Add wrappers for ExitProcess, TerminateProcess

[Charles Wilson]

Dave Korn wrote:
>   As to the actual patch itself, it looks sane (just reading it by eye, I
> haven't tested it), and the design motivation seems reasonable.
[snip]
>   File-local extern declarations are pure evil, let alone function-local ones.
>  Why not fix this badness while you're touching it anyway?

'Cause I figured cgf did that for reasons beyond my ken.  What do you
suggest, moving the definition to globals.cc and the declaration(s) to
winsup.h?

--
Chuck