define Macros automatically for hide-ifdef-mode

[Fang lun gang]

I'm reading a lot of code recently. Since there are many "ifdef"s, I
would like to use hide-ifdef-mode to hide some of them. However,
hide-ifdef regards all those Macros undefined by default. Therefore,
it hides all "ifdef" blocks.

But what I want is: if not explicitly specified, a "ifdef" block won't
been hidden. That is to say, all Macros are assumed to be defined.

Setting hide-ifdef-use-define-alist is not affordable since there are
so many Macros.

;; (add-hook 'hide-ifdef-mode-hook
;;      (lambda ()
;;       (unless hide-ifdef-define-alist
;;         (setq hide-ifdef-define-alist
;;              '((list1 ONE TWO)
;;                (list2 TWO THREE))))
;;       (hide-ifdef-use-define-alist 'list2))) ; use list2 by default
;;

Does hide-ifdef provides any customization for that? 
Or do I have to hacking the hideif.el ? If I do, how should I do then?

Thanks for your help in advance.

-- 
Fang lun gang