util/abuild: Add --asserts flag

This enables fatal asserts, which can be useful to get better
diagnostics by the build tools (both compilers and static analysis.)

Change-Id: I1e1653f465fe1f545878d6eec83b8645dc17d9cb
Signed-off-by: Patrick Georgi <pgeorgi@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/34567
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Martin Roth <martinroth@google.com>
Reviewed-by: Jacob Garber <jgarber1@ualberta.ca>

util/abuild/abuild

@@ -677,6 +677,9 @@ while true ; do
 			SCANBUILD_ARGS=${SCANBUILD_ARGS:-'-k'}
 			configoptions="${configoptions}CONFIG_FATAL_ASSERTS=y\n"
 			;;
+		--asserts)	shift
+			configoptions="${configoptions}CONFIG_FATAL_ASSERTS=y\n"
+			;;
 		-y|--ccache)    shift
 			customizing="${customizing}, ccache"
 			configoptions="${configoptions}CONFIG_CCACHE=y\n"