car globals: add "used" attribute

Otherwise clang feels free to optimize away that variable
(somewhat) and revive it in a different form inside .bss.

They probably have the language lawyery excuse for why
that's perfectly legal, so let's play it safe.
(relevant URL, sorry ron: http://llvm.org/bugs/show_bug.cgi?id=9520)

Change-Id: I603312ceea7207088dd29453cc8fb8f48c31af21
Signed-off-by: Patrick Georgi <patrick@georgi-clan.de>
Reviewed-on: http://review.coreboot.org/7357
Reviewed-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>
Tested-by: build bot (Jenkins)

0 files changed, 0 insertions, 0 deletions