message: LLVM API updates.
diff: @@ -47,7 +47,7 @@ template <typename T> class ArrayRef;
  template <typename T> class MutableArrayRef;
  template <typename T> class TinyPtrVector;
  template <typename T> class Optional;
  -template <typename PT1, typename PT2> class PointerUnion;
  +template <typename... PT> class PointerUnion;
  namespace detail {
  template <typename KeyT, typename ValueT> struct DenseMapPair;
  }
  