message: Print pybind11 version, protect test
diff: @@ -32,6 +32,10 @@ function( add_gudhi_debug_info DEBUG_INFO )
  endfunction( add_gudhi_debug_info )
  if(PYTHONINTERP_FOUND)
  + if(PYBIND11_FOUND)
  + add_gudhi_debug_info("Pybind11 version ${PYBIND11_VERSION}")
  + set(GUDHI_PYTHON_MODULES_EXTRA "${GUDHI_PYTHON_MODULES_EXTRA}'hera', ")
  + endif()
  if(CYTHON_FOUND)
  set(GUDHI_PYTHON_MODULES "${GUDHI_PYTHON_MODULES}'off_reader', ")
  set(GUDHI_PYTHON_MODULES "${GUDHI_PYTHON_MODULES}'simplex_tree', ")
  @@ -391,9 +395,9 @@ endif(CGAL_FOUND)
  add_gudhi_py_test(test_reader_utils)
  # Wasserstein
  - if(OT_FOUND)
  + if(OT_FOUND AND PYBIND11_FOUND)
  add_gudhi_py_test(test_wasserstein_distance)
  - endif(OT_FOUND)
  + endif()
  # Representations
  if(SKLEARN_FOUND AND MATPLOTLIB_FOUND)
  