Warning : don't run the file setup.py as usual. It doesn't work. Simply because the following procedure is so easy that I didn't need to get the setup.py running.
For most Windows users it will be easiest to define an environment variable PYTHONPATH with the value C:\snapshots\lino\src (if your local copy is in c:\snapshots\lino).
On a Debian system you can create a file /usr/lib/site-python/sitecustomize.py containing the following:
import site site.addsitedir("/mnt/snapshots/lino/src")
Or you just set the PYTHONPATH environment variable to /mnt/snapshots/lino/src.