(cons 'if (cons cond (cons nil body))))
;; (def-edebug-spec unless (&rest form))
+(defvar-maybe frame-background-mode nil
+ "*The brightness of the background.
+Set this to the symbol dark if your background color is dark, light if
+your background is light, or nil (default) if you want Emacs to
+examine the brightness for you. However, the old Emacsen might not
+examine the brightness, so you should set this value definitely.")
+
;;; @ Emacs 19.23 emulation
;;;