message: Fix in Python3 if sphinx is not installed
diff: @@ -122,8 +122,12 @@ if(PYTHONINTERP_FOUND AND CYTHON_FOUND)
  # Documentation generation is available through sphinx
  find_program( SPHINX_PATH sphinx-build )
  elseif(PYTHON_VERSION_MAJOR EQUAL 3)
  + execute_process(COMMAND ${PYTHON_EXECUTABLE} -c "from sphinx import main"
  + RESULT_VARIABLE SPHINX_MODULE_IS_INSTALLED)
  + if(SPHINX_MODULE_IS_INSTALLED)
  # No sphinx-build in Pyton3, just hack it
  set(SPHINX_PATH "${CMAKE_CURRENT_BINARY_DIR}/${GUDHI_CYTHON_PATH}/doc/python3-sphinx-build")
  + endif(SPHINX_MODULE_IS_INSTALLED)
  else()
  message(FATAL_ERROR "ERROR: Try to compile the Cython interface. Python version ${PYTHON_VERSION_STRING} is not valid.")
  endif(PYTHON_VERSION_MAJOR EQUAL 2)
  