Squashed 'tz/' changes from cc48c2dfa..beeb53a3d

380c07cef Release 2024a
a97e920cd * localtime.c: Fix comment typography.
85a0aade5 Update a few stale links * theory.html, tz-art.html: Update stale links and normalize some punctuation and white space.
75c9e5923 Streamline tz-link a bit
619fcf091 Improve Czechoslovakia commentary
9740ab1de * tz-link.html: Prefer <code> to <samp> for code snippets.
983d3efb3 * tz-link.html: Mention posix_tz_db.
2903b9acf Document POSIX versions more carefully
23e7cfa05 Palestine springs forward a week later after Ramadan
f4c6e5f15 Update link to Palestine MTIT
b3d4dbb84 Fix NEWS typo for strftime
f295cc13b Mention zonenow.tab in “Theory”
e9f12c313 Update some tz-link links
f481c61c2 * zonenow.tab: Fix up west Kazakhstan comments.
7de0bfb9c Update ISO 3166-2:KZ codes for Kazakhstan
2cbd39c9e Asia/Ho_Chi_Minh: Correct 1955 transition
1fe97024d Add Kazakhstan PM’s decision
9a43feddc Update Kazakhstan region comments
39bfdc787 Fix typo in checknow.awk diagnostic
608c13d48 Pacify ‘make check’ for Kazakhstan changes
95a16c87f Kazakhstan unifies on UTC+5 beginning 2024-03-01.
845957071 Update Matthews & Vincent URI
16495d669 Improve recent Vietnam doc
893c20b04 Asia/Ho_Chi_Minh 1945-09 Source added
b7f926f32 More strftime doc improvements
fc7b8b61a Document strftime struct tm member usage
a707253f0 For strftime %z, use tm_gmtoff if available
b4ec32798 Draft next POSIX has tm_gmtoff, tm_zone
4238791ac Sort links by dest when shrinking vanguard
77e6d7f64 Sort zones by name when shrinking
b848dce41 Shrink lines by class
05588b6b5 Simplify zishrink.awk
1ca031c0d Shrink tzdata.zi a bit more if vanguard
400526081 "m" now abbreviates both "maximum" and "minimum"
f927f6e33 Don’t mention ftp.nist.gov
e6b568372 Miquelon 1911 transition was June 15 not May 15
56c15806e Toronto 1947/1949 switched at 02:00 not 00:00
cb72e39b7 make commit-leap-seconds.list
27b4d76d1 Automate copying of leap-seconds.list
5a43b0d7d Improve tzalloc etc. man page
95fa1a491 * NEWS: Fix America/Ciudad_Juarez summary.
321a49c95 Remove support for "min" in Rule lines
f83d3a375 Name two constants in zic.c
325e4efd1 Avoid pwd in tzselect when developing
d4c4422e5 Avoid sed in tzselect
d03bc3aee Avoid expr in tzselect
322abaa97 Reformat music section
d6a94fee0 Comics update
284ebde20 Fix localtime.c bug: America/Ciudad_Juarez in 2422

