Daniel Arndt

For the C++17 pull request, we are currently using - GCC 12.1.1 - clang 14.0.0 - clang 14.0.5 - GCC 11.2.0 - ICC 2021.6.0.20220226 - IntelLLVM 2022.1.0 - clang 11...

Also, what are we doing about `XL` and `PGI`? Do we drop support for `PGI` to only support `NVHPC`? Classic `XL` doesn't seem to have C++17 support at all (https://en.cppreference.com/w/cpp/compiler_support/17,...

- Ubuntu 18.04 LTS comes with `gcc-7.4.0`, `clang-6.0` - Ubuntu 20.04 LTS comes with `gcc-9.3.0`, `clang-10.0` - Ubuntu 22.04 LTS comes with `gcc-11.2.0`, `clang-14.0`

Problems in https://github.com/kokkos/kokkos/issues/3496 would also suggest to rather require cuda 11.2 than cuda 11.0.

In the `CMake` configuration, we check for compilers `GCC < 7`, `nvcc =13`, `clang < 13`, - `gcc==10.3.0`, `gcc >= 7.1.0`, `gcc < 5.3.0`, `gcc >= 9.1.0`, `gcc >= 6.1.0`,...

`CentOS 8 Stream` has `gcc-8.5` and `clang-14.0`.

Summit has gcc `7.5.0` but `gcc-9.1.0` is the default, the oldest llvm release is `10.0.1` which is also the default.

We should still discuss what to do with XL and PGI.

What's the point of adding this if it's entirely unused?

We should make sure that the behavior for finding `mdspan` as an external dependency is consistent with the discussion in https://github.com/kokkos/kokkos/pull/5053#discussion_r896846533 for `desul`.