The iOS APIs were reimplemented on Windows. The binaries are DLLs, with a few small EXEs as entry points, but the filenames make it obvious what's going on.
I did that for running iOS apps on Android; just recompile with another dll and the app works. It's not perfect but allows fast delivery for those clients who start with iOS and then don't really want to invest in Android (at that time) which, at least here, most of them.