message: Future-proof clang compile CI.
  Automatically test for the latest supported version installed
  on the machine and use that to set CXX and CC environment
  variables.
diff: @@ -19,8 +19,16 @@ set -e
  source ./.github/settings.sh
  if [[ "${MODE}" == "compile-clang" ]]; then
  - export CXX=clang++-10
  - export CC=clang-10
  + # clang versions supported. Starting with 13, we
  + # get some warnings in absl, so let's not go beyond
  + # 12 for now.
  + for version in 12 11 10 ; do
  + if command -v clang++-${version}; then
  + export CXX=clang++-${version}
  + export CC=clang-${version}
  + break
  + fi
  + done
  fi
  # Make sure we don't have cc_library rules that use exceptions but do not
  