anchor.diff:    # Generate the NixOS manual.
     manual = runCommand "nixos-manual"
       { inherit sources;
  -      buildInputs = [ libxml2 libxslt ];
  +      nativeBuildInputs = [ buildPackages.libxml2 buildPackages.libxslt ];
         meta.description = "The NixOS manual in HTML format";
         allowedReferences = ["out"];
       }
  
positive.code: 
    manual-combined = runCommand "nixos-manual-combined"
      { inherit sources;
        buildInputs = [ libxml2 libxslt ];
        meta.description = "The NixOS manual as plain docbook XML";
      }
      ''
  
negative.code:       echo "for hints about the offending path)."
        exit 1
      fi
      ${buildPackages.libxslt.bin}/bin/xsltproc \
        --stringparam revision '${revision}' \
        -o $out ${./options-to-docbook.xsl} $optionsXML
    '';
  