I think that this should probably work, mostly.  For its “user interface”, the utility uses POSIX getopt(3) functionality, and also the BSD-style (also available on Linux).  I don’t know to deal with that on Windows.  Otherwise, it is just STDC.

I myself can’t test MSVC compilation; for I have no Windows in my house.  Please let me know what results you get.

Should there be indicators of demand, I may try to produce Windows binaries with mingw. 

If you need to replace anything with code from WIN32, I strongly suggest that you #define WIN32_LEAN_AND_MEAN.  I seem to vaguely also remember some define for Unicode, but I don’t remember what it is.  If somebody comes up with Windows/MSVC compat code, I may try to abstract that into a separate file.  I will not clutter main files with #ifdefed Windows code, or Windows “decorations”; I was recently trying to audit a simple cross-platform library where every function is “decorated” with DLLEXPORT, and that junk makes code unreadable.