Implement THREAD_PRIORITY_TIME_CRITICAL

[Mike Hearn]

> Is it kernel dependant? Does 2.6.11 for example exhibit the problem or only 
> recent kernels? Or has noone tried an older kernel like that?

I think this has been a problem since time immemorial. Previous 
discussions like this one have always gone around in the same circle - 
it needs root what do we do oh dear i guess we'll do nothing.

The discussion has only started again in the last few days because I sat 
down and produced a patch that fixes the games, and prints a "Please run 
Wine as root to fix this game" message to the console.

So, we appear to be at an impasse:

*  Alexandre doesn't want something that requires root.
*  The mainline kernel won't be getting SCHED_ISO.
*  Fixing the apps (assuming that is the problem) is likely to be
    mind-blowingly hard.

Potentially some solution can be figured out in Wine itself, but I've 
not seen any good suggestions yet.

I think for now I shall just maintain this patch out of tree so savvy 
users can apply it and get glitch-free audio. I have never been 
convinced by this sacred devotion to avoiding SCHED_FIFO: the 
restrictions behind it make total sense on a server where you have 
multiple users who may be untrusted. I doubt most end-users care on a 
desktop with a readily accessible reset button. A game goes batty and 
hangs the machine - oh well, hit reset and don't play it again. Problem 
solved.

thanks -mike