[tz] RFC 8536bis

[Michael H Deckers]

    In 2014b, the new tzdb timezone for Antarctica/Troll required
    regular switches among three offsets for the foreseeable future.
    This led to an extension of the TZif format so that the footer
    could contain two TZ strings (or so I thought); the timezone
    Antarctica/Troll, hwever, was modified so as to not yet require
    the new TZif feature.

    Now it appears that the latest specification "RFC 8536bis" of the
    TZif format does not allow for two TZ strings in the footer (or
    at least I did not detect it).

    Does that mean that the feature "two TZ strings" in a TZif
    file is further postponed, or is it dropped for good?

    Michael Deckers.