git-subtree-dir: tz
git-subtree-split: beeb53a3d8a62e7525d5e6345c5c7ca4bde26a6b

Makefile

@@ -53,7 +53,7 @@ DATAFORM=		main
 
 LOCALTIME=	Factory
 
-# The POSIXRULES macro controls interpretation of POSIX-like TZ
+# The POSIXRULES macro controls interpretation of POSIX-2017.1-like TZ
 # settings like TZ='EET-2EEST' that lack DST transition rules.
 # If POSIXRULES is '-', no template is installed; this is the default.
 # Any other value for POSIXRULES is obsolete and should not be relied on, as:
@@ -274,7 +274,7 @@ LDLIBS=
 #  -DTZ_DOMAINDIR=\"/path\" to use "/path" for gettext directory;
 #	the default is system-supplied, typically "/usr/lib/locale"
 #  -DTZDEFRULESTRING=\",date/time,date/time\" to default to the specified
-#	DST transitions for POSIX-style TZ strings lacking them,
+#	DST transitions for POSIX.1-2017-style TZ strings lacking them,
 #	in the usual case where POSIXRULES is '-'.  If not specified,
 #	TZDEFRULESTRING defaults to US rules for future DST transitions.
 #	This mishandles some past timestamps, as US DST rules have changed.
@@ -340,9 +340,10 @@ GCC_DEBUG_FLAGS = -DGCC_LINT -g3 -O3 -fno-common \
 # guess TM_GMTOFF from other macros; define NO_TM_GMTOFF to suppress this.
 # Similarly, if your system has a "zone abbreviation" field, define
 #	-DTM_ZONE=tm_zone
-# and define NO_TM_ZONE to suppress any guessing.  Although these two fields
-# not required by POSIX, a future version of POSIX is planned to require them
-# and they are widely available on GNU/Linux and BSD systems.
+# and define NO_TM_ZONE to suppress any guessing.
+# Although these two fields are not required by POSIX.1-2017,
+# POSIX 202x/D4 requires them and they are widely available
+# on GNU/Linux and BSD systems.
 #
 # The next batch of options control support for external variables
 # exported by tzcode.  In practice these variables are less useful
@@ -352,7 +353,7 @@ GCC_DEBUG_FLAGS = -DGCC_LINT -g3 -O3 -fno-common \
 # #	-DHAVE_TZNAME=0 # do not support "tzname"
 # #	-DHAVE_TZNAME=1 # support "tzname", which is defined by system library
 # #	-DHAVE_TZNAME=2 # support and define "tzname"
-# # to the "CFLAGS=" line.  "tzname" is required by POSIX 1988 and later.
+# # to the "CFLAGS=" line.  "tzname" is required by POSIX.1-1988 and later.
 # # If not defined, the code attempts to guess HAVE_TZNAME from other macros.
 # # Warning: unless time_tz is also defined, HAVE_TZNAME=1 can cause
 # # crashes when combined with some platforms' standard libraries,
@@ -362,8 +363,8 @@ GCC_DEBUG_FLAGS = -DGCC_LINT -g3 -O3 -fno-common \
 # #	-DUSG_COMPAT=0 # do not support
 # #	-DUSG_COMPAT=1 # support, and variables are defined by system library
 # #	-DUSG_COMPAT=2 # support and define variables
-# # to the "CFLAGS=" line; "timezone" and "daylight" are inspired by
-# # Unix Systems Group code and are required by POSIX 2008 (with XSI) and later.
+# # to the "CFLAGS=" line; "timezone" and "daylight" are inspired by Unix
+# # Systems Group code and are required by POSIX.1-2008 and later (with XSI).
 # # If not defined, the code attempts to guess USG_COMPAT from other macros.
 # #
 # # To support the external variable "altzone", add
@@ -427,7 +428,7 @@ GCC_DEBUG_FLAGS = -DGCC_LINT -g3 -O3 -fno-common \
 
 # The name of a POSIX-like library archiver, its flags, C compiler,
 # linker flags, and 'make' utility.  Ordinarily the defaults suffice.
-# The commented-out values are the defaults specified by POSIX 202x/D3.
+# The commented-out values are the defaults specified by POSIX.1-202x/D4.
 #AR = ar
 #ARFLAGS = -rv
 #CC = c17
@@ -439,6 +440,12 @@ GCC_DEBUG_FLAGS = -DGCC_LINT -g3 -O3 -fno-common \
 
 LEAPSECONDS=
 
+# Where to fetch leap-seconds.list from.
+leaplist_URI = \
+  https://hpiers.obspm.fr/iers/bul/bulc/ntp/leap-seconds.list
+# The file is generated by the IERS Earth Orientation Centre, in Paris.
+leaplist_TZ = Europe/Paris
+
 # The zic command and its arguments.
 
 zic=		./zic
@@ -471,7 +478,8 @@ AWK=		awk
 # is typically nicer if it works.
 KSHELL=		/bin/bash
 
-# Name of curl <https://curl.haxx.se/>, used for HTML validation.
+# Name of curl <https://curl.haxx.se/>, used for HTML validation
+# and to fetch leap-seconds.list from upstream.
 CURL=		curl
 
 # Name of GNU Privacy Guard <https://gnupg.org/>, used to sign distributions.
@@ -718,6 +726,28 @@ leapseconds:	$(LEAP_DEPS)
 		  -f leapseconds.awk leap-seconds.list >$@.out
 		mv $@.out $@
 
+# Awk script to extract a Git-style author from leap-seconds.list comments.
+EXTRACT_AUTHOR = \
+  author_line { sub(/^.[[:space:]]*/, ""); \
+      sub(/:[[:space:]]*/, " <"); \
+      printf "%s>\n", $$0; \
+      success = 1; \
+      exit \
+  } \
+  /Questions or comments to:/ { author_line = 1 } \
+  END { exit !success }
+
+# Fetch leap-seconds.list from upstream.
+fetch-leap-seconds.list:
+		$(CURL) -OR $(leaplist_URI)
+
+# Fetch leap-seconds.list from upstream and commit it to the local repository.
+commit-leap-seconds.list: fetch-leap-seconds.list
+		author=$$($(AWK) '$(EXTRACT_AUTHOR)' leap-seconds.list) && \
+		date=$$(TZ=$(leaplist_TZ) stat -c%y leap-seconds.list) && \
+		git commit --author="$$author" --date="$$date" -m'make $@' \
+		  leap-seconds.list
+
 # Arguments to pass to submakes of install_data.
 # They can be overridden by later submake arguments.
 INSTALLARGS = \
@@ -1315,7 +1345,8 @@ zic.o:		private.h tzfile.h tzdir.h version.h
 .PHONY: ALL INSTALL all
 .PHONY: check check_mild check_time_t_alternatives
 .PHONY: check_web check_zishrink
-.PHONY: clean clean_misc dummy.zd force_tzs
+.PHONY: clean clean_misc commit-leap-seconds.list dummy.zd
+.PHONY: fetch-leap-seconds.list force_tzs
 .PHONY: install install_data maintainer-clean names
 .PHONY: posix_only posix_right public
 .PHONY: rearguard_signatures rearguard_signatures_version

