For PR811:

For PR811:
Don't both with the "C" and "cc" extensions as they aren't common and they
the "C" extension conflicts with the "c" extension on operating systems
that have case insensitive file names.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@28899 91177308-0d34-0410-b5e6-96231b3b80d8