zoneinfo: updated to 2026c release

[Wedmer]

📦 Package Details

Maintainer: me

Description:

Briefly:

 Alberta moved to permanent -06 on 2026-06-18.
 Morocco moves to permanent +00 on 2026-09-20.
 More integer overflow bugs have been fixed in zic.

Changes to future timestamps

 Alberta’s 2026-03-08 spring forward was its last foreseeable clock
 change, as it moved to permanent -06 thereafter.  (Thanks to Roozbeh
 Pournader and others.)  Model this with its traditional abbreviation
 CST.  Although the change to permanent -06 legally took place on
 2026-06-18, temporarily model the change to occur on 2026-11-01 at
 02:00 instead, for the same reason we introduced a similarly
 temporary hack for British Columbia in 2026b.

   Although another TZDB release will likely be needed soon because
   Northwest Territories will likely follow Alberta, the legal
   formalities have not yet taken place.

 Morocco plans to move back to permanent UTC, without daylight
 saving time transitions, on 2026-09-20 at 02:00.  This also
 affects Western Sahara.

Changes to code

 zic no longer overflows integers when processing outlandish input
 like ‘Zone Ouch 0 - LMT 9223372036854775807’, ‘Zone Ouch 0
 2562047788015215 LMT’, ‘Zone Ouch -2562047788015215:30:08 - LMT’,
 and ‘Zone Ouch -2562047788015215:30:08 - %%z’.  This avoids
 undefined behavior in C.  (Problems reported by Naveed Khan.)

 On platforms that have EFTYPE, tzalloc now fails with errno set to
 EFTYPE, not EINVAL, if it detects that the TZif file has an
 invalid format or is not a regular file.  Formerly it did this
 only on NetBSD, and only when the file was not a regular file.

 Unprivileged programs no longer require TZif files to be regular
 files or reject relative names containing ".." components.  This
 reverts to the more-permissive 2025b behavior, as the stricter
 behavior did not catch on in FreeBSD.

 zic now reports any failure to remove a temporary file when
 cleaning up after a previous failure.  (Problem reported by Tom
 Lane.)

Changes to commentary

 Northwest Territories is expected to move to permanent -06 prior to
 2026-11-01 02:00, when clocks would otherwise fall back.  (Thanks to
 Tim Parenti and James Bellaire.)  Model this with its traditional
 abbreviation CST.  Unfortunately the change is not yet official, so
 it is currently present only as comments that can be uncommented as
 needed.

Changes to build procedure

 The undocumented ‘typecheck’ Makefile check rule has been removed.
 It stopped working in 2025a and evidently nobody noticed.
 The rule was superseded by ‘check_time_t_alternatives’ in 2013d.

---

🧪 Run Testing Details

• OpenWrt Version: OpenWRT master
• OpenWrt Target/Subtarget: TI OMAP3/4/AM33xx, default
• OpenWrt Device:

---

✅ Formalities

• I have reviewed the CONTRIBUTING.md file for detailed contributing guidelines.