Connect a signal to a pike function.
This function differs from the signal_connect function in how it
calls the callback function.
The old interface:
void signal_handler( mixed my_arg, GTK.Object object,
mixed ... signal_arguments )
The new interface:
void signal_handler( mixed ... signal_arguments,
mixed my_arg, GTK.Object object )
The return value of this function can be used to remove a signal
with signal_disconnect, and block and unblock the signal will
signal_block and signal_unblock.