IS_TRAPPED_INTERNALVAR

[Andrew Cagney]

> I just found this exquisitely useful hook.
> [It's _amazing_ what I _still_ keep finding in the tools. :-)]
> 
> The number of places it appears in the sources is
> small and localized so if it goes away it won't hurt much,
> but question: Any opinions on whether it is or will be deprecated?

The more recent change to regcache.c:read_register_gen() should make 
this hook redundant so I'd consider it on the way out.  I'll add 
deprecating it to the TODO file.

	Andrew