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

["Lennart Borgman (gmail)" <lennart.borgman@gmail.com>]

Eli Zaretskii wrote:
>> Date: Thu, 07 Aug 2008 20:51:11 +0200
>> From: "Lennart Borgman (gmail)" <lennart.borgman@gmail.com>
>> CC: Ted Zlatanov <tzz@lifelogs.com>, bug-gnu-emacs@gnu.org
>>
>> Eli Zaretskii wrote:
>>>> From: Ted Zlatanov <tzz@lifelogs.com>
>>>> Date: Thu, 07 Aug 2008 08:20:46 -0500
>>>>
>>>> We could build a database of known Microsoft timezones and map them to
>>>> ISO timezones.  It has to be done just once and then updated very
>>>> rarely--timezone names don't change often.  The full list of timezones
>>>> is in 
>>>>
>>>> HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Time Zones 
>>> I already mentioned this possibility in an earlier message here.  The
>>> problem is that what you actually see in `tzname' could be a localized
>>> name, not the US English name.  So unless someone finds (or crafts) an
>>> exhaustive list of all TZ names both in English and in any localized
>>> language to which each one could be translated by Windows, this will
>>> work only on some machines.
>>
>> How many time zones are there?
> 
> I see 87 on my machine.

Does that mean that there is a mapping one to many from the numeric 
format to the string format? How is that resolved?