@samdark actually, it would. Before this pull request, @qiangxue already introduce :
```
			if ($flag == (SORT_STRING | SORT_FLAG_CASE)) {
				$flag = SORT_STRING;
				$column = array();
				foreach (static::getColumn($array, $key) as $k => $value) {
					$column[$k] = strtolower($value);
				}
				$args[] = $column;
			}
```
which mean, `SORT_FLAG_CASE` would never passed into the real `array_multisort` function anyway. My pull request just fix undefined constant in any machine with php prior to version 5.4.