Hydro on Yosemite catkin python-em

edit

Would anyone be able to suggest why I get this error and how I could debug it to try make Hydro from source? In that directory there is __init__py __init__.pyc locale tests. This is at step 2.1.3 here.

-- catkin 0.5.89
/usr/bin/python: can't find '__main__' module in '/Library/Python/2.7/site-packages/em'
CMake Error at cmake/safe_execute_process.cmake:11 (message):

  execute_process(/Users/kal04p/ros_catkin_ws/build_isolated/catkin/catkin_generated/env_cached.sh
  "/usr/bin/python" "/Library/Python/2.7/site-packages/em" "--raw-errors"
  "-F"
  "/Users/kal04p/ros_catkin_ws/build_isolated/catkin/catkin_generated/pkg.develspace.context.pc.py"
  "-o"
  "/Users/kal04p/ros_catkin_ws/devel_isolated/catkin/lib/pkgconfig/catkin.pc"
  "/Users/kal04p/ros_catkin_ws/src/catkin/cmake/em/pkg.pc.em") returned error
  code 1