History of NagPerfDiag
The NagPerfDiag is a fork of PNP or PNP4Nagios. I have the need of special features which are never included in pnp4nagios. This was the starting point of NagPerfDiag. We will step forward and see if a merge is possible in the future.
Libraries and licences
NagPerfDiag (and PNP) using many libraries. This libraries are included in the source code. The authors and licences are now listed in the Authors file. I think, the licenses are not incompatible.