message: Only enable example 13 if CEGUI is enabled
diff: @@ -9,7 +9,9 @@ add_subdirectory(09.ColorSpaceTest EXCLUDE_FROM_ALL)
  add_subdirectory(10.AllocPerfTest EXCLUDE_FROM_ALL)
  add_subdirectory(11.RayCastCollision EXCLUDE_FROM_ALL)
  add_subdirectory(12.Splines EXCLUDE_FROM_ALL)
  +if (IRR_BUILD_CEGUI)
  add_subdirectory(13.BRDF_Explorer EXCLUDE_FROM_ALL)
  +endif()
  add_subdirectory(14.MSAA EXCLUDE_FROM_ALL)
  add_subdirectory(15.LayeredCubeMapShadows EXCLUDE_FROM_ALL)
  add_subdirectory(16.OrderIndependentTransparencyZoo EXCLUDE_FROM_ALL)
  