Reapply 201734 but with appropriate gcc compatibility

Reapply 201734 but with appropriate gcc compatibility
Because GCC incorrectly defines _mm_prefetch to take anything that casts
to void*, people have started using that behavior.  The previous patch
that made _mm_prefetch actually take a const char * broke compatibility
with existing code.  This update to the patch leaves the macro that
defines _mm_prefetch with the (void*) cast when _MSC_VER is not defined.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@201901 91177308-0d34-0410-b5e6-96231b3b80d8