Use of undefined constant nobody in smileys.php

2021/08/25 00:21:34 [error] 3571462#3571462: *41884864 FastCGI sent in stderr: "PHP message:
 PHP Warning: Use of undefined constant nobody - assumed 'nobody' (this will throw an Error in a future version of PHP) i
 /srv/studip_svn/4.6/app/controllers/smileys.php on line 35" while reading response header from upstream,
 request: "GET /dispatch.php/smileys/picker?cid=22b92fc243d02738e54a884ae043e920 HTTP/2.0"