Feed Clang a pragma to ignore -Wc++11-extensions to let it build Skia on Mac.
Feed Clang a pragma to ignore -Wc++11-extensions to let it build Skia on Mac.

Tested:
CXX=clang++ ./gyp_skia && ninja -C out/Debug && CXX=G++ ./gyp_skia && ninja -C out/Debug && echo "ok"

Got to ok.

BUG=
R=bungeman@google.com

Author: mtklein@google.com

Review URL: https://chromiumcodereview.appspot.com/14365009

csulmone/skia,csulmone/skia,csulmone/skia,csulmone/skia