[tz] New IANA-timezone support date/time library

[Paul Gilmartin]

On 2021-02-22, at 11:04:48, Brian Park via tz wrote:
> 
> Thanks for the info. I scanned through the Readme page, but I couldn't find the answer to my question: Does your library have the ability to set the underlying database to a specific TZDB version (e.g. 2019f, 2021a)?
>  
How many TZDB versions do you want to support?

> I would like this feature to get deterministic functional testing, instead of having the OS change the underlying TZDB version underneath me. The HowardHinnant C++ date library (https://github.com/HowardHinnant/date) is the only library that I know that has this feature. I am looking for a second library.
>  
I notice that on MacOS or Linx I can use parent directory (TZ=../.. etc.)
references and/or symbolic links to access a customized version of TZDB
Does that help you?

-- gil