Steven Kreuzer
777fb61a94
Changes: * The northern edge of Chihuahua changes to US timekeeping. * Much of Greenland stops changing clocks after March 2023. * Fix some pre-1996 timestamps in northern Canada. * C89 is now deprecated; please use C99 or later. * Portability fixes for AIX, libintl, MS-Windows, musl, z/OS * In C code, use more C23 features if available. * C23 timegm now supported by default * Fixes for unlikely integer overflows