As you can tell, the Windows port for QUARK is out of date.
We implemented a subset of the Pthreads so that users would not have to
be concerned with installing their own threads library.
However, we don't have the resources to focus on the Windows port at
present, but there may be a couple of simple (untested by us) solutions.
You could consider linking with the Pthread-Win32 library (LGPL licensed)
Or, there is a header based implementation that should be an easy drop-in.
Replace quarkwinthread.h with the file at
http://locklessinc.com/articles/pthreads_on_windows/ (BSD licensed)
Remove quarkwinthread.c from the build.
Please let us know if these suggestions worked for you.