RFC: Warn at quit that we will kill the program

[Joel Brobecker]

> Sandra noticed that GDB's exit message does not say we're about to
> kill the running program.  In native debugging this is somewhat
> apparent (though not completely), but not in remote debugging.
> 
> What do you think of this patch?

No problem on my end. I like the fact that we're more precise with
little effort, and that the message is now consistent with the case
when we attached to the process rather than starting it.

-- 
Joel