Unfortunately at the moment the wrapper contains code that is specific to Windows, but that could be stripped out - the real problem is that the only version of the CLR that supports direct native interop using C++/CLI is Microsoft's, and even then only the full version available on Windows (not the reduced frameworks on Windows Phone and Xbox 360).
I did some research while developing the wrapper to see if I could get it to work in Mono but was disappointed to find that Mono doesn't support the mixed-mode assemblies. That almost led me to drop the whole thing as I was rather disheartened, but I was getting a little tired of not finishing anything
EDIT: Since that was a little technical, to clarify, as-is it is highly unlikely this wrapper will ever be able to support other platforms. Something like standard P/Invoke might be possible with Mono, but I haven't had the time to look into an alternative solution.