Import of CCTZ from GitHub.

PiperOrigin-RevId: 518850294
Change-Id: I3e9dcce5de2ae878d0992f05c0f39ccaf10a1ac5

absl/time/internal/cctz/src/tzfile.h

@@ -102,20 +102,24 @@ struct tzhead {
 */
 
 #ifndef TZ_MAX_TIMES
+/* This must be at least 242 for Europe/London with 'zic -b fat'.  */
 #define TZ_MAX_TIMES 2000
 #endif /* !defined TZ_MAX_TIMES */
 
 #ifndef TZ_MAX_TYPES
-/* This must be at least 17 for Europe/Samara and Europe/Vilnius.  */
+/* This must be at least 18 for Europe/Vilnius with 'zic -b fat'.  */
 #define TZ_MAX_TYPES 256 /* Limited by what (unsigned char)'s can hold */
 #endif                   /* !defined TZ_MAX_TYPES */
 
 #ifndef TZ_MAX_CHARS
+/* This must be at least 40 for America/Anchorage.  */
 #define TZ_MAX_CHARS 50 /* Maximum number of abbreviation characters */
                         /* (limited by what unsigned chars can hold) */
 #endif                  /* !defined TZ_MAX_CHARS */
 
 #ifndef TZ_MAX_LEAPS
+/* This must be at least 27 for leap seconds from 1972 through mid-2023.
+   There's a plan to discontinue leap seconds by 2035.  */
 #define TZ_MAX_LEAPS 50 /* Maximum number of leap second corrections */
 #endif                  /* !defined TZ_MAX_LEAPS */
 

absl/time/internal/cctz/testdata/version

-2022g
+2023a

absl/time/internal/cctz/testdata/zoneinfo/iso3166.tab

@@ -238,7 +238,7 @@ SY	Syria
 SZ	Eswatini (Swaziland)
 TC	Turks & Caicos Is
 TD	Chad
-TF	French Southern Territories
+TF	French S. Terr.
 TG	Togo
 TH	Thailand
 TJ	Tajikistan