PATCH RFA: Avoid enum bitfield in C++ frontend

[Jason Merrill]

Ian Lance Taylor wrote:
> This is how I think the code looks best--I don't see a need for a
> special type to hold this combination of bitfields.  However, it would
> be a smaller change to let the C++ frontend continue to use
> tsubst_flags_t, and simply do "typedef int tsubst_flags_t".  If the C++
> frontend maintainers would prefer that patch, I can do that instead.

I think I would prefer that; the typedef provides documentation about 
what the complain parameter means.  If it goes away we'd need to add a 
note to the comments before all the functions.

Jason