PATCH: Add __frame_state_for for gcc 3.0.1

[Joe Buck]

HJ writes:
> > ... That is _Unwind_Find_FDE cannot find the frame if you
> > have mixed g++ v2 and g++ v3 frames. Do we really want to modify
> > _Unwind_Find_FDE to support such a thing? I think the best we can
> > do may be detect such a condition and issue a fatal error message.

Jakub writes:
> It IMHO must work (although one cannot mix pre-G++ 3.0 and G++ 3.0 C++
> libraries together, one should be able to mix G++ 3.0 C++ libraries with
> pre-GCC 3.0 C libraries and vice versa, and C libraries can have unwinding
> info). So it needs to be debugged why it cannot find it.

I'm not convinced.  Rather, while I'll agree that, all things being equal,
it would be nice if it worked, failure to work is a low-priority bug
(especially if HJ's idea of detecting the condition and issuing an
error can be done).  We have bigger problems.

Which C libraries in common use have unwinding info?