Add 178663 back.

http://lab.llvm.org:8011/builders/clang-x86_64-darwin10-gdb went back green
before it processed the reverted 178663, so it could not have been the culprit.

Revert "Revert 178663."

This reverts commit 4f8a3eb2ce5d4ba422483439e20c8cbb4d953a41.

llvm-svn: 178682