builtins.py doesn't completely resolve "<*mmintrin.h>" when using GCC(4.9.2) libs

Hi all,

It seems like that new symbols are added hence not handled by builtins.py
found here:
http://clang.llvm.org/compatibility.html#vector_builtins
<http://clang.llvm.org/compatibility.html#vector_builtins&gt;

Compiler output--

mmintrin_diagnostic.txt
<http://clang-developers.42468.n3.nabble.com/file/n4043672/mmintrin_diagnostic.txt&gt;