Enable clang unsafe buffers warnings for ANGLE. Then suppress all directories containing C++ source code to get a good initial state. Bug: b/436880895 Change-Id: Ib1e23015896078af7a1bec7d22cafdcd1fc713e2 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/6854299 Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org> Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org> Reviewed-by: Geoff Lang <geofflang@chromium.org>