Gets the local time zone label and offset from GMT, given utc.
    Format
      #include <utc.h>
      int utc_localzone(*tzname, tzlen, *tdf, *isdst, *utc)
         char *tzname;
         size_t tzlen;
         long *tdf;
         int *isdst;
         const utc_t *utc;
      #include <utc.h>
      int utc_localzone(*tzname, tzlen, *tdf, *isdst, *utc)
1 – Parameters
    Input
 tzlen
    Length of the tzname buffer.
 utc
    Binary timestamp.
    Output
 tzname
    Character string long enough to hold the time zone label.
 tdf
    Longword with differential in seconds east or west of GMT.
 isdst
    Integer with a value of zero if standard time is in effect or a
    value of 1 if daylight savings time is in effect.
2 – Description
    The Local Zone routine gets the local time zone label and offset
    from GMT, given utc.
    OpenVMS systems do not have a default time zone rule. You
    select a time zone by defining sys$timezone_rule during the
    sys$manager:net$configure.com procedure, or by explicitly
    defining sys$timezone_rule.
3 – Notes
    All of the output parameters are optional. No value is returned
    and no error occurs if the pointer is null.
4 – Returns
     0   Indicates that the routine executed successfully.
    -1   Indicates an invalid time argument or an insufficient buffer.
5 – Example
See the sample program for the utc_gmtzone routine.
6 – Related Functions
utc_anyzone, utc_gmtzone, utc_localtime