build for Chromecast with clang

I don't think this switches to libc++... just from GCC to Clang.

Change-Id: I755464161d030668e34ab79f4a77d9807ddc8e3f
Reviewed-on: https://skia-review.googlesource.com/131520
Reviewed-by: Brian Salomon <bsalomon@google.com>
Reviewed-by: Kevin Lubick <kjlubick@google.com>
Commit-Queue: Mike Klein <mtklein@google.com>
2 files changed