feat: gc-arena (WIP, does not compile)

src/lib.rs

@@ -1,6 +1,8 @@
 #![cfg_attr(test, feature(test))]
 #![allow(dead_code)]
+
 #![feature(iter_collect_into)]
+#![feature(arbitrary_self_types)]
 
 mod builtins;
 mod bytecode;