bug#46916: 28.0.50; pure_alloc(10424, ...) fails badly when pure space is exhausted

[Eli Zaretskii]

> From: Stefan Kangas <stefan@marxist.se>
> Date: Sun, 31 Oct 2021 07:02:47 -0700
> Cc: Eli Zaretskii <eliz@gnu.org>, 46916@debbugs.gnu.org
> 
> Eli, I'm not sure if your previous reply was just intended to say "we
> normally just increase the size of purespace", or if you also object to
> installing this patch?

I don't see a need for anything more complex than enlarging the pure
space, yes.  in fact, I don't even see a reason to enlarge the pure
space, since no one else reported a problem with the existing amount
of pure space.