Updated: tzcode, tzdata 2023d

[Cygwin tzcode/tzdata Maintainer]

The following packages have been upgraded in the Cygwin distribution:

* tzcode	2023d
* tzdata	2023d

The Time Zone Database (often called tz, tzdb, or zoneinfo) contains
data that represents the history of local time for many locations around
the world, and supports conversion of UTC time to local time at those
locations to allow display of those local times. It is updated
periodically to reflect changes made by political bodies to summer
daylight saving time rules, UTC offsets, and time zone boundaries.
The tzcode package provides the tzselect, zdump, and zic utilities.

For more information, see the project home page:

	https://www.iana.org/time-zones

For more details on changes, see the announcement or below:

	https://mm.icann.org/pipermail/tz-announce/2023-December/000080.html


Release 2023d	2023-12-21

Briefly:

    Ittoqqortoormiit, Greenland changes time zones on 2024-03-31.
    Vostok, Antarctica changed time zones on 2023-12-18.
    Casey, Antarctica changed time zones five times since 2020.
    Code and data fixes for Palestine timestamps starting in 2072.
    A new data file zonenow.tab for timestamps starting now.

Changes to future timestamps

    Ittoqqortoormiit, Greenland (America/Scoresbysund) joins most of
    the rest of Greenland's timekeeping practice on 2024-03-31, by
    changing its time zone from -01/+00 to -02/-01 at the same moment
    as the spring-forward transition. Its clocks will therefore not
    spring forward as previously scheduled. The time zone change
    reverts to its common practice before 1981.

    Fix predictions for DST transitions in Palestine in 2072-2075,
    correcting a typo introduced in 2023a.

Changes to past and future timestamps

    Vostok, Antarctica changed to +05 on 2023-12-18. It had been at
    +07 (not +06) for years.

    Change data for Casey, Antarctica to agree with timeanddate.com,
    by adding five time zone changes since 2020. Casey is now at +08
    instead of +11.

Changes to past tm_isdst flags

    Much of Greenland, represented by America/Nuuk, changed its
    standard time from -03 to -02 on 2023-03-25, not on 2023-10-28.
    This does not affect UTC offsets, only the tm_isdst flag.

New data file

    A new data file zonenow.tab helps configure applications that use
    timestamps dated from now on. This simplifies configuration,
    since users choose from a smaller Zone set. The file's format is
    experimental and subject to change.

Changes to code

    localtime.c no longer mishandles TZif files that contain a single
    transition into a DST regime. Previously, it incorrectly assumed
    DST was in effect before the transition too.

    localtime.c's timeoff no longer collides with OpenBSD 7.4.

    The C code now uses _Generic only if __STDC_VERSION__ says the
    compiler is C11 or later.

    tzselect now optionally reads zonenow.tab, to simplify when
    configuring only for timestamps dated from now on.

    tzselect no longer creates temporary files.

    tzselect no longer mishandles the following:

      Spaces and most other special characters in BUGEMAIL, PACKAGE,
      TZDIR, and VERSION.

      TZ strings when using mawk 1.4.3, which mishandles regular
      expressions of the form /X{2,}/.

      ISO 6709 coordinates when using an awk that lacks the GNU
      extension of newlines in -v option-arguments.

      Non UTF-8 locales when using an iconv command that lacks the GNU
      //TRANSLIT extension.

    zic no longer mishandles data for Palestine after the year 2075.
    Previously, it incorrectly omitted post-2075 transitions that are
    predicted for just before and just after Ramadan.

    zic now works again on Linux 2.6.16 and 2.6.17 (2006).

Changes to build procedure

    The Makefile is now more compatible with POSIX:
    * It no longer defines AR, CC, CFLAGS, LDFLAGS, and SHELL.
    * It no longer uses its own 'cc' in place of CC.
    * It now uses ARFLAGS, with default specified by POSIX.
    * It does not use LFLAGS incompatibly with POSIX.
    * It uses the special .POSIX target.
    * It quotes special characters more carefully.
    * It no longer mishandles builds in an ISO 8859 locale.
    Due to the CC changes, TZDIR is now #defined in a file tzfile.h
    built by 'make', not in a $(CC) -D option. Also, TZDEFAULT is
    now treated like TZDIR as they have similar roles.

Changes to commentary

     Limitations and hazards of the optional support for obsolescent
     C89 platforms are documented better, along with a tentative
     schedule for removing this support.