[tz] suggestion: split "backward" into "backward" and "deprecated"

[Tom Lane]

Andrew Gierth <andrew at tao11.riddles.org.uk> writes:
> But the real point here is that we _want_ some of the backward zones -
> especially the ones that users may have legitimately configured with
> tzsetup (which reads zone.tab / zone1970.tab) in the past but which got
> renamed (as in the recent example of America/Godthab).
> The problem right now is that there isn't a way to conveniently
> distinguish those zones from the ones that just get in the way and cause
> confusion. This is why my proposal retains in the "backward" file every
> zone that has ever been in zone.tab.

It's not clear to me whether your proposal includes removal of the
newly "deprecated" zones from the default build rule.  If it doesn't,
then this is just paper-shuffling so far as many (most?) consumers of
tzdata are concerned.  It gets considerably more real if the proposal
is to not include the "deprecated" source file in the standard Makefile
build rule.

Postgres, for instance, has for some time just used whatever is in the
distributed tzdata.zi file.  So we'd either continue to support these
zones, or not, depending on what happens in the build process for that
file.

I don't currently have an opinion on whether changing that would be
a good or bad thing ... but as far as I could see, you didn't say what
you wanted to happen.

			regards, tom lane