Avoid re-definition of STDC symbols, needed for my ffmpeg work.
Avoid re-definition of STDC symbols, needed for my ffmpeg work.

See changes to build/common.gypi in https://codereview.chromium.org/11364077/

BUG=118986, 91970

Review URL: https://codereview.appspot.com/6810088
Patch from Paweł Hajdan, Jr. <phajdan.jr@chromium.org>.

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