rem: struct thread *thread_get_thread_struct(thread_id id)
add: thread_get_thread_struct(thread_id id)
context: struct thread *thread_get_thread_struct(thread_id id){	struct thread *t;	int state;	state = disable_interrupts();	GRAB_THREAD_LOCK();	t = thread_get_thread_struct_locked(id);	RELEASE_THREAD_LOCK();	restore_interrupts(state);	return t;}