Teach the warning about non-POD memset/memcpy/memmove to deal with the

__builtin_ versions of these functions as well as the normal function
versions, so that it works on platforms where memset/memcpy/memmove
are macros that map down to the builtins (e.g., Darwin). Fixes
<rdar://problem/9372688>.

llvm-svn: 133173