libpayload: Add compiler switch

clang is totally untested, but it mirrors coreboot now.

Change-Id: I0e13ff8bba2007159a4a795ca07d187504b606b2
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Reviewed-on: http://review.coreboot.org/10800
Tested-by: build bot (Jenkins)
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
2 files changed