static_assert
#ifndef static_assert
static_assert(IINNTT_MIN < INT_MIN && INT_MAX < IINNTT_MAX);
static_assert(TZ_CHANGE_INTERVAL < 0 || HAVE_SYS_STAT_H);
static_assert(tzdirslashlen <= PATH_MAX); /* Sanity check; assumed below. */
static_assert(! TYPE_SIGNED(time_t) || ! SIGNED_PADDING_CHECK_NEEDED
#if __STDC_VERSION__ < 202311 && !defined static_assert
static_assert(MKTIME_MIGHT_OVERFLOW