Results of setegid()/setegid() not checked

Hello,

It seems tha the results of setegid()/setegid() are not checked:

cups.c: In function ‘_cph_cups_set_effective_id’:
cups.c:582:25: error: ignoring return value of ‘setegid’, declared with attribute warn_unused_result [-Werror=unused-result]
  582 |                         setegid (getgid ());
      |                         ^~~~~~~~~~~~~~~~~~~
cups.c:592:25: error: ignoring return value of ‘setegid’, declared with attribute warn_unused_result [-Werror=unused-result]
  592 |                         setegid (getgid ());
      |                         ^~~~~~~~~~~~~~~~~~~
cups.c: In function ‘_cph_cups_reset_effective_id’:
cups.c:610:9: error: ignoring return value of ‘seteuid’, declared with attribute warn_unused_result [-Werror=unused-result]
  610 |         seteuid (getuid ());
      |         ^~~~~~~~~~~~~~~~~~~
cups.c:611:9: error: ignoring return value of ‘setegid’, declared with attribute warn_unused_result [-Werror=unused-result]
  611 |         setegid (getgid ());
      |         ^~~~~~~~~~~~~~~~~~~
cc1: all warnings being treated as errors

According to the man page this is a grave security error:

Note: there are cases where seteuid() can fail even when the caller is UID 0; it is a grave security error to omit checking for a failure return from seteuid().