Version 2022.6

Upstream version 2022f released 2022-10-29T01:04:57+00:00

Briefly:

Mexico will no longer observe DST except near the US border. Chihuahua moves to
year-round -06 on 2022-10-30. Fiji no longer observes DST. Move links to
'backward'. In vanguard form, GMT is now a Zone and Etc/GMT a link. zic now
supports links to links, and vanguard form uses this. Simplify four Ontario
zones. Fix a Y2438 bug when reading TZif data. Enable 64-bit time_t on 32-bit
glibc platforms. Omit large-file support when no longer needed. In C code, use
some C23 features if available. Remove no-longer-needed workaround for Qt bug
53071.

Changes to future timestamps.

Mexico will no longer observe DST after 2022, except for areas near the US
border that continue to observe US DST rules. On 2022-10-30 at 02:00 the Mexican
state of Chihuahua moves from -07 (-06 with DST) to year-round -06, thus not
changing its clocks that day. The new law states that Chihuahua near the US
border no longer observes US DST.

Fiji will not observe DST in 2022/3. (Thanks to Shalvin Narayan.) For now,
assume DST is suspended indefinitely.

Changes to data

Move links to 'backward' to ease and simplify link maintenance. This affects
generated data only if you use 'make BACKWARD='.

GMT is now a Zone and Etc/GMT a link instead of vice versa, as GMT is needed for
leap second support whereas Etc/GMT is not. However, this change exposes a bug
in TZUpdater 2.3.2 so it is present only in vanguard form for now.

Vanguard form now uses links to links, as zic now supports this.

Changes to past timestamps

Simplify four Ontario zones, as most of the post-1970 differences seem to have
been imaginary. (Problem reported by Chris Walton.) Move America/Nipigon,
America/Rainy_River, and America/Thunder_Bay to 'backzone'; backward-
compatibility links still work, albeit with some different timestamps before
November 2005.