4

diff --git a/m4/readlinkat.m4 b/m4/readlinkat.m4
index b2ff40dcb027bc6bffc3db68dad4a5c3ec566e85..f9ed9436af62b88a147804ebd9d05a99056e3ab6 100644 (file)
--- a/m4/readlinkat.m4
+++ b/m4/readlinkat.m4
@@ -1,7 +1,7 @@
-# serial 3
+# serial 4
 # See if we need to provide readlinkat replacement.
 
-dnl Copyright (C) 2009-2013 Free Software Foundation, Inc.
+dnl Copyright (C) 2009-2014 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.
@@ -15,5 +15,18 @@ AC_DEFUN([gl_FUNC_READLINKAT],
   AC_CHECK_FUNCS_ONCE([readlinkat])
   if test $ac_cv_func_readlinkat = no; then
     HAVE_READLINKAT=0
+  else
+    AC_CACHE_CHECK([whether readlinkat signature is correct],
+      [gl_cv_decl_readlinkat_works],
+      [AC_COMPILE_IFELSE(
+         [AC_LANG_PROGRAM(
+           [[#include <unistd.h>
+             /* Check whether original declaration has correct type.  */
+             ssize_t readlinkat (int, char const *, char *, size_t);]])],
+         [gl_cv_decl_readlinkat_works=yes],
+         [gl_cv_decl_readlinkat_works=no])])
+    if test "$gl_cv_decl_readlink_works" != yes; then
+      REPLACE_READLINKAT=1
+    fi
   fi
 ])