TIOCFLUSH now uses 3rd arg

[tef at ucsfcgl.UUCP]

Subject: TIOCFLUSH now uses 3rd argument
Index:	/usr/man/man4/tty.4,/usr/src/etc/init.c,/usr/src/usr.bin/uucp/condevs.c

Description:
	The tty.4 manual page sez that TIOCFLUSH ignores the 'arg'
	argument.  Well, the way I read the code this is no longer
	true.  The 'arg' argument is now the address of an int which
	is taken as a flags word.  Flags should equal FREAD, FWRITE,
	FREAD|FWRITE, or 0 (which means the same as FREAD|FRWITE).
Repeat-By:
	Read code in ioctl.h, see that TIOCFLUSH uses the _IOW macro
	and that sys_generic copies in an int worth of data.
Fix:
	Change the documentation to reflect the code.
	Fix all the programs (like init) which used to just have
	"0" as the 3rd parameter to the ioctl.  Note that "0"
	now means location 0 of your address space, so that this
	bug would have been noticed much sooner if page 0 was
	not in your address space (where have I heard this before?).