std::iterator is deprecated in c++17. We can just declare the required types for iterator traits directly without the helper. Change-Id: I789e2c2b13e56cc391527686109df8b779474d09 Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/66351 Reviewed-by: Gabe Black <gabeblack@google.com> Maintainer: Gabe Black <gabeblack@google.com> Tested-by: kokoro <noreply+kokoro@google.com>