patch <bits/localefwd.h> with -fno-exceptions

[Dirk Mueller]

> This seems the most sane to me, it's a macro-less and debuggable
> solution that allows users to painlessly transition to a world where
> exception codegen issues are less of an issue, and I'd be willing to
> do this work. Jason, can you meet me half-way? What are your thoughts?


I'd be happy to help to add these inlines/macros everywhere or test patches. 
Just tell me the way you want them and I'll be happy to prepare a patch. 


Thanks, Dirk.