only in patch2:
unchanged:
--- gettext-0.17.orig/gettext-tools/misc/po-mode.el
+++ gettext-0.17/gettext-tools/misc/po-mode.el
@@ -101,7 +101,7 @@
     (defmacro defgroup (&rest args)
       nil)
     (defmacro defcustom (var value doc &rest args)
-      (` (defvar (, var) (, value) (, doc))))))
+      `(defvar ,var ,value ,doc))))
 
 ;;; Customisation.