[vtkusers] build failure in hybrid

[Brad King]

> I can't seem to build vtk.  I am using gentoo linux with lam-mpi.  My
> CMakeCache.txt is included beneath the warnings.  The error I get is:
[snip]
> Building executable /home/hal9000/VTK-4.2.2/bin/pvtk...
> /home/hal9000/VTK-4.2.2/bin/libvtkHybridTCL.so: undefined reference to
> `vtkPushPipeline::New()'

I think this has been fixed in VTK 4.2.3.

-Brad