Currently the stable release source code is distributed in a 7z archive,
which does not support Linux permissions.  In order to compile it, and create
a source tarball, extract the archive, run

chmod -R 777 <extracted-source-directory>

and then recompress the source into an approved Debian tarball format.

Make sure to add a "~repack" to the versioning and the orig tarball to label it
as repacked.  OBS builds require this be a ".repack".
