[RFA 5/6] Change Ada exceptions to use std::string

[Joel Brobecker]

> Joel> Pb #1: Crash while trying to insert an assert catchpoint:
> 
> I wonder why I didn't see any problems from the buildbot.
> 
> Joel> Pb #3: condition handling in exception catchpoints is broken
> 
> Joel>     Tom removed a call to "skip_spaces" before checking for the next
> Joel>     argument, and I am not sure I understand why.
> 
> Here I was confused and thought extract_arg skipped spaces again after
> extracting the arg.  But, it doesn't.
> 
> Still - why not test failures?  This is disturbing.

That's indeed strange. Do we have access to the reference report?
Maybe the Ada testing is not run (eg: missing Ada compiler on
the buildbot), or maybe the Ada compiler there is such that the tests
were failing in the first place, preventing it from detecting
regressions?

In any case, I'm quite happy to be the safety net in this case...

-- 
Joel