Yeah, I haven't tried building it on MSVC. I used a bunch of c99 stuff so I wasn't sure how it would behave and I don't have an environment to test it on. Some of the logging stuff just won't work.
Have a look at hdr_time.h, that is the one place where I have an OS #ifdef, so it will probably cause a compile failure on windows. If you know an equivalent function on Windows I'd be happy to include it.