gcc comptability: silent -fdefer-pop & -fno-defer-pop 

Reviewers: rafael, rnk

Reviewed By: rnk

Subscribers: rnk, cfe-commits

Differential Revision: http://reviews.llvm.org/D4357

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@212327 91177308-0d34-0410-b5e6-96231b3b80d8