pop_item           46 mergesort.c    			list = curr = pop_item(&q, get_next_fn);
pop_item           48 mergesort.c    			list = curr = pop_item(&p, get_next_fn);
pop_item           55 mergesort.c    					curr = pop_item(&q, get_next_fn);
pop_item           57 mergesort.c    					curr = pop_item(&p, get_next_fn);
pop_item           59 mergesort.c    					curr = pop_item(&q, get_next_fn);
pop_item           61 mergesort.c    					curr = pop_item(&p, get_next_fn);