NEWS

@@ -1,5 +1,73 @@
 News for the tz database
 
+Release 2024a - 2024-02-01 09:28:56 -0800
+
+  Briefly:
+    Kazakhstan unifies on UTC+5 beginning 2024-03-01.
+    Palestine springs forward a week later after Ramadan.
+    zic no longer pretends to support indefinite-past DST.
+    localtime no longer mishandles Ciudad Juárez in 2422.
+
+  Changes to future timestamps
+
+    Kazakhstan unifies on UTC+5.  This affects Asia/Almaty and
+    Asia/Qostanay which together represent the eastern portion of the
+    country that will transition from UTC+6 on 2024-03-01 at 00:00 to
+    join the western portion.  (Thanks to Zhanbolat Raimbekov.)
+
+    Palestine springs forward a week later than previously predicted
+    in 2024 and 2025.  (Thanks to Heba Hamad.)  Change spring-forward
+    predictions to the second Saturday after Ramadan, not the first;
+    this also affects other predictions starting in 2039.
+
+  Changes to past timestamps
+
+    Asia/Ho_Chi_Minh's 1955-07-01 transition occurred at 01:00
+    not 00:00.  (Thanks to Đoàn Trần Công Danh.)
+
+    From 1947 through 1949, Toronto's transitions occurred at 02:00
+    not 00:00.  (Thanks to Chris Walton.)
+
+    In 1911 Miquelon adopted standard time on June 15, not May 15.
+
+  Changes to code
+
+    The FROM and TO columns of Rule lines can no longer be "minimum"
+    or an abbreviation of "minimum", because TZif files do not support
+    DST rules that extend into the indefinite past - although these
+    rules were supported when TZif files had only 32-bit data, this
+    stopped working when 64-bit TZif files were introduced in 1995.
+    This should not be a problem for realistic data, since DST was
+    first used in the 20th century.  As a transition aid, FROM columns
+    like "minimum" are now diagnosed and then treated as if they were
+    the year 1900; this should suffice for TZif files on old systems
+    with only 32-bit time_t, and it is more compatible with bugs in
+    2023c-and-earlier localtime.c.  (Problem reported by Yoshito
+    Umaoka.)
+
+    localtime and related functions no longer mishandle some
+    timestamps that occur about 400 years after a switch to a time
+    zone with a DST schedule.  In 2023d data this problem was visible
+    for some timestamps in November 2422, November 2822, etc. in
+    America/Ciudad_Juarez.  (Problem reported by Gilmore Davidson.)
+
+    strftime %s now uses tm_gmtoff if available.  (Problem and draft
+    patch reported by Dag-Erling Smørgrav.)
+
+  Changes to build procedure
+
+    The leap-seconds.list file is now copied from the IERS instead of
+    from its downstream counterpart at NIST, as the IERS version is
+    now in the public domain too and tends to be more up-to-date.
+    (Thanks to Martin Burnicki for liaisoning with the IERS.)
+
+  Changes to documentation
+
+    The strftime man page documents which struct tm members affect
+    which conversion specs, and that tzset is called.  (Problems
+    reported by Robert Elz and Steve Summit.)
+
+
 Release 2023d - 2023-12-21 20:02:24 -0800
 
   Briefly:

africa

@@ -30,6 +30,10 @@
 # Milne J. Civil time. Geogr J. 1899 Feb;13(2):173-94.
 # https://www.jstor.org/stable/1774359
 #
+# For the 1911/1912 establishment of standard time in French possessions, see:
+# Société Française de Physique, Recueil de constantes physiques (1913),
+# page 752, 18b.
+#
 # European-style abbreviations are commonly used along the Mediterranean.
 # For sub-Saharan Africa abbreviations were less standardized.
 # Previous editions of this database used WAT, CAT, SAT, and EAT
@@ -113,7 +117,7 @@ Zone Atlantic/Cape_Verde -1:34:04 -	LMT	1912 Jan 01  2:00u # Praia
 
 # Chad
 # Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
-Zone	Africa/Ndjamena	1:00:12 -	LMT	1912        # N'Djamena
+Zone	Africa/Ndjamena	1:00:12 -	LMT	1912 Jan  1 # N'Djamena
 			1:00	-	WAT	1979 Oct 14
 			1:00	1:00	WAST	1980 Mar  8
 			1:00	-	WAT
@@ -139,7 +143,7 @@ Zone	Africa/Ndjamena	1:00:12 -	LMT	1912        # N'Djamena
 #	Inaccessible, Nightingale: uninhabited
 
 # Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
-Zone	Africa/Abidjan	-0:16:08 -	LMT	1912
+Zone	Africa/Abidjan	-0:16:08 -	LMT	1912 Jan  1
 			 0:00	-	GMT
 
 ###############################################################################