message: doc: install the documentation in the system
diff: @@ -35,3 +35,7 @@ add_custom_target(doc
  COMMAND ${CMAKE_COMMAND} -E copy_directory ${CMAKE_CURRENT_SOURCE_DIR}/img ${DOXY_WORKING_DIR}/html/img
  WORKING_DIRECTORY ${DOXY_WORKING_DIR}
  )
  +
  +############### Install the documentation in the system #######################
  +include(GNUInstallDirs)
  +install(DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/doxygen_doc/html/ DESTINATION ${CMAKE_INSTALL_DOCDIR})
  