gcc 3.4 - gnatmake has wrong gcc name

[Arnaud Charlet]

> Configure names with dots in them need to work.  Sometimes minor OS
> revisions can contain significant changes.  We can't just tell people
> that they can't use dots in configure names anymore if they want to use
> Ada.

They work, since you can always call cross-gcc independently, and also
call gnatmake --GCC= to work around this limitation, this we're only talking
about a (desirable) improvement. That's why I'd rather get it right rather
than half baked.

> Perhaps we should try a different tack here.  Find the "gnatmake" in the
> program name and drop everything after that.  This assumes gnatmake will
> never be renamed, but that doesn't seem like much of a risk.

Possibly, although this wouldn't work with --program-suffix.
We don't support it for Ada anyway (see PR ada/864), but it would be nice
to take it into account as well if possible.

Arno