rem: error (EXIT_FAILURE, errno, _("cannot set user id"));
add: error (EXIT_FAIL, errno, _("cannot set user id"));
context: change_identity (const struct passwd *pw){#ifdef HAVE_INITGROUPS  errno = 0;  if (initgroups (pw->pw_name, pw->pw_gid) == -1)    error (EXIT_FAILURE, errno, _("cannot set groups"));  endgrent ();#endif  if (setgid (pw->pw_gid))    error (EXIT_FAILURE, errno, _("cannot set group id"));  if (setuid (pw->pw_uid))    error (EXIT_FAILURE, errno, _("cannot set user id"));}