RFC: dummy.[hc] and ``struct dummy''

[Andrew Cagney]

Hello,

I'd like to float the idea of moving all the generic dummy frame code 
into a new file dummy.[hc].

Things like hand_function_call() would then use a ``struct dummy'' that 
contains the information for the dummy frame currently being 
constructed.  That way the current global top-of-dummy stack assumption 
is removed.

This should also make it simplier/easier to do things like make what is 
currently a single global dummy frame stack part of the ``thread_info'' 
object.  (Figuring out why one would want to do this is left as an 
exercise for the reader.  LiamS, GraceS and I stumbled across this 
think-o :-).

Andrew