message: Make CMAKE_INSTALL_PYTHONDIR persistent
  Fixes
diff: @@ -28,6 +28,9 @@ endif()
  string(REGEX REPLACE "^${PYTHON_PREFIX}/" ""
  CMAKE_INSTALL_PYTHONDIR "${PYTHON_SITE_PACKAGES}"
  )
  +set(CMAKE_INSTALL_PYTHONDIR "${CMAKE_INSTALL_PYTHONDIR}"
  + CACHE INTERNAL "" FORCE
  +)
  set_target_properties(adios2py PROPERTIES
  OUTPUT_NAME adios2
  LIBRARY_OUTPUT_DIRECTORY ${ADIOS2_BINARY_DIR}/${CMAKE_INSTALL_PYTHONDIR}
  