define POSIX specified minimum TZ abbr size 3 TZNAME_MIN use limits.h TZNAME_MAX, _POSIX_TZNAME_MAX, unistd.h sysconf(_SC_TZNAME_MAX) issue error if no symbols defined (document fallback value in case required) allow POSIX angle bracket < > quoted signed alphanumeric tz abbr e.g. allow POSIX unquoted alphabetic tz abbr e.g. MESZ apply same changes for DST tz abbr --- newlib/libc/time/tzset_r.c | 74 ++++++++++++++++++++++++++++++++------ 1 file changed, 64 insertions(+), 10 deletions(-)