[CMake] SWIG interface file location

[James Bigler]

So I'm using SWIG to generate an interface file to python.

Can I get the interface file (myfile.py) to be built in the library path?

I need two things to run the interface.  The myfile.py file and the 
_myfile.so library with all the c code.  myfile.py gets placed in a 
subdirectory with myfilePYTHON_wrap.cxx.  It works out much better to 
have myfile.py be in the same directory as _myfile.so.

There doesn't seem to be any options to SWIG_ADD_MODULE that lets me 
specify the output directory.

Thanks,
James