fix x86 Android builds

After tinkering with libstdc++ -> libc++, looks like we need this
warning again.  We already turn it on in Android's own x86 builds;
see gn_to_bp.py for that.

Change-Id: I7b7a76d1c22dd3f3b7712e9ce89b78d9a229a302
Reviewed-on: https://skia-review.googlesource.com/92360
Reviewed-by: Florin Malita <fmalita@chromium.org>
Commit-Queue: Mike Klein <mtklein@chromium.org>
1 file changed