Temporarily revert r151609, which enabled a new warning for LLVM and
Clang builds. The detection logic for compilers that support the warning
isn't working. Rafael is going to investigate it, but didn't want people
to have to wade through build spam until then.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151649 91177308-0d34-0410-b5e6-96231b3b80d8
9 files changed