> They wanted to check if the version is 5 or 6, and then do different things depending on that. Also there is a problem if you have two versions installed, how to choose the newest version available (between 5.8 and 6.0); anyway that is not implement there, but you can force it setting the VTK_DIR variable (I believe).

I don't see how any of that invalidates my suggestion.

> Anyway, the second commit is not the actual problem, the first one is the one which actually solves the problem I had with the compilation.

Then perhaps you shouldn't have included it in the pull request.