Better poll() compat and few cleanups.
Better poll() compat and few cleanups.

- Make resulting fd-count correct for poll().
- Don't allow any negative value as timeout, only -1.
- Clearer label names.

markokr/plproxy-dev,saaros/plproxy-dev,myrkraverk/plproxy,saaros/plproxy-dev,petere/plproxy-dev,markokr/plproxy-dev,nad2000/plproxy,mpihlak/plproxy-dev