Slowly add more statements and expressions; Add header file

src/entity.cpp

@@ -2,6 +2,7 @@ struct Scope;
 struct Checker;
 struct Type;
 struct DeclInfo;
+struct lbModule;
 
 
 #define ENTITY_KINDS \
@@ -104,6 +105,8 @@ struct Entity {
 	Entity *    using_parent;
 	Ast *       using_expr;
 
+	lbModule *  code_gen_module;
+
 	isize       order_in_src;
 	String      deprecated_message;