[tz] Some rules in tz specification files seem to be applied (by zic) outside of their declared period of applicability

[Guy Harris]

On Jan 15, 2019, at 12:48 PM, Parsifal Herzog <parsifal.herzog at parz.ca> wrote:

> # RULE    NAME    FROM    TO    TYPE    IN    ON    AT    SAVE LETTER/S
> 
> # Vanguard section, for zic and other parsers that support negative DST.
> Rule    Namibia    1994    only    -    Mar    21    0:00 -1:00 WAT
> Rule    Namibia    1994    2017    -    Sep    Sun>=1    2:00 0    CAT
> Rule    Namibia    1995    2017    -    Apr    Sun>=1    2:00 -1:00    WAT

Namibia gained independence on 1990-03-21; what were the statutory time zone and DST rules from 1990-03-21 through 1994-03-20?