Pass -Wno-c++11-extensions to clang front end
Pass -Wno-c++11-extensions to clang front end

The chromium base/ code has changed to use OVERRIDE more.
This macro is defined to the "override" keyword under #ifdef __clang__.
Since that keyword is not part of the -std=gnu++98 feature set we build
for, it gets a warning (fatal under -Werror) unless we suppress it.

BUG= none
TEST= none

R=jvoung@google.com,pdox@google.com

Review URL: http://codereview.chromium.org/8672002

git-svn-id: 721b910a23eff8a86f00c8fd261a7587cddf18f8@7269 fcba33aa-ac0c-11dd-b9e7-8d5594d729c2

sbc100/native_client,sbc100/native_client,nacl-webkit/native_client,sbc100/native_client,nacl-webkit/native_client,sbc100/native_client,sbc100/native_client,nacl-webkit/native_client,nacl-webkit/native_client,nacl-webkit/native_client,sbc100/native_client