Fix an error when generating the Unuran dictionary on Windows
Fix an error when generating the Unuran dictionary on Windows

This fixes the following (potentially erroneous) error:
Error in <CloseStreamerInfoROOTFile>: Unique pointer unique_ptr<TUnuranBaseDist,default_delete<TUnuranBaseDist > > has zero data members.

olifre/root,olifre/root,karies/root,karies/root,root-mirror/root,root-mirror/root,olifre/root,olifre/root,olifre/root,root-mirror/root,olifre/root,olifre/root,karies/root,root-mirror/root,olifre/root,karies/root,olifre/root,root-mirror/root,karies/root,karies/root,root-mirror/root,karies/root,olifre/root,karies/root,karies/root,root-mirror/root,karies/root,root-mirror/root,olifre/root,root-mirror/root,root-mirror/root,karies/root,root-mirror/root