The decc$fix_time routine converts an OpenVMS binary system time
    (a 64-bit quadword containing the number of 100-nanosecond ticks
    since 00:00 November 17, 1858) to a UNIX binary time (a longword
    containing the number of seconds since 00:00 January 1, 1970).
    This routine is useful for converting binary times returned by
    OpenVMS system services and RMS services to the format used by
    some Compaq C RTL routines, such as ctime and localtime.