finish prototype of player handler updates

include/basin/inventory.h

@@ -49,6 +49,8 @@ struct inventory {
 	struct slot** slots;
 	size_t slot_count;
 	int window;
+	struct mempool* drag_pool;
+	struct llist* drag_slot;
 	struct hashmap* watching_players;
 	struct tile_entity* tile;
 	pthread_mutex_t mutex;

src/inventory.c

@@ -31,6 +31,9 @@ struct inventory* inventory_new(struct mempool* pool, int type, int id, size_t s
 	inv->type = type;
 	inv->window = id;
 	inv->watching_players = hashmap_thread_new(8, inv->pool);
+	inv->drag_pool = mempool_new();
+	pchild(inv->pool, inv->drag_pool);
+	inv->drag_slot = llist_new(inv->drag_pool);
 	pthread_mutex_init(&inv->mutex, NULL);
 	phook(inv->pool, (void (*)(void*)) pthread_mutex_destroy, &inv->mutex);
 	return inv;