* React on signal HUP resync and rewatch everything.
* Workaround the kernel watches limit by opening another inotify
  instance when needed.
* React on inotify OVERFLOW messages in resyncing everything, something might
  have been missed.
* Allow more complicated exclusion masks.
* Do not call rsync at all if a file was edited that falls under the exclusion
  mask (currently it is called, and rsync drops it.
* improve config.h.in generation