Compiling an allyesconfig kernel straight with a gcc 4.0 snapshot
gives nearly 10k new warnings like:

warning: pointer targets in passing argument 5 of `cpuid' differ in signedness

Since the sheer number of these warnings was too much even for the
most determined kernel janitors (I actually asked ;-) and I don't
think it's a very serious issue to have these mismatches I submitted
an new option to gcc to disable it. It was incorporated in gcc mainline
now.

This patch makes the kernel compilation use it. There are still
quite a lot of new warnings with 4.0 (mostly about uninitialized variables),
but the compile log looks much nicer nnow.
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>