Disable -Wsentinel warning for Linux 32-bit builds.

BUG=chromium:644167
NOTRY=True

Review-Url: https://codereview.webrtc.org/2316943002
Cr-Original-Commit-Position: refs/heads/master@{#14099}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: d4626e5f1e1923072fe242539e227d507c91b3d4
1 file changed