Created attachment 50116 [details] [review]
Don't build any of the reload-pipe code on non-Unix

In commit ab7b3f9, Ralf notes that handle_reload_watch() is (in principle) cross-platform. However, there's no way to trigger it on Windows, because nothing ever writes to the pipe (the only way to reload on Windows is ReloadConfig(), which just does the reload there and then, without messing about with Unix signals). It seems cleaner to make the entire pipe-to-self trick Unix-specific instead.