It looks like saga changed the way how their tarball is made
as a result, files are now stored in the tarball as:
/saga-8.0.1/saga-gis/xxx
rather than /saga-gis/xxx
I adjusted the paths in debian/copyright to make sure paths are stripped now,
But I wonder if there is an elegant way to repackage without the parent dir. I remember using get-orig-source target in d/rules, but as this is now deprecated.