enable -Werror by default

People keep adding code with warnings, so enable -Werror to prevent that.

BUG=None
TEST=`FEATURES=test emerge-x86-alex platform2` passes
TEST=`FEATURES=test emerge-daisy platform2` passes
TEST=`FEATURES=test emerge-lumpy platform2` passes

Change-Id: Iea0e739b6249eaf70c5263504e08bbdc532f3afe
Reviewed-on: https://chromium-review.googlesource.com/180921
Reviewed-by: Daniel Erat <derat@chromium.org>
Commit-Queue: Mike Frysinger <vapier@chromium.org>
Tested-by: Mike Frysinger <vapier@chromium.org>
1 file changed