bug#641: format-time-string %Z does not work, starting with Emacs 22.2

[Eli Zaretskii <eliz@gnu.org>]

> Date: Thu, 07 Aug 2008 23:20:22 +0200
> From: martin rudalics <rudalics@gmx.at>
> CC: "Lennart Borgman (gmail)" <lennart.borgman@gmail.com>, 
>  tzz@lifelogs.com,  bug-gnu-emacs@gnu.org
> 
>  >>How many time zones are there?
>  >
>  > I see 87 on my machine.
> 
> Hmmm ... I suppose these include DSTs.

No, they are just _names_.  Under each name there are rules for
switching between standard and daylight-saving time, and also the
specific strings to use as the time-zone name during standard and
daylight-saving periods.

> Anyway, wouldn't we have to multiply this with the number of
> languages supported?

Each name should be multiplied by the number of spellings in different
languages supported by the corresponding locale.  I don't know what is
the multiplication factor, but it's probably at least 2.  And that's
in addition to the 2 values for standard and daylight-saving periods.

However, the sheer number of the possible names is not the issue now.
It's the fact that we simply do not know all the possible spellings
that makes this idea impossible to implement at this time.