optimize(env): single arg

src/builtins/mod.rs

@@ -60,5 +60,5 @@ pub fn env<'jit, 'vm>(vm: &'vm VM<'jit>) -> LetEnv<'jit, 'vm> {
     let builtins = Value::AttrSet(attrs);
 
     env_map.insert(sym, builtins);
-    LetEnv::new(env_map.into())
+    LetEnv::new(AttrSet::new(env_map).into())
 }