[vtk-developers] Why do we need the VTK_WRAP_HIERARCHY_EXE variable.

[Utkarsh Ayachit]

In vtkWrapHierarchy.cmake, why is the VTK_WRAP_HIERARCHY_EXE variable
needed/used? Why can't we simply refer to the target
vtkWrapHieararchy? Since the target is exported in VTKTarget.cmake,
it's makes it easier for external projects depending on CMake to use
the vtkWrapHierarchy.cmake as needed.

Utkarsh