At least, do not port my software to Windows.
While the GNU General Public License expressly prohibits me from denying you the freedom to port software protected by it to Windows, I feel that you do great damage to the world if you do. Let me explain.
Windows is a proprietary environment. They don't give you the source code, and they do anything in their power to limit your freedom. They even try to limit what you can do with the software you rightfully bought from them. So, supporting them in any way is bad for the world, because it encourages others to try to limit others' freedoms (it worked great for Microsoft, so it must be a good idea, right?).
I don't want any of my work to give anyone a reason to support companies like Microsoft who try to limit people's freedoms.
That's why I develop my software on a completely free platform. So I know it works on a completely free platform. Many people using Windows don't care about their freedom. They do care about quality software and for that reason try to replace all the user space software from Microsoft with better free alternatives. This is the sole reason for the existance of cygwin.
However, giving people a way to work around bugs in Windows makes them stay longer with Windows. That's why I consider porting software to Windows sabotage. It does not help people under Windows, in the contrary. It makes them stay longer with Windows. And while they stay, they will put pressure on others to also use Windows. It only helps Microsoft.
While this text singles out Microsoft, other companies are equally evil. For example, porting the diet libc to Solaris would help Sun, noone else. Don't do it.
In the same line of argumentation, I will not modify any of my software so it works better with proprietary development platforms like Visual C++, even if I sacrifice great amounts of performance by not exploiting their features. And I ask you to do the same.