Patch adding supoort for X Double Buffer extension

[Samuel Rydh]

On Sun, Apr 11, 2004 at 10:51:14PM -0700, dojothemouse@mac.com wrote:
> The OS might want to double buffer any X window for compositing... is 
> that what this X feature is for? Does supporting the X Double Buffer 
> *force* double buffering, or just allow it?
> 
> (P.S. I don't know what I'm talking about.)

The OS might do this anyway if it wants to; this has nothing to do with
the X double buffer extensions which is all about client double buffering.

The things is that MOL _already_ uses a kind of double buffering since the
X framebuffer is stored in RAM and one has to blit the modified area
explicitly. If uses the double buffer extension, the video data has
to be buffered thrice...

/Samuel