rem: struct thread *t = (struct thread *)thr; if (!t) t = thread_get_current_thread(); return (t->sig_pending & ~t->sig_block_mask);
add: struct thread *thread = (struct thread *)_thread; if (thread == NULL) thread = thread_get_current_thread();  return thread->sig_pending & ~thread->sig_block_mask;
context: has_signals_pending(void *thr){	struct thread *t = (struct thread *)thr;	if (!t)		t = thread_get_current_thread();	return (t->sig_pending & ~t->sig_block_mask);}