[PATCH] Remove a copy from c-exp.y:parse_number

[Tom Tromey]

Keith> I committed that over a decade ago, and my notes mention some
Keith> of the difficulties with generic parser constification I was
Keith> having at the time, including having to fudge several places
Keith> with alloca.

Keith> So if there was a reason for it back then, it was a hack, and
Keith> it is now obviously long gone.

I vaguely recall that this area went through constification in stages
and so we had to introduce copies in some spots.

Keith> Reviewed-by: Keith Seitz <keiths@redhat.com>

I'm going to check it in now.

Tom