Add support for the TBB allocator on windows.

The heap on windows is single threaded causing it to lag behind linux in performance in allocation heavy multithreaded scenarios, BVH building is a prime example.

See https://developer.blender.org/D6218 for benchmark results

for testing with the allocator enabled/disabled you can set the environment variable TBB_MALLOC_DISABLE_REPLACEMENT=1 to disable the TBB allocator.

Reviewed By: @sergey

Differential Revision: https://developer.blender.org/D6218

build_files/cmake/platform/platform_win32.cmake

@@ -573,6 +573,9 @@ if(WITH_TBB)
   set(TBB_LIBRARIES optimized ${LIBDIR}/tbb/lib/tbb.lib debug ${LIBDIR}/tbb/lib/tbb_debug.lib)
   set(TBB_INCLUDE_DIR ${LIBDIR}/tbb/include)
   set(TBB_INCLUDE_DIRS ${TBB_INCLUDE_DIR})
+  if(WITH_TBB_MALLOC_PROXY)
+    add_definitions(-DWITH_TBB_MALLOC)
+  endif()
 else()
   if(WITH_OPENIMAGEDENOISE)
     message(STATUS "TBB disabled, also disabling OpenImageDenoise")