# Define AC_USE_SYSTEM_EXTENSIONS only if it was previously undefined.
# This is needed to configure correctly with newer versions of autoconf.

diff -urN cpio-2.8.orig/m4/extensions.m4 cpio-2.8/m4/extensions.m4
--- cpio-2.8.orig/m4/extensions.m4	2006-10-12 04:34:45.000000000 -0700
+++ cpio-2.8/m4/extensions.m4	2010-07-23 14:37:36.000000000 -0700
@@ -1,4 +1,4 @@
-# serial 4  -*- Autoconf -*-
+# serial 5  -*- Autoconf -*-
 # Enable extensions on systems that normally disable them.
 
 # Copyright (C) 2003, 2006 Free Software Foundation, Inc.
@@ -16,6 +16,7 @@
 # ------------------------
 # Enable extensions on systems that normally disable them,
 # typically due to standards-conformance issues.
+m4_ifdef([AC_USE_SYSTEM_EXTENSIONS], [], [
 AC_DEFUN([AC_USE_SYSTEM_EXTENSIONS],
 [
   AC_BEFORE([$0], [AC_COMPILE_IFELSE])
@@ -48,7 +49,7 @@
     AC_DEFINE([__EXTENSIONS__])
   AC_DEFINE([_POSIX_PTHREAD_SEMANTICS])
   AC_DEFINE([_TANDEM_SOURCE])
-])
+])])
 
 # gl_USE_SYSTEM_EXTENSIONS
 # ------------------------
