bug#39248: format-time-string ignores user's preferred locale

[Paul W. Rankin]

On Thu, Jan 23 2020, Eli Zaretskii wrote:
>
> What is your value of system-time-locale?

system-time-locale -> nil

So, this works:

    (setq system-time-locale (getenv "LANG"))
    (format-time-string "%x")
    -> "23/01/2020"

But in the Elisp manual:

 -- Variable: system-time-locale
     This variable specifies the locale to use for formatting time
     values.  Changing the locale can cause messages to appear according
     to the conventions of a different language.  If the variable is
     ‘nil’, the locale is specified by environment variables in the
     usual POSIX fashion.

So the issue appears to be instead that ^this doesn't seem to be
happening...