anchor.diff:    '' + lib.optionalString revert ''
       ${patchutils}/bin/interdiff "$out" /dev/null > "$tmpfile"
       mv "$tmpfile" "$out"
  -  '' + (args.postFetch or "");
  +  '' + postFetch;
     meta.broken = excludes != [] && includes != [];
   } // builtins.removeAttrs args ["stripLen" "extraPrefix" "excludes" "includes" "revert" "postFetch"])
  
positive.code:   # 0.3.4 would change hashes: https://github.com/NixOS/nixpkgs/issues/25154
    patchutils = buildPackages.patchutils_0_3_3;
  in
  { stripLen ? 0, extraPrefix ? null, excludes ? [], includes ? [], revert ? false, ... }@args:
  
  fetchurl ({
    postFetch = ''
      tmpfile="$TMPDIR/patch"
      if [ ! -s "$out" ]; then
        echo "error: Fetched patch file '$out' is empty!" 1>&2
        exit 1
      fi
      "${patchutils}/bin/lsdiff" "$out" \
        | sort -u | sed -e 's/[*?]/\\&/g' \
        | xargs -I{} \
  
negative.code:       cat "$out" 1>&2
        exit 1
      fi
  
      ${patchutils}/bin/filterdiff \
        -p1 \
        ${builtins.toString (builtins.map (x: "-x ${lib.escapeShellArg x}") excludes)} \
  