besides updating the version/src sha, upstream switched to GTK3, as can
be seen in the release notes [0]. This apparently requires the ocaml
cairo2 bindings an zlib. I also used wrapGAppsHook to supply the schemas
from gsettings-desktop-schemas. Screenshot: https://i.imgur.com/CrPvLgQ.png
I can not test the Icon creation since I am not using a desktop, @viric
please check. Maybe this is also done by wrapGAppsHook..
[0] https://github.com/bcpierce00/unison/releases/tag/v2.53.0