gc_free
gc_free(thmap, THMAP_GETOFF(thmap, &gc->data[0]), gc->len);
gc_free(thmap, root, THMAP_ROOT_LEN);
gc_free(thmap, leaf_off, sizeof(thmap_leaf_t));
gc_free(thmap, leaf->key, leaf->len);
gc_free(thmap, THMAP_GETOFF(thmap, leaf), sizeof(thmap_leaf_t));
gc_free(thmap, nptr, THMAP_INODE_LEN);