bug#56743: 29.0.50; Sharing .eln files beween different builds

[Eli Zaretskii <eliz@gnu.org>]

> From: Stefan Monnier <monnier@iro.umontreal.ca>
> Cc: 56743@debbugs.gnu.org
> Date: Sun, 24 Jul 2022 13:49:42 -0400
> 
> >> It would be good to try and make sure the `.eln` files can be shared
> >> between different builds of the release tarballs (ie. the exact same
> >> source code, just configured differently).  This would be beneficial for
> >> example for distributions like Debian which offer `emacs-nox`,
> >> `emacs-gtk`, and emacs-lucid` variants, which could then share the
> >> `.eln` files.
> >
> > You want to remove the dependence of .eln files on the primitives that
> > are implemented in C?
> 
> No, just make sure the hash used to find the `.eln` doesn't depend
> whether the build is made with Lucid or Gtk or something else.

AFAIU, if the set of the primitives is identical in the builds, the
*.eln files should be compatible.  But I think there are primitives in
some of these builds that don't exist in others; thus my question.

> IIUC this mostly means that all the Gtk/Lucid/X11-specific
> functions&variables exported to ELisp will need to be exported in all
> the builds (probably with dummy definitions).

Even if this makes sense (and I'm not sure it does), this is a lot of
work for very little gain.