fix for xf86-video-vesa with xserver 1.7

[Julien Cristau]

On Mon, Oct  5, 2009 at 22:48:46 +0200, Matthieu Herrb wrote:

> But master is still busted for me wrt slow bcopy. I'd prefer to see
> 5ef53a94ce4e48e11de26290cd677266308640c8 reverted on master too until a
> proper fix for Linux/alpha is proposed.
> 
<1254132223.12629.19.camel at omega> has a proposed fix for alpha.  Matt,
can you please have a look?

(http://article.gmane.org/gmane.comp.freedesktop.xorg.devel/2095)

Cheers,
Julien