PackTime procedure

  DECLARATION:  PackTime(Var DTValue : DateTime; Var ETime : LongInt);

      PURPOSE:  Converts a DateTime record into a 4-byte, packed
                Date-and-Time LongInt used by SetFTime.

         UNIT:  DOS

      REMARKS:  The DateTime type is declared in the DOS unit as follows:

                    Type
                       DateTime = Record
                          Year, Month, Day, Hour, Min, Sec : Integer;
                       End;

                Valid ranges for the fields in the DateTime record are:

                    Year 1980..2099     Month 1..12     Day 1..31
                    Hour 0..23          Min 0..59       Sec 0..59