remove_prefix
remove_prefix(bt, &key, dst->prefix.len);
remove_prefix(bt, &key, src->parent->prefix.len);
remove_prefix(bt, &key, dst->parent->prefix.len);
remove_prefix(bt, &key, dst->prefix.len);
remove_prefix(bt, &sepkey, mp->prefix.len);
remove_prefix(bt, &sepkey, pright->parent->prefix.len);
remove_prefix(bt, &rkey, pfx_diff);
static void remove_prefix(struct btree *bt, struct btval *key,
remove_prefix(bt, &xkey, mp->prefix.len);