FIX: to kernel/sys/dev/dhdm.c and kernel/sys/dev/dz.c

[utzoo!decvax!ucbvax!dist2]

	Although kernel/src/cmd/stty.c supports the LNOHANG local mode bit,
the drivers themselves ignored its state.  The fixes necessary to make them
work correctly are:

	diff kernel/sys/dev/dhdm.c.old kernel/sys/dev/dhdm.c
	116c116,117
	< 				if ((tp->t_state&WOPEN)==0) {
	---
	> 				if ((tp->t_state&WOPEN)==0 &&
	> 				    (tp->t_local&LNOHANG)==0) {

	diff kernel/sys/dev/dz.c.old kernel/sys/dev/dz.c
	304c304,305
	< 			if (tp->t_state&CARR_ON) {
	---
	> 			if ((tp->t_state&CARR_ON) &&
	> 			    (tp->t_local&LNOHANG)==0) {

These fixes should be applied to all tapes written before 10/9/81.

			Carl