zoneinfo-right; leap seconds

[Olson, Arthur David]

I've incorporated Guy Harris' asctime_r and ctime_r changes, Paul
Eggert's data changes, and Paul's Makefile change to
create zoneinfo-right and zoneinfo-posix rather than zoneinfo/right and
zoneinfo/posix. Before making new tz...gz stuff available, though, a
question: might a name more neutral than "zoneinfo-right" be better?
(I'm mindful of our past experience with "Pacific-New"; I don't want to
unnecessarily tempt folks to replace "zoneinfo" with "zoneinfo-right".)

On leap seconds: having a single leap second file would eliminate the
ability to have "rolling" leap seconds. (This was provided when, one
year, the city of New York announced that the countdown for the dropping
of the big ball that marks the beginning of the new year would run
"3...2...1...LEAP...Happy New Year!", putting the leap second at
midnight local time. The time zone data as distributed reflects
internationally agreed
leap-second-occurs-at-the-same-instant-everywhere-on-Earth behavior.)

				--ado