[vtkusers] Build with MPEG2

[Gib Bogle]

Hi,

I tried to follow the instructions for building VTK with the MPEG2 library. 
First I built the library.  Using cmake-gui.exe on Windows XP, I can set the 
cmake variables vtkMPEG2Encode_INCLUDE_PATH and vtkMPEG2Encode_LIBRARIES and 
they stick after I click "configure", but although I can add the variable 
VTK_USE_MPEG2_ENCODER, it disappears from the list after the "configure" step. 
Not surprisingly, the .vcproj file created doesn't include vtkMPEG2decoder.cxx 
(in vtkIO, which is where I expect to see it).

Am I doing something wrong?

Gib