[tz] tzfiles contain Unix epoch for the first transition time

[Paul Eggert]

Paul Eggert wrote:
> The second, at file offset 1356, is for -2717650800 (0xffffffff5e03f090), which
> is 1883-11-18 17:00:00 UTC.

Sorry, I misinterpreted that one.  The second one is actually for -2717647200 
(0xffffffff5e03fea0), which is 1883-11-18 18:00:00 UTC, and this agrees with 
your program.  So the problem is only with the first transition; the second one 
looks OK.