bug#9655: 24.0.50; `set-locale-environment' should use completion

[Eli Zaretskii]

> From: Lars Ingebrigtsen <larsi@gnus.org>
> Cc: drew.adams@oracle.com,  9655@debbugs.gnu.org
> Date: Wed, 25 Aug 2021 14:36:19 +0200
> 
> >   (mapcar 'w32-get-locale-info (w32-get-valid-locale-ids))
> 
> Looking at `set-locale-environment', it already has a bunch of hacks
> that depend on Unix-related stuff:
> 
>   (setq locale-translation-file-name
>       (let ((files
>              '("/usr/share/X11/locale/locale.alias" ; e.g. X11R7
> 
> I wonder whether we should just add an equally hacky `get-locale-names'
> function that would call that w32 function (if defined), and if not,
> just parse the output of "locale -a" (if "locale" exists on the system).
> 
> Any opinions?

Before invoking 'locale -a', wouldn't it be better to use
locale-translation-file-name?

Otherwise sounds like a plan ;-)