* NEWS, libmisc/chowntty.c, libmisc/utmp.c: is_my_tty() moved from

utmp.c to chowntty.c. checkutmp() now only uses an existing utmp
	entry if the pid matches and ut_line matches with the current tty.
	This fixes a possible DOS when entries can be forged in the utmp
	file.
	* libmisc/chowntty.c, src/login.c, lib/prototypes.h: Remove the
	tty argument from chown_tty. chown_tty always changes stdin and
	does not need this argument anymore.

src/login.c

@@ -1094,7 +1094,7 @@ int main (int argc, char **argv)
 	}
 	setup_limits (&pwent);	/* nice, ulimit etc. */
 #endif				/* ! USE_PAM */
-	chown_tty (tty, &pwent);
+	chown_tty (&pwent);
 
 #ifdef USE_PAM
 	/*