[vtkusers] Problems with turning tcl bindings on in cmake step

[Alark Joshi]

Hello,

I have downloaded and built vtk a few times before. But in the last couple 
of days I've observed that if I set "VTK_WRAP_TCL" to be ON, it gives me a 
"empty include directories" error. The tcl_include and tk_include paths are 
fine and I've observed it on 2 different machines now. Any thoughts?

Regards,

Alark