New gcc plugin: stackleak

- Introduces the stackleak gcc plugin ported from grsecurity by Alexander
  Popov, with x86 and arm64 support.
arm64: Drop unneeded stackleak_check_alloca()

Drop stackleak_check_alloca() for arm64 since the STACKLEAK gcc plugin now
doesn't track stack depth overflow caused by alloca().

Signed-off-by: Alexander Popov <alex.popov@linux.com>
Tested-by: Laura Abbott <labbott@redhat.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
1 file changed