Adapt to Flatpak-from-RPM build
    
    (see <https://docs.fedoraproject.org/en-US/flatpak/>).  For one, various paths
    need to be configured explicitly, as LO's configure would fall back to hardcoded
    /usr paths instead of the /app paths needed here.  For another, it is unclear to
    me why those three __pycache__ files are not generated, but just not asking to
    include them should be harmless.