title: Does CMake support Python3?
body: <p>I am not able to build a Python wrapper module for my C library via CMake and Swig for Python3. Everything works fine for Python2.x but it looks like CMake cannot find Python3. I already looked around and tried a couple of things. </p>
  
  <p>For example, my <code>python</code> executable links to Python3, as I read CMake will find this version first.</p>
  
  <p>Please see here the SWIG part of the <code>CMakeLists.txt</code>:</p>
  
  <pre><code>FIND_PACKAGE(SWIG REQUIRED)
  INCLUDE(${SWIG_USE_FILE})
  
  FIND_PACKAGE(PythonInterp 3)
  FIND_PACKAGE(PythonLibs 3)
  
  FIND_PATH(PYTHON_INCLUDE_PATH Python.h
    /usr/include
    /usr/local/include)
  INCLUDE_DIRECTORIES(${PYTHON_INCLUDE_DIRS})
  
  INCLUDE_DIRECTORIES(${CMAKE_CURRENT_SOURCE_DIR})
  
  SET(CMAKE_SWIG_FLAGS "")
  
  SET_SOURCE_FILES_PROPERTIES(kissCT3.i PROPERTIES CPLUSPLUS ON)
  #SET_SOURCE_FILES_PROPERTIES(kissCT3.i PROPERTIES SWIG_FLAGS "-includeall -py3")
  
  SWIG_ADD_MODULE(kissCT3 python kissCT3.i)
  SWIG_LINK_LIBRARIES(kissCT3 libct2d matio kissfft ${PYTHON_LIBRARIES})
  </code></pre>
  
  <p>Unfortunately, the output after calling cmake shows that only python2.7 is found:</p>
  
  <pre><code>-- Found SWIG: /usr/bin/swig2.0 (found version "2.0.4")
  -- Found PythonInterp: /usr/bin/python2.7 (Required is at least version "3")
  -- Found PythonLibs: /usr/lib/libpython2.7.so (Required is at least version "3")
  -- Configuring done
  -- Generating done
  </code></pre>