Old-style backquotes don't work with Emacs 27 or later. Remove the
code altogether, because it is no longer needed since Emacs 20.1.

--- gnuserv-3.12.8/gnuserv-compat.el
+++ gnuserv-3.12.8/gnuserv-compat.el
@@ -180,25 +180,6 @@
   (defun frame-totally-visible-p (frame)
     (eq t (frame-visible-p frame))))
 
-;; Make custom stuff work even without customize
-;;   Courtesy of Hrvoje Niksic <hniksic@srce.hr>
-;;   via Ronan Waide <waider@scope.ie>.
-(eval-and-compile
-  (condition-case ()
-      (require 'custom)
-    (error nil))
-  (if (and (featurep 'custom) (fboundp 'custom-declare-variable))
-      nil ;; We've got what we needed
-    ;; We have the old custom-library, hack around it!
-    (defmacro defgroup (&rest args)
-      nil)
-    (defmacro defcustom (var value doc &rest args)
-      (` (defvar (, var) (, value) (, doc))))
-    (defmacro defface (var value doc &rest args)
-      (` (make-face (, var))))
-    (defmacro define-widget (&rest args)
-      nil)))
-
 ;; Now for gnuserv...
 (require 'gnuserv)