The code here is sort of self-explanatory, but since I split it up over
several patches I'll provide a quick explanation. The basic principle is
that we can create an eventfd descriptor for any synchronizable handle, and
signal it on the server side whenever a wakeup would be triggered. This means
not only that we can wait simultaneously on esync primitives and on other
primitives, but that we can do it all in "user-mode", i.e. without having to
make a server call.

With this patch we break waiting on svcctl.exe.