Codechange: [Script] Improve copying a list into another empty list.

src/script/api/script_list.cpp

@@ -557,12 +557,19 @@ void ScriptList::AddList(ScriptList *list)
 {
 	if (list == this) return;
 
+	if (this->IsEmpty()) {
+		/* If this is empty, we can just take the items of the other list as is. */
+		this->items = list->items;
+		this->buckets = list->buckets;
+		this->modifications++;
+	} else {
 		ScriptListMap *list_items = &list->items;
 		for (ScriptListMap::iterator iter = list_items->begin(); iter != list_items->end(); iter++) {
 			this->AddItem((*iter).first);
 			this->SetValue((*iter).first, (*iter).second);
 		}
 	}
+}
 
 void ScriptList::SwapList(ScriptList *list)
 {