Wine needs to setup each thread that has an access to Windows APIs. It means that in winelib builds, we can't let standard C++ library create threads and need to use Wine for that instead. I wrote a thin wrapper around Windows thread functions so that the rest of code just has to use new dxvk::thread class instead of std::thread.
Since we are synchronizing once per frame anyway, there is no need to
artificially limit the number of chunks in flight. Applications which
use deferred contexts and submit a large number of CS chunks through
command lists may benefit from this optimization.
Improves overall frame rate and latency in situations where the
application's render thread cannot keep up with the CS thread.
Considerable frametime improvements in NieR:Automata and
slightly higher frame rates in The Witcher 3.
While these are not being used as of yet, these classes can be
used to implement command stream multithreading in the future.
They are also useful to implement command lists for deferred
contexts, which are a core feature of D3D11.
