Bug in select for ttys

[Scooter Morris%John Gardi]

Subject: select system call does not work for ttys when DH_SOFTCAR is defined
Index:	sys/dev/tty.c 2.9bsd

Description:
	When a system has a DH driver and DH_SOFTCAR is defined, the select
	system call fails for ttys which have the softcar bit set.
Repeat-By:
	Try a select on a tty with a softcar bit set.  The results will
	be sporadic at best, but will never work correctly.
Fix:
	The problem is in the ttselect() routine when it assigns the
	pointer to the tty structure.  It uses the minor(dev) macro
	which strips the lower 8 bits off of the device number.  If the
	tty has the soft carrier bit (128) set, however, the pointer
	returned is off in never-never-land.  I just included dh.h in
	tty.c and if DH_SOFTCAR is set replaced minor(dev) with 
	minor(dev)&0177.