The old logic made the cfi build fail on each clang update.

Bug: chromium:726584
Change-Id: Ia24181d3bc92eb18116c2ac2b42ac2c68f02ce25
Reviewed-on: https://chromium-review.googlesource.com/518185Reviewed-by: Jochen Eisinger <jochen@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#45601}