message: provide a way to turn off compiling the tutorial
  simplifies packaging a tiny bit for library consumers.
diff: @@ -492,12 +492,17 @@ IF(OSPRAY_BUILD_ISPC_DEVICE)
  )
  ENDIF()
  -# build ospTutorial, for testing
  +OPTION(OSPRAY_ENABLE_TUTORIAL
  + "Build the tutorial executable" ON)
  +MARK_AS_ADVANCED(OSPRAY_ENABLE_TUTORIAL)
  +IF(OSPRAY_ENABLE_TUTORIAL)
  + # build ospTutorial, for demonstration and API testing
  ADD_EXECUTABLE(ospTutorial ../apps/ospTutorial.c)
  TARGET_LINK_LIBRARIES(ospTutorial ospray)
  # C++ version
  ADD_EXECUTABLE(ospTutorialCpp ../apps/ospTutorial.cpp)
  TARGET_LINK_LIBRARIES(ospTutorialCpp ospray)
  +ENDIF()
  ##############################################################
  # Configure find_package files
  