anchor.diff:  
       # Run the library tests as they don't have external dependencies
       doCheck = true;
  -    checkInputs = lib.optionals stdenv.isDarwin [ getconf ];
  +    checkInputs = [ bash fish zsh ] ++ (lib.optionals stdenv.isDarwin [ getconf ]);
       checkPhase = ''
         runHook preCheck
         # test list repeats suites. Unique them
  
positive.code: , coreutils
  , getconf
  , less
  # batgrep
  , ripgrep
  # prettybat
  
negative.code:       while read -r action arg _; do
          [[ "$action" == "test_suite" && "$arg" == lib_* ]] &&
          test_suites+=(["$arg"]=1)
        done <<<"$(./test.sh --compiled --list --porcelain)"
        (( ''${#test_suites[@]} != 0 )) || {
          echo "Couldn't find any library test suites"
          exit 1
        }
        ./test.sh --compiled $(printf -- "--suite %q\n" "''${!test_suites[@]}")
        runHook postCheck
      '';
  
  