The Windows build is using https://github.com/libusbx/libusbx 33ba1231a1b07425eaa83935f84b2e4b7f904f35 and http://sources.redhat.com/pthreads-win32/ cvs See the corresponding COPYING* files for the license text. You might need to grab the runtime from http://www.microsoft.com/en-us/download/details.aspx?id=8328 or http://www.microsoft.com/en-us/download/details.aspx?id=13523