Cygwin/X

Cygwin/X consists of an X server, X libraries, and nearly all of the standard X clients, such as xterm, xhost, xdpyinfo, xclock, xeyes, etc.

Cygwin/X, as the name implies, uses the Cygwin project which provides a UNIX-like API to Xlib and X clients, thereby minimizing the amount of porting required.