tzdata: Update to version 2023c-1

tzdata: Update to version 2023c-1

- IPFire-3.x
- Update from verrsion 2022g-2 to 2023c-1
- Changelog
    2023c
	This release's code and data are identical to 2023a.  In other words,
	 this release reverts all changes made in 2023b other than commentary, as
	 that appears to be the best of a bad set of short-notice choices for
	 modeling this week's daylight saving chaos in Lebanon. (Thanks to Rany
	 Hany for the heads-up about the government's announcement this week.)
    2023b
	The 2023b release of the tz code and data is available. It follows so
	 closely on the 2023a release because Lebanon's government announced that
	 Lebanon's spring-forward transition previously scheduled for the end of
	 this week has been delayed until April 20.
	This release contains the following change:
	   Briefly:
	     Lebanon delays the start of DST this year.
	   Changes to future timestamps
	     This year Lebanon springs forward April 20/21 not March 25/26.
	     (Thanks to Saadallah Itani.)
    2023a
	   Briefly:
	     Egypt now uses DST again, from April through October.
	     This year Morocco springs forward April 23, not April 30.
	     Palestine delays the start of DST this year.
	     Much of Greenland still uses DST from 2024 on.
	     America/Yellowknife now links to America/Edmonton.
	     tzselect can now use current time to help infer timezone.
	     The code now defaults to C99 or later.
	     Fix use of C23 attributes.
	   Changes to future timestamps
	     Starting in 2023, Egypt will observe DST from April's last Friday
	      through October's last Thursday.  (Thanks to Ahmad ElDardiry.)
	      Assume the transition times are 00:00 and 24:00, respectively.
	     In 2023 Morocco's spring-forward transition after Ramadan
	      will occur April 23, not April 30.  (Thanks to Milamber.)
	      Adjust predictions for future years accordingly.  This affects
	      predictions for 2023, 2031, 2038, and later years.
	     This year Palestine will delay its spring forward from
	      March 25 to April 29 due to Ramadan.  (Thanks to Heba Hamad.)
	      Make guesses for future Ramadans too.
	     Much of Greenland, represented by America/Nuuk, will continue to
	      observe DST using European Union rules.  When combined with
	      Greenland's decision not to change the clocks in fall 2023,
	      America/Nuuk therefore changes from -03/-02 to -02/-01 effective
	      2023-10-29 at 01:00 UTC.  (Thanks to Thomas M. Steenholdt.)
	      This change from 2022g doesn't affect timestamps until 2024-03-30,
	      and doesn't affect tm_isdst until 2023-03-25.
	   Changes to past timestamps
	     America/Yellowknife has changed from a Zone to a backward
	      compatibility Link, as it no longer differs from America/Edmonton
	      since 1970.  (Thanks to Almaz Mingaleev.)  This affects some
	      pre-1948 timestamps.  The old data are now in 'backzone'.
	   Changes to past time zone abbreviations
	     When observing Moscow time, Europe/Kirov and Europe/Volgograd now
	      use the abbreviations MSK/MSD instead of numeric abbreviations,
	      for consistency with other timezones observing Moscow time.
	   Changes to code
	     You can now tell tzselect local time, to simplify later choices.
	      Select the 'time' option in its first prompt.
	     You can now compile with -DTZNAME_MAXIMUM=N to limit time zone
	      abbreviations to N bytes (default 255).  The reference runtime
	      library now rejects POSIX-style TZ strings that contain longer
	      abbreviations, treating them as UTC.  Previously the limit was
	      platform dependent and abbreviations were silently truncated to
	      16 bytes even when the limit was greater than 16.
	     The code by default is now designed for C99 or later.  To build in
	      a C89 environment, compile with -DPORT_TO_C89.  To support C89
	      callers of the tzcode library, compile with -DSUPPORT_C89.  The
	      two new macros are transitional aids planned to be removed in a
	      future version, when C99 or later will be required.
	     The code now builds again on pre-C99 platforms, if you compile
	      with -DPORT_TO_C89.  This fixes a bug introduced in 2022f.
	     On C23-compatible platforms tzcode no longer uses syntax like
	      'static [[noreturn]] void usage(void);'.  Instead, it uses
	      '[[noreturn]] static void usage(void);' as strict C23 requires.
	      (Problem reported by Houge Langley.)
	     The code's functions now constrain their arguments with the C
	      'restrict' keyword consistently with their documentation.
	      This may allow future optimizations.
	     zdump again builds standalone with ckdadd and without setenv,
	      fixing a bug introduced in 2022g.  (Problem reported by panic.)
	     leapseconds.awk can now process a leap seconds file that never
	      expires; this might be useful if leap seconds are discontinued.
	   Changes to commentary
	     tz-link.html has a new section "Coordinating with governments and
	      distributors".  (Thanks to Neil Fuller for some of the text.)
	     To improve tzselect diagnostics, zone1970.tab's comments column is
	      now limited to countries that have multiple timezones.
	     Note that leap seconds are planned to be discontinued by 2035.

Signed-off-by: Adolf Belka <adolf.belka@ipfire.org>
Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>