Investigate an encoding issue wrt path names

[wolfgangw]

Scenario is

• run with explicit path where package_dir contains e.g. umlauts is fine
• run with non-explicit path, which will potentially include more dirs than the run above, dies with a UTF-8 / ASCII encoding issue This happens after AM listing, at PKL path output.

[matmat]

Also see https://github.com/wolfgangw/backports/issues/74#issuecomment-1872568580