vtk-config: handle non-VTK components
Some projects set themselves up to "be" VTK even when they are not. In order to prevent VTK from having to guarantee compatibility for the mechanisms that VTK uses internally to these projects, prevent them from being falsely handled as VTK components.
There are a number of reasons non-VTK projects should not rely on VTK to provide their own package. Of note:
- it only works for VTK modules (targets managed with
vtkModule.cmake
APIs) - consistent wrapping patterns are not provided
- Java-wrapped modules cannot join
vtk.jar
- Python-wrapped will not be part of
vtkmodules.all
- Java-wrapped modules cannot join
- it ends up being a compatibility hazard and I want to keep what VTK provides to a known set instead of having projects end up relying on behaviors that are not intended to be guaranteed
- other projects should manage their own CMake interface instead of being at the mercy of VTK