Import upstream version 1.29

[debian/tar] / m4 / readlinkat.m4

diff --git a/m4/readlinkat.m4 b/m4/readlinkat.m4
index 65c0689c114b88d5d0f71435d3bfa22e7a3df083..3477602a14faedb08a6f7a89627eefd955294773 100644 (file)
--- a/m4/readlinkat.m4
+++ b/m4/readlinkat.m4
@@ -1,7 +1,7 @@
-# serial 3
+# serial 5
 # See if we need to provide readlinkat replacement.
 
-dnl Copyright (C) 2009-2014 Free Software Foundation, Inc.
+dnl Copyright (C) 2009-2015 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.
@@ -13,7 +13,30 @@ AC_DEFUN([gl_FUNC_READLINKAT],
   AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
   AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
   AC_CHECK_FUNCS_ONCE([readlinkat])
+  AC_REQUIRE([gl_FUNC_READLINK])
   if test $ac_cv_func_readlinkat = no; then
     HAVE_READLINKAT=0
+  else
+    AC_CACHE_CHECK([whether readlinkat signature is correct],
+      [gl_cv_decl_readlinkat_works],
+      [AC_COMPILE_IFELSE(
+         [AC_LANG_PROGRAM(
+           [[#include <unistd.h>
+             /* Check whether original declaration has correct type.  */
+             ssize_t readlinkat (int, char const *, char *, size_t);]])],
+         [gl_cv_decl_readlinkat_works=yes],
+         [gl_cv_decl_readlinkat_works=no])])
+    # Assume readinkat has the same trailing slash bug as readlink,
+    # as is the case on Mac Os X 10.10
+    case "$gl_cv_func_readlink_works" in
+      *yes)
+        if test "$gl_cv_decl_readlinkat_works" != yes; then
+          REPLACE_READLINKAT=1
+        fi
+        ;;
+      *)
+        REPLACE_READLINKAT=1
+        ;;
+    esac
   fi
 ])