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.
    
    Forward-ported from f31, combined cherry-pick of:
    * bfd5f11376b8c70e5280f6aa307390e0b6246654 "Adapt to Flatpak-from-RPM build"
    * 385664d08b0e1fa3cde3ea3fc7fa20279a109280 "Hack libreoffice-multiliblauncher.sh
      for flatpak"
    * decfe42573aed89586a937a05e5a653b0847afc0 "Fix Flatpak-from-RPM build"
    * 093c4953a62c12cf0335025c6a9aa9bad0b86cf1 "Fix Flatpak-from-RPM build"
    * 3d51346db2cf92f63653a76cd534d0a3afe4b0d2 "Fix Flatpak-from-RPM build"
    * a9e4c56f3282ce801570c890e4b1dee221f2adc2 "Fix flatpak
      --with-commons-logging-jar"