bug#36649: 27.0.50; pure space and pdumper

[Eli Zaretskii]

> From: Lars Ingebrigtsen <larsi@gnus.org>
> Cc: eggert@cs.ucla.edu,  rpluim@gmail.com,  stefan@marxist.se,
>   schwab@linux-m68k.org,  monnier@iro.umontreal.ca,  pipcet@gmail.com,
>   36649@debbugs.gnu.org,  akrl@sdf.org
> Date: Wed, 12 May 2021 20:48:28 +0200
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> > Someone built the master branch with unexec just a few days ago, see
> >
> >   https://lists.gnu.org/archive/html/emacs-devel/2021-05/msg00060.html
> 
> That's on Windows, though, and I seem to recall you fixing unexec on
> Windows a couple weeks ago?

I worked with him to fix it, yes.  But the problem and the fix were
not Windows specific, AFAIR.  I guess there's more, and perhaps it
happens only on systems which don't use mmap for buffer text.  I will
try to take a look when I have time.