Support default __stdcall calling convention on tests as well

tests/print_value.c

@@ -90,7 +90,7 @@ static void print_value_should_print_object(void)
     assert_print_value("{}");
 }
 
-int main(void)
+int CJSON_CDECL main(void)
 {
     /* initialize cJSON item */
     UNITY_BEGIN();