add intrinsic functions

At least from the intrinsic function amendment to COBOL85, but ideally all that are supported in Enterprise COBOL for z/OS.

Currently getting:

gcobol -fmax-errors=99 dice.cob
cobol1: syntax error, dice.cob line 14 at 'FUNCTION'
cobol1: error: failed compiling dice.cob

with the code

       IDENTIFICATION DIVISION.
       PROGRAM-ID. dice-roller.

       DATA DIVISION.
       WORKING-STORAGE SECTION.
       01  result-tally.
           03  result-tallies           PIC 9(7) OCCURS 6 TIMES
                                        INDEXED BY tally-idx.

       01  random-number                       PIC 9 COMP.

       PROCEDURE DIVISION.
           MOVE FUNCTION RANDOM(FUNCTION SECONDS-PAST-MIDNIGHT)
           TO random-number

       PERFORM 1000000 TIMES
         COMPUTE random-number = FUNCTION RANDOM * 6
         ADD 1 TO random-number
         ADD 1 TO result-tallies (random-number)
       END-PERFORM

       PERFORM VARYING tally-idx FROM 1 BY 1 UNTIL tally-idx > 6
          DISPLAY tally-idx ": " result-tallies (tally-idx)
       END-PERFORM
       GOBACK.