Spurious ALLEGRO failure

[Robert Goldman]

I'm getting what look like spurious failures on tests of "allegro" in
test-program.script.

I *believe* that what's going wrong here is that lisp-invocation is
getting confused about how to find the right ACL runtime.

If you look at run-tests.sh, you will see that "ALLEGRO" is initially
bound using the funky logic at the top of the file, but then is REBOUND
on windows to use buildi instead of alisp on that platform....

I *suspect* this is breaking things, because I suspect that the logic
for reasoning about the ALLEGRO installation directories is getting run
more than once, causing INVOKE-LISP to fail.  But INVOKE-LISP doesn't
provide any useful information about how it's invoking lisp.

I'll investigate somewhat further, but if an explanation jumps out at
you, please LMK.

I believe that this conjecture is supported by the fact that it is only
the "allegro" tests that fail -- not allegro64, none of the modern
variants, etc.

Cheers,
r