I've squashed the non compiling commits. They should all compile now. :)

Thanks! Unfortunately the history is still a mess because the engine hasn't been rebased continuously on top of master which results in many commits still failing to compile (among other things this is especially a pain when bisecting).

I have now tried cleaning this up by cherry-picking all non-merge commits touching engines/illusions/ since commit
3d91c85 (oldest commit in your PR) into a new branch on top of master. I fixed the commit messages not following our guidelines and then interactively rebased and stepped through every single commit making sure all necessary changes to make every commit compile propagate properly.

Something along the lines of (this is from memory):

$ git checkout yumv422/illusions
$ git rev-list 3d91c85^..HEAD -- engines/illusions >/tmp/illusions.commits
$ git checkout master
$ git checkout -b bonki-illusions-cleanup
$ xargs -n 1 git cherry-pick < <(tac /tmp/illusions.commits)
$ git rebase -i 3d91c85^
(s#pick#edit#g)
$ while make -j6 && git add . && git commit --amend --no-edit && git rebase --continue; do :; done
(fix stuff)
$ git diff yuv422/illusions -- engines/illusions
(no diff, yay)

This resides in bonki/bonki-illusions-cleanup.

I hope someone can confirm that I didn't do anything silly and the result is as expected.

@bonki
Your branch looks good to me. :)

So the next step is to merge bonki/bonki-illusions-cleanup into master?

I'm happy to merge, especially since @johndoe123's recent changes have been merged since and nobody has objected in quite a while. OK @sev-?

Merged, and added @yuv422 to the team.