As multi-tty no longer does `FD_SET (0, &input_wait_mask)' in
process.c, if no `add_keyboard_wait_descriptor' calls are made, then
Carbon Emacs reads events from the window system only rarely via
polling with SIGALRM and becomes very unresponsive as reported.
    

Mitsuharu, can you tell us if you think this problem can be solved
easily?