downloading and unpacking binaries is not OS aware

When you run the makeproject.py script it will download binaries for that specific OS. However, if you later run the script in the same folder for a different OS (e.g. using WSL on Windows) it does not download the binary tgz files (since they already exist) and if you remove the tgz files it will download but not unpack the new files since the folder (e.g. QT632) already exists.

