(defun byte-optimize-featurep (form)
;; Emacs-21's byte-code doesn't run under XEmacs or SXEmacs anyway, so we
;; can safely optimize away this test.
- (if (member (cdr-safe form) '((quote xemacs) (quote sxemacs)))
+ (if (member (cdr-safe form) '(((quote xemacs)) ((quote sxemacs))))
nil
form))