- strlen handles utf8 strings correctly

lua.cpp

@@ -564,7 +564,7 @@ extern "C" {
     }
     static int cpp_strlen(lua_State *L) {
         const char* str = luaL_checkstring(L, 1);
-        lua_pushinteger(L, strlen(str));
+        lua_pushinteger(L, utfstrlen(str));
         return 1;
     }