[tz] Clarification on future direction of POSIXRULES and POSIX TZ specs?

[Paul Eggert]

Tom Lane wrote:
> will the behavior for transition-rule-less POSIX TZ
> specs be that it always falls back to the hard-wired TZDEFRULESTRING?

That sounds like a good way forward, yes. It conforms to POSIX, it corresponds 
to the intent of the ancient Unix System V code, and for timestamps after 2007 
it matches the current tzdb default behavior.