Creating Symlink to Python Package Directory creates Broken Links when installing

[lkarstensen]

I'm using Sofa 21.06 with SofaPython3 on a machine with the following Configuration:

• Ubuntu 20.04
• Python 3.8 (Virtualenv)
• Cmake 3.16.3

When I am setting the "SP3_PYTHON_PACKAGES_LINK_DIRECTORY" Variable to the site-packages folder of my Virtualenv and set the "SP3_LINK_TO_USER_SITE" variable, only broken links are created in the "SP3_PYTHON_PACKAGES_LINK_DIRECTORY".

Therefore I cannot import Sofa in this Python Env or any other Python.

I already have a fix and will post it in a few Minutes.

[lkarstensen]

I still have things to learn when using issues and pull requests. But I created a Pull Request #164 with the fix.