[1/5] winex11: Load the XComposite extension when available

[Chris Robinson]

On Sunday 23 September 2007 02:20:06 pm you wrote:
> It should be off by default until users will have enough time to test if
> it's working properly.
>
> Vitaliy.

This patch itself does nothing but load the XComposite lib and its functions. 
It's up to the subsystems themselves to do with it what they will (hence why 
there's the GL-specific compositing option).