Use -Werror at link time
Use -Werror at link time

This makes the SCons build use -Werror in the linking stage for both
trusted (non-Windows) code and untrusted code.  At least with Clang,
this catches some snafus that can otherwise go silently unnoticed.

BUG= https://code.google.com/p/nativeclient/issues/detail?id=4147
TEST= trybots
R=dschuff@chromium.org

Review URL: https://codereview.chromium.org/1094893002

sbc100/native_client,sbc100/native_client,sbc100/native_client,sbc100/native_client,sbc100/native_client,sbc100/native_client