rem: notify_debugger(int signal, struct sigaction *handler, bool deadly, cpu_status *state)
add: notify_debugger(struct thread *thread, int signal, struct sigaction *handler, bool deadly, cpu_status *state)
context: notify_debugger(int signal, struct sigaction *handler, bool deadly,	cpu_status *state){	bool result;	RELEASE_THREAD_LOCK();	restore_interrupts(*state);	result = user_debug_handle_signal(signal, handler, deadly);	*state = disable_interrupts();	GRAB_THREAD_LOCK();	return result;}