generic-mode: Keywords also highlight with an underscore

[O. Wölfelschneider]

Hi group!

Say I did:

(define-generic-mode 'fnord-mode
  nil
  (list "fnord" "foobar")
  nil
  (list "\\.fnord")
  (list 'turn-on-font-lock))

This mode will then highlight the keywords fnord and foobar.

However, it will also highlight _fnord, foobar_ and so on.

I do not want the keyword to highlight if it has an
underscore attached to it.

How can I get rid of this behaviour?

(Emacs 21.4 that comes with debian sarge, also an older
20.7.1 on windows)

Thanks!
 Olav