Got the Windows build fixed, with help from Yury. The toolchain had been
broken for months. We switched to using stack, which should make the
Windows build more reproducible and easy to manage.

Unfortunately, there was a link problem, and I had to disable some FFI code
that was needed to terminate processes on Windows. Until that gets fixed,
restarting and stopping the assistant won't work right on Windows.

Aaand: The EvilLinker is not needed any longer, so I was very happy to be
able to delete that hack. \o/
