A minor update for Top-20 Maclisp

[Martin David Connor <MARTY at MIT-MC>]

I found the following in MC:L;STATUS >

Specifically in the (sstatus ttyint ... ) code:
	...

SSTIN1:	HRRM B,(TT)
	...
IFN D20,[
	POP P,TT		;RESTORE TTSAR
	ROT F,1			;RESTORE CHARACTER
	CAIE F,3		;DON'T ALLOW USE TO ASSIGN ^C
==>	 CAILE F,26.		;TOPS-20 ONLY SUPPORTS TO ^Z
|	  JRST UNLKTRUE		;RETURN TRUE, BUT DON'T DO TELL THE OP SYS
|	     ...
|
= Well, this perhaps used to be true, but is no longer. these days,
  one can assign several other characters.

  I think the update I would suggest is to remove the test altogether,
  since the bit values for the interrupt word on the 20 after the
  altmode would have to be special cased.

  For my particular application I need to get control at interrupt

  I made myself a patched lisp until this is changed, and I indeed am
  able to get the altmode interrupt properly.