bug#36649: 27.0.50; pure space and pdumper

[Eli Zaretskii]

> From: Lars Ingebrigtsen <larsi@gnus.org>
> Cc: monnier@iro.umontreal.ca,  pipcet@gmail.com,  eggert@cs.ucla.edu,
>   rpluim@gmail.com,  schwab@linux-m68k.org,  stefan@marxist.se,
>   36649@debbugs.gnu.org,  akrl@sdf.org
> Date: Wed, 12 May 2021 19:32:13 +0200
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> > Keeping unexec doesn't mean breaking it .  If we believe someone might
> > need that configuration, then we should give them a full-fledged
> > Emacs, not a crippled one.
> 
> How crippled are we talking?

As in "less efficient".

> > The patch can easily be tweaked to make the changes conditioned by
> > HAVE_PDUMPER, so I believe there's no need to argue about this nit:
> > let's simply remove purespace from the pdumper builds, and leave it
> > alone in the unexec builds.
> 
> That would be a whole lot of #ifs in the code, and wouldn't make the
> change worth it -- in that case, I'd rather wait until we get rid of 
> unexec before getting rid of pure space.

I don't think it will be so ugly as being prohibitive: we already have
quite a few of "#if HAVE_PDUMPER" in the sources.  But if you prefer
to wait with purespace removal until after unexec is removed, I don't
mind too much: Emacs 28 will have quite a lot of important changes
even without that.