The result of the Microsoft __uuidof operator must be considered a global lvalue...

The result of the Microsoft __uuidof operator must be considered a global lvalue during constant expression evaluation.
Otherwise we would get this error in C++11 mode (because of a recent change):
   error: non-type template argument of type 'const _GUID *' is not a constant expression

For code like:
template <const GUID* g = &__uuidof(struct_with_uuid)>
class COM_CLASS { };

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@154790 91177308-0d34-0410-b5e6-96231b3b80d8