[src/trunk]: src/sys/lib/libkern If GCC 4.0 or later, use __builtin_offsetof ...

[matt <matt%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/fa18a73ad624
branches:  trunk
changeset: 766956:fa18a73ad624
user:      matt <matt%NetBSD.org@localhost>
date:      Tue Jul 05 01:56:45 2011 +0000

description:
If GCC 4.0 or later, use __builtin_offsetof for offsetof.
This make GCC 4.5 with offsetof in mbuf.h and kern_cpu.c

diffstat:

 sys/lib/libkern/libkern.h |  6 +++++-
 1 files changed, 5 insertions(+), 1 deletions(-)

diffs (23 lines):

diff -r 53e087501d9e -r fa18a73ad624 sys/lib/libkern/libkern.h
--- a/sys/lib/libkern/libkern.h Mon Jul 04 23:37:30 2011 +0000
+++ b/sys/lib/libkern/libkern.h Tue Jul 05 01:56:45 2011 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: libkern.h,v 1.97 2011/02/19 02:02:14 matt Exp $        */
+/*     $NetBSD: libkern.h,v 1.98 2011/07/05 01:56:45 matt Exp $        */
 
 /*-
  * Copyright (c) 1992, 1993
@@ -245,9 +245,13 @@
 #define SMALL_RANDOM
 
 #ifndef offsetof
+#if __GNUC_PREREQ__(4, 0)
+#define offsetof(type, member) __builtin_offsetof(type, member)
+#else
 #define        offsetof(type, member) \
     ((size_t)(unsigned long)(&(((type *)0)->member)))
 #endif
+#endif
 
 #define        MTPRNG_RLEN             624
 struct mtprng_state {