[tz] [PROPOSED] Merge timezones that are alike since 1970

[Paul Eggert]

On 5/29/21 1:09 PM, John Hawkinson wrote:
> There is a big difference between (1) "MERGING zones across modern countries" and (2) allowing to persist "zones [that] have crossed national boundaries for decades."

It's a big difference only to those closely following the history of 
tzdb. It's not a big difference to users.

The current patch was not prompted by purism. It was prompted by a 
complaint from a user who made a good point about the politics of tzdb 
2021a, which can reasonably be interpreted to favor countries like 
Norway etc. over countries like Kosovo etc. Rejecting this kind of 
complaint and saying "we've always done it that way" is not a promising 
path forward.

tzdb has had zones crossing international borders for decades, and it's 
been fine. We moved politically-motivated links to 'backward' starting 
eight years ago, and that worked fine. We moved politically-motivated 
zones to 'backzone' starting seven years ago and tzdb has rolled along 
just fine since then too. This is one patch in a long line, and as far 
as I can see it'll work out fine too.