I have finally resolved the situation that nant quickClean did not delete the files generated by nant generateORM.
I have also updated the behaviour of nant uncrustify, to only exclude files that have -generated. in their filename.
see also tracker.openpetra.org/view.php?id=2416
One thing that is important for all developers:
When you merge from trunk, or checkout from trunk into an existing working tree: Please manually delete the files in shared/lib/data and server/lib/data, since they are not removed by a quickClean. This needs to be done only once.
The Jenkins Server might need a workspace clean up as well.