bug#57129: 29.0.50; Improve behavior of conditionals in Eshell

[Eli Zaretskii <eliz@gnu.org>]

> Date: Tue, 16 Aug 2022 10:25:57 -0700
> Cc: bug-gnulib@gnu.org, larsi@gnus.org, 57129@debbugs.gnu.org,
>  jporterbugs@gmail.com
> From: Paul Eggert <eggert@cs.ucla.edu>
> 
> On 8/16/22 09:25, Eli Zaretskii wrote:
> > why does this work differently on
> > different platforms?
> 
> Platforms that lack clock_gettime and CLOCK_MONOTONIC fall back on a 
> deterministic algorithm. Presumably MS-DOS one of the few such 
> platforms, which is why the problem is observed only on MS-DOS.

(Why are you talking about MS-DOS?)

MinGW does have clock_gettime, but we don't want to use it, because
one of the MinGW flavors (MinGW64) implements that function in
libwinpthreads, and that makes Emacs depend on libwinpthreads DLL,
which we want to avoid.

> How about something like the attached patch to Gnulib's lib/tempname.c? 

Thanks, but why not use 'random' instead?  Emacs does have it on all
platforms, including MS-Windows.  AFAIU, it's better than 'rand'.

> If I understand things correctly this should make the names random 
> enough on MS-DOS, though Emacs itself still needs a patch as I mentioned 
> a few minutes ago.

Why would Emacs need that patch?