Various fixes.

	B - fixed usage, DISPLAY :0 vs :0.0
	9term - fixed various terminal things
	rc - notice traps in Read
	_p9dir - only run disk code for disks
	dirread - getdirentries on FreeBSD and Linux
		are different w.r.t. meaning of off.
	notify - set up so signals interrupt system calls
	bprint - use bfmt.