bug#28597: 26.0.60; [Security] Configure should use --without-pop by default

[Eli Zaretskii]

> From: John Wiegley <jwiegley@gmail.com>
> Date: Tue, 26 Sep 2017 11:51:59 -0700
> Cc: "N. Jackson" <nljlistbox2@gmail.com>, 28597@debbugs.gnu.org
> 
> >>>>> Paul Eggert <eggert@cs.ucla.edu> writes:
> 
> > As Glenn noted, the 'configure' message N. mentions came from an uneasy
> > compromise between worry about the default lack-of-security in Emacs, and
> > worry about backward compatibility (see Bug#26102). Although I favor making
> > --without-pop the default, at this point it's really an issue for the two
> > maintainers to decide.
> 
> I'm OK making it the default. Let's wait until Eli's back from his trip and he
> can add his thoughts.

I already agreed in
http://lists.gnu.org/archive/html/emacs-devel/2017-08/msg00054.html to
have --without-pop be the default, and Paul already installed a patch
to do that.  So I'm confused about this discussion: what exactly is
the problem, and what needs to be done/decided?  Are we talking about
Posix systems where GNU Mailutils are not available?  If so, do we
want to leave them without movemail at all rather than with one which
supports POP3?  Or do we want to give them movemail, but without POP3?

IOW, from my POV, most of the issues addressed in the cited bug#26102
were resolved as proposed there many moons ago, and I'm unsure what's
left, and why is it a problem.