PATCH: mkfixinc.sh fixes

[Joe Buck]

> > It matches blah-blah-linux-gnu. So we have to apply my fix or to remove
> > that triplet from the list. IMHO the later, because *-*-gnu* is way too
> > general - something more specific should be put there instead.
> 
> Yep.  General questions:
> 
> 1.  Which set of platforms does not match *-*-linux* but does match
>     *-*-gnu*?

The Hurd.

> 2.  Should they be using the fixincludes, too?  (i.e., Should we clobber
>     the "*-*-gnu*" exception as well as the linux one?)

I suspect that at least for Debian GNU/Hurd they are using much the same
headers as for Debian GNU/Linux, so whatever is true for one is true of
the other.

But then, I don't know ... any Hurd hackers on this list?