Right now this project just builds a stub version (that compiles, but throws a runtime error if actually used) on platforms like OS X and Windows i.e. anywhere where the Linux SPI module does not exist.
For Windows 10 though, say running on RasPi 2, there is a set of "IoT" interfaces, including SPI: https://msdn.microsoft.com/en-us/library/windows/apps/windows.devices.spi.aspx