[CMake] Java Native Interface Support

[Brad King]

Oh K wrote:
> I am considering using cmake for my recent project which requires the
> integration between java and its native implementation.
> 
> I found VTK also have the similar requirement and made some extensions
> to cmake to wrap C API for Java interface and generate dependencies
> between them.  I think it would be nice if cmake has them as its
> common features.

The VTK_WRAP_* commands were put in CMake before the CMake language 
itself was powerful enough to implement the commands as macros in VTK's 
source.  They are no longer used and are present only for compatibility 
with older VTK source trees.  Project-independent wrapping is not easy 
and is outside the scope of CMake itself.  However, CMake does provide 
custom command support to allow projects to have their own wrapper 
generation rules.  This support is now utilized by the VTK_WRAP_*3 
macros in VTK.  There is also support for SWIG.

-Brad