I've made some documentation
for getting the current state of libmapper building on windows, as well as building the mpr.device external for Max 8. It requires quite a bit of hacks, but the instructions should get you there, and have links to everything you should need.
Currently, building the max external is a lot quicker since I was able to use cmake to generate visual studio solutions, and I'm hoping to modify the libmapper build to do the same thing soon. The same goes for the rest of the externals that I haven't gotten to as well.
After that's done, hopefully we can try and package everything in a .msi installer :)
If anyone ends up trying the instructions, I'd appreciate some feedback about how the process was for you or any problems encountered.