We can include Makefiles in the ignore list, and need a few extra
flags to fix the GCC build on Linux.

BUG=angle:563

Change-Id: Iacd386359f0c0d9bb87ddc544dd8b4da2cb8fee0
Reviewed-on: https://chromium-review.googlesource.com/186902Reviewed-by: Shannon Woods <shannonwoods@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Tested-by: Jamie Madill <jmadill@chromium.org>