As far as I understand the libindi dependency is optional in KStars, at least is marked as such in the CMakeLists.txt

I think since this commit KStars no longer builds without libindi:
https://cgit.kde.org/kstars.git/commit/?id=2f928fbf

So if what you want to do is keeping what is done in 2f928fbf for the lite version, but at the same time keeping KStars non-lite buildable without libindi, consider applying this patch.

If you want to do something else, feel free to reject this patch and push the correct solution.