darcs patch: Figure out timezone offset from timezone name

[Ashley Yakeley]

On Tue, 2008-02-05 at 09:23 +0100, David Leuschner wrote:
> >> Which time zone is used at what time indeed changes frequently but I am
> >> not aware of any case where the meaning of a time zone _name_ changed.
> >
> > What's your source for time-zone names?
> 
> I just realised I forgot to add a comment in the patch.  It's the table
> from the PostgreSQL manual
> 
> http://www.postgresql.org/docs/8.1/static/datetime-keywords.html

OK, we should certainly include a link in the source. But why this
particular set? Where did PostgreSQL get them from?

I Googled and found this:
http://www.worldtimezone.com/wtz-names/timezonenames.html
http://www.worldtimezone.com/wtz-names/wtz-vet.html 

Venezuela Time certainly has changed offset. The question is, is "VET"
somehow less standard as an abbreviation than the ones in the PostgreSQL
list? Alternatively, are the ones listed less liable to change?

-- 
Ashley Yakeley