MACRO(USE_SLAM6D)
  FIND_PACKAGE(SLAM6D)
  IF ((NOT SLAM6D_FOUND) AND (${ARGC} LESS 1))
    USING_MESSAGE("Skipping because of missing SLAM6D")
    RETURN()
  ENDIF((NOT SLAM6D_FOUND) AND (${ARGC} LESS 1))
  IF(NOT SLAM6D_USED AND SLAM6D_FOUND)
    SET(SLAM6D_USED TRUE)
    INCLUDE_DIRECTORIES(SYSTEM ${SLAM6D_INCLUDE_DIR})
    SET(EXTRA_LIBS ${EXTRA_LIBS} ${SLAM6D_LIBRARIES})
  ENDIF()
ENDMACRO(USE_SLAM6D)