Fix for 2 echolines bug in TECO on Tops-20 with VTS

[Martin David Connor <MARTY%MIT-OZ@MIT-MC.ARPA>]

In VTS systems on Tops-20 the following bug happens when there are 2
echolines and the terminal is in WRAP mode.
If you type a carriage return to a prompt, sometimes the response will
WRAP to the top of the screen and kill the top line.  Since EMACS
doesn't expect this (as it should not), I sought a bug fix for it.

The following fix is from from Leonard N. Zubkoff at CMU and has been
working fine in the version of TECO he maintains.

Here is the place where the fix needs to be applied:

    ; DO INITIAL SETUP
    SETTTM: SAVE C
	    MOVSI A,.TICCG	; ^G ON CHANNEL 0
	    SKIPG NOQUIT	; IF QUITTING IS ALWAYS DISABLED DO NOT ARM ATI
	     ATI		; ^G, SO THAT IT WILL ARRIVE AS A COMMAND AT
				; THE CORRECT TIME (THIS IS FOR RMODE).
	    CALL DOSTIW		; SETUP TERMINAL INT MASK
	    MOVEI A,.CTTRM
	    RTMOD%		;[NEW] Read VTS Terminal Mode Word (Jsys 636)
	     ERJMP .+4		;[NEW] No VTS.
	    TLO B,(TM%SCR)	;[NEW] Turn off Wrap Mode (200000,,0)
	    STMOD%		;[NEW] Set VTS Terminal Mode Word (Jsys 637)
	     ERJMP .+1		;[NEW] No VTS.
	    RFMOD		; GET TTY MODE WORD
	    SKIPE CH,RGETTY	; PRINTING?
	     TRZA 2,TT%DAM	; NO, BINARY MODE THEN
	      TRO 2,1_6\TT%ECO	; YES, MAKE SURE DATA MODE NORMAL

			. . . .

Installing this fix will greatly help people who would like to use 2
echoline mode all the time.

Could someone please install it in the OZ version of TECO, or explain
to me the procedure for doing it?