Some architectures (e.g. Alpha) do not support the
-fstack-protector-all compiler option and the use of the option
with -Werror causes the compiler to abort and the build fails.

Test that the compiler supports -fstack-protector-all before
inclusion in CFLAGS.
Signed-off-by: Michael Cree <mcree@orcon.net.nz>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <20091111074302.GA3728@omega>
Signed-off-by: Ingo Molnar <mingo@elte.hu>