Add FETCH_TBB/FETCH_ONEDPL changes from BabelStream

CMakeLists.txt

@@ -70,16 +70,20 @@ option(USE_TBB "Enable oneTBB library for *supported* models. Enabling this on m
  don't explicitly link against TBB is a no-op, see description of your selected
  model on how this is used." OFF)
 
-if (USE_TBB)
+option(FETCH_TBB "Fetch (download) the oneTBB library for *supported* models. This uses CMake's
+ FetchContent feature. Specify version by setting FETCH_TBB_VERSION" OFF)
+set(FETCH_TBB_VERSION "v2021.10.0" CACHE STRING "Specify version of oneTBB to use if FETCH_TBB is ON")
+
+if (FETCH_TBB)
  FetchContent_Declare(
  TBB
  GIT_REPOSITORY https://github.com/oneapi-src/oneTBB.git
- GIT_TAG faaf43c4ab22cb4b4267d65d5e218fa58800eea8
+ GIT_TAG "${FETCH_TBB_VERSION}"
  )
  # Don't fail builds on waring (TBB has -Wall while not being free of warnings from unused symbols...)
  set(CMAKE_POLICY_DEFAULT_CMP0077 NEW)
  set(TBB_STRICT OFF)
- # Not using FetchContent_MakeAvailable because we need EXCLUDE_FROM_ALL
+ # Not using FetchContent_MakeAvailable (CMake>= 3.14) because we need EXCLUDE_FROM_ALL
  FetchContent_GetProperties(TBB)
  if (NOT TBB_POPULATED)
  FetchContent_Populate(TBB)
@@ -91,11 +95,15 @@ option(USE_ONEDPL "Enable oneDPL library for *supported* models. Enabling this o
  don't explicitly link against DPL is a no-op, see description of your selected
  model on how this is used." OFF)
 
-if (USE_ONEDPL)
+option(FETCH_ONEDPL "Fetch (download) the oneDPL library for *supported* models. This uses CMake's
+ FetchContent feature. Specify version by setting FETCH_ONEDPL_VERSION" OFF)
+set(FETCH_ONEDPL_VERSION "oneDPL-2022.2.0-rc1" CACHE STRING "Specify version of oneTBB to use if FETCH_ONEDPL is ON")
+
+if (FETCH_ONEDPL)
  FetchContent_Declare(
  oneDPL
  GIT_REPOSITORY https://github.com/oneapi-src/oneDPL.git
- GIT_TAG oneDPL-2022.2.0-rc1
+ GIT_TAG "${FETCH_ONEDPL_VERSION}"
  )
  string(TOLOWER ${USE_ONEDPL} ONEDPL_BACKEND)
  # XXX oneDPL looks for omp instead of openmp, which mismatches(!) with ONEDPL_PAR_BACKEND if using find_package