First add for test tools.

dev/test/testutf.php

+<?php
+// This source file must be UTF-8 encoded
+
+$filename='filewithé';
+
+print 'Test to create a file on disk'."\n";
+$s=fopen('/tmp/'.$filename,'w');
+fclose($s);
+
+print 'Files has been created. Check its name from your explorer'."\n";
+?>
\ No newline at end of file