Currently only modern POSIX systems are supported; it has been tested mainly on Linux, FreeBSD and OSX. Please send information if it fails on a particular BSD system. It is likely to work with DragonFlyBSD. NetBSD and OpenBSD probably need DILL_THREAD_FALLBACK to work as Thread Local Storage is unsupported.
Cygwin is very broken, it does not support AF_UNIX properly so no development will progress further with this platform.