http://sources.redhat.com/git/gitweb.cgi?p=glibc.git;a=commitdiff;h=6e502e19455c6110dd4487d91b7b7d6d8121f9ba

commit 6e502e19455c6110dd4487d91b7b7d6d8121f9ba
Author: Ulrich Drepper <drepper@gmail.com>
Date:   Wed Jun 22 08:32:55 2011 -0400

    Clean up after kernel sigcontext header mess


2011-06-21  Andreas Jaeger  <aj@suse.de>

	* sysdeps/unix/sysv/linux/bits/sigcontext.h: Fix definition of
	NULL after inclusion of kernel headers.


diff --git a/sysdeps/unix/sysv/linux/bits/sigcontext.h b/sysdeps/unix/sysv/linux/bits/sigcontext.h
index 67dcf94..0f5b607 100644
--- a/sysdeps/unix/sysv/linux/bits/sigcontext.h
+++ b/sysdeps/unix/sysv/linux/bits/sigcontext.h
@@ -1,4 +1,4 @@
-/* Copyright (C) 1996, 1997, 1998 Free Software Foundation, Inc.
+/* Copyright (C) 1996, 1997, 1998, 2011 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
    The GNU C Library is free software; you can redistribute it and/or
@@ -26,4 +26,8 @@
 # define sigcontext_struct sigcontext
 
 # include <asm/sigcontext.h>
+
+/* The Linux kernel headers redefine NULL wrongly, so cleanup afterwards.  */
+# define __need_NULL
+# include <stddef.h>
 #endif