At some point a patch accidentally removed
```
done
break
```
from an if then/while loop in `startkde`.
Which still breaks, but not the way we want...
plasma-workspace-5.16.5/bin/startkde: line 403: syntax error near unexpected token `fi'
plasma-workspace-5.16.5/bin/startkde: line 403: ` fi'
- Patch wasn't applied entirely because of a line number error in a diff header (see L84)
- Rewrite of the patch file using git to fix other inconsistencies (git format-patch)
- Remove xdg-desktop-menu-dummy.menu kbuildsycoca5. Not sure why we
need it but it is a pretty big failure if it exists.
See issue #56176.
- plasma: clear ksycoca cache before building
This is needed to pick up on software removed since the last cache
update. Otherwise it hangs around as zombies forever (or until the
cache is cleared).
- Add the above + the icon cache cleanup to plasmaSetup
This will be run for the logged in user on each nixos-rebuild.
Unfortunately this only works if you are managing software through
nixos-rebuild (nix-env users need to run this manually, otherwise
log out and log back in).
