message: Fix version check for TBB
diff: ## limitations under the License. ##
  ## ======================================================================== ##
  -SET(TBB_MAJOR_VERSION_REQUIRED "3.0")
  +SET(TBB_VERSION_REQUIRED "3.0")
  IF (NOT TBB_ROOT)
  SET(TBB_ROOT $ENV{TBB_ROOT})
  @@ -108,7 +108,7 @@ ENDIF()
  SET(TBB_ROOT_LAST ${TBB_ROOT} CACHE INTERNAL "Last value of TBB_ROOT to detect changes")
  SET(TBB_ERROR_MESSAGE
  - "Threading Building Blocks (TBB) with minimum version ${TBB_MAJOR_VERSION_REQUIRED}.0 not found.
  + "Threading Building Blocks (TBB) with minimum version ${TBB_VERSION_REQUIRED} not found.
  OSPRay uses TBB as default tasking system. Please make sure you have the TBB headers installed as well (the package is typically named 'libtbb-dev' or 'tbb-devel') and/or hint the location of TBB in TBB_ROOT.
  Alternatively, you can try to use OpenMP as tasking system by setting OSPRAY_TASKING_SYSTEM=OpenMP")
  @@ -128,7 +128,7 @@ IF (TBB_INCLUDE_DIR)
  STRING(REGEX MATCH "#define TBB_VERSION_MINOR ([0-9]+)" DUMMY "${TBB_STDDEF_H}")
  SET(TBB_VERSION "${TBB_VERSION_MAJOR}.${CMAKE_MATCH_1}")
  - IF (TBB_VERSION_MAJOR VERSION_LESS TBB_VERSION_REQUIRED)
  + IF (TBB_VERSION VERSION_LESS TBB_VERSION_REQUIRED)
  MESSAGE(FATAL_ERROR ${TBB_ERROR_MESSAGE})
  ENDIF()
  