Gwyddion uses the minizip library to work with zip-compressed files
such as .plux. Minizip is widely available because it comes with zlib,
a base compression library used just about everywhere in everything.
Yet, it is not a required nor recommended dependency in the debian
gwyddion package, which makes the feature of opening zipped packages
missing in debian.
Adding a simple dependency to libminizip-dev in the control file seems
to work. Tested on several versions of Ubuntu.