[tz] Merged 1970+ time zones should always return -1 pre-1970

[Paul Eggert]

On 9/28/21 13:27, Michael H Deckers wrote:
>     When you merged Africa/Bamako with Africa/Abidjan (in 2014f), you also
>     eradicated for the people of Mali their date of independence from France

Nothing was "eradicated". All that information is still in tzdb.

Also, the 'backzone' line you're referring to ("-1:00 - -01 1960 Jun 20" 
[1]) is surely wrong, and so doesn't belong in a high-quality 
timekeeping database regardless of when Mali became independent.

The more we get bogged down with irrelevant 'backzone' trivia like the 
date of Mali's independence, the less time we'll have to make genuinely 
useful improvements to tzdb, such as some of the improvements recently 
discussed on this list. Let's focus on these improvements rather than 
rehashing past mistakes.

[1] 
https://github.com/eggert/tz/blob/6c15079a0fa34a879639e0f9baab92a472ef63a0/backzone#L182