unsupported ioctls in 4.2: TIOCMODG ?

[Matt Crawford]

The drivers for the terminal multiplexors under 4.2 seem to support a set
of ioctls which set/get the modem bits.  The front end sys/tty.c does not
have them in its big switch statement, so 
	retn = ioctl(1, TIOCMODG, &bits);
returns -1.  I have a need for this call.  Can I just add a few cases to
the switch, or are these left out because they won't work?  Thanks for any
info available.
___________________________________________________________
Matt		University	ARPA: crawford at anl-mcs.arpa
Crawford	of Chicago	UUCP: ihnp4!oddjob!matt