Allows us to support 64 bit builds in the packaged project files.

BUG=angle:714

Change-Id: I7e2f57ec87d1c46b348a4821821d1e21be671e49
Reviewed-on: https://chromium-review.googlesource.com/210825Reviewed-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Shannon Woods <shannonwoods@chromium.org>
Tested-by: Geoff Lang <geofflang@chromium.org>