Implement THREAD_PRIORITY_TIME_CRITICAL

[Mike Hearn]

> Until it crashes your box of course... 

If a Windows program has a habit of hard freezing the system then the 
user will learn not to run that program.

As it is, right now _many_ games suffer this problem with corrupted 
audio and it's very unpleasant (loud bursts of white noise). Makes the 
games unplayable, in fact.

I'd rather make the games playable and give developers an incentive to 
find a better privilege model than leave this to coast along for another 
few years with only a bunch of talk, ideas and non-mainline patches.

Right now there are no good solutions for this we can implement in Wine 
itself (except maybe making wineserver suid root and drop privs), and 
SCHED_ISO isn't merged into the mainline kernel, so telling users to 
upgrade won't solve much.

> If we have to require people to upgrade their kernel to get
> the feature that's fine; at least then when the box dies we can blame
> the kernel guys ;-)

I agree that it's not good, but this patch makes the best of a bad 
situation and it's better for the users this way. If they don't want to 
run as root, they don't have to, and if - like me - they know the game 
is safe and wish to have some fun this evening then they can.

thanks -mike