Dear Helmut Grohne, thank you so much for providing a patch to fix this bug. I am trying to adopt Eterm package, so I uploaded a new version of Eterm package to mentors including your patch (and other fixes). I have tested the new package in my system and it install/uninstall flawlessly. The package is available at:
https://mentors.debian.net/package/eterm As Debian is in freeze period I will not include more modifications until Buster is released. Sincerely, Jose A. P.S.: Eterm's Homepage is down a this moment. I have contacted with upstream and asked them to fix it.