Re: 23.0.50; on Windows, M-x display-time-world shows the same, incorrect, time for all cities

[Eli Zaretskii <eliz@gnu.org>]

> Date: Sat, 27 Oct 2007 15:09:11 +0100
> From: Jason Rumney <jasonr@gnu.org>
> Cc: offby1@blarg.net, emacs-pretest-bug@gnu.org, apple@kanis.eu
> 
> BST0BDT should be GMT0BST
> JST-9JDT should be JST-9 (no daylight savings in Japan).
> I think there may also be no daylight savings in India, but I'm not sure.

Thanks, I fixed these (you were right about India).

> Also, I think enabling the zoneinfo style names only on GNU/Linux and MS
> DOS is too conservative.

I simply don't know exactly which ones support zoneinfo, and don't
have access to any other system besides those two.  The tzcode package
says that HP, Solaris, and SGI also support it, but don't provide the
details, and at least SGI Irix 6.5 didn't support zoneinfo back when I
worked on it 3 years ago, so the support could be version-specific.

Please feel free to modify the list as appropriate...

> It may be better to use those by
> default, and enable the legacy ones on a case by case basis,

...or make this change, if it's deemed better.

It strikes me that the best would be to test the support at run time,
and do TRT accordingly.  If someone knows how to test this, maybe such
a test should be part of `set-time-zone-rule', and then
`display-time-world' could use it.