include/linux/compiler-gcc4.h: Fix build bug - gcc-4.0.2 doesn't understand __builtin_object_size

Maybe 4.1.0 doesn't too, but this fixed it for me.

Caused by:

 4a312769: x86: Turn the copy_from_user check into an (optional) compile time warning
 9f0cf4ad: x86: Use __builtin_object_size() to validate the buffer size for copy_from_user()

Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
LKML-Reference: <200910090724.n997OQl6013538@imap1.linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>