bug#45817: 28.0.50; Native fails

[Eli Zaretskii]

> From: Andrea Corallo <akrl@sdf.org>
> Cc: "Kirill A. Korinsky" <kirill@korins.ky>, 45817@debbugs.gnu.org
> Date: Thu, 14 Jan 2021 09:33:48 +0000
> 
> > Is this specific to macOS?
> >
> > In any case, if it's known that specific versions of GCC cause
> > problems on specific platforms, we should reject those versions (for
> > the libgccjit usage purposes) in configure, I think.
> 
> We do, not based on the version but (even better I think) we run a
> functional test at configure time.  The test use libgccjit to produce a
> shared, then this is loaded and used to ensure all the complete
> mechanism is functional.

Yes, but such tests can only verify that the basics work, whereas the
OP seemed to indicate that it generally works, but fails in some
subtle situation.  If libgccjit you are testing at configure time only
"mostly" works, you will be unable to detect that with simple tests.
For such subtly broken versions of libgccjit, we have no practical
means but looking at their version.

> I think in this specific case somenthing happend (maybe OS upgrade?) as
> when Emacs was compiled libgccjit clearly was working.

If that is the case, then there's no problem we need to solve here.