fix: function returns by const value

src/logic/scripting/lua/LuaState.cpp

@@ -68,7 +68,7 @@ LuaState::LuaState() {
     setglobal(LAMBDAS_TABLE);
 }
 
-const std::string LuaState::envName(int env) {
+std::string LuaState::envName(int env) {
     return "_ENV"+util::mangleid(env);
 }
 

src/logic/scripting/lua/LuaState.hpp

@@ -29,7 +29,7 @@ namespace lua {
         LuaState();
         ~LuaState();
 
-        static const std::string envName(int env);
+        static std::string envName(int env);
         void loadbuffer(int env, const std::string& src, const std::string& file);
         int gettop() const;
         int pushivec3(lua_Integer x, lua_Integer y, lua_Integer z);