Implemention of LockWindowUpdate

[Mike Hearn]

On Tue, 13 Jan 2004 00:10:20 +0000, Mike Hearn wrote:
> This patch makes the halflife menu screen look a bit better, with less
> flashing. Unfortunately it also makes it feel a bit slower, but I think
> that's just an optical illusion caused by less screen activity. The
> bottleneck is elsewhere.

Just had a hunch, and yes, switching off XRender and antialiasing speeds
things up nicely. I guess I should yell at keithp or something.... :)