util/xcompile: Use new GCC's warning options only if supported

Wflex-array-member-not-at-end & Wcalloc-transposed-args are
not supported when using GCC older than GCC-14.
Use them only when supported.

Change-Id: I11c1e729569c8130bd254a10454c5066a72974d6
Signed-off-by: Elyes Haouas <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/82785
Reviewed-by: Nico Huber <nico.h@gmx.de>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Felix Singer <service+coreboot-gerrit@felixsinger.de>

0 files changed, 0 insertions, 0 deletions