* process.c: Make sure we don't miss processes exiting, by having

* process.c: Make sure we don't miss processes exiting, by having
	the sigchld handler clear *input_available_clear_time.
	(wait_reading_process_input): Check for process activity after
	setting the timeout and calling set_waiting_for_input.
	(sigchld_handler): If the process which has exited is one we care
	about, clear *input_available_clear_time.

	* process.c (process_send_signal): Use TERMIOS functions in
	preference to BSD ioctls.  Some systems attempt to provide the BSD
	functions for backward compatibility, and get it wrong.