anchor.diff:        '';
       };
   
  +  os-switch = pkgs.writeScript "tttool-os-switch.sh" ''
  +    #!/bin/bash
  +    case "$OSTYPE" in
  +      linux*)   exec "$(dirname "$0")/linux/tttool" "$@" ;;
  +      darwin*)  exec "$(dirname "$0")/osx/tttool" "$@" ;;
  +      msys*)    echo "$(dirname "$0")/tttool.exe" "$@" ;;
  +      cygwin*)  echo "$(dirname "$0")/tttool.exe" "$@" ;;
  +      *)        echo "unsupported operating system $OSTYPE" ;;
  +    esac
  +  '';
  +
     release = pkgs.stdenv.mkDerivation {
       name = "tttool-release";
   
  
positive.code: 
        mkdir -p $out/
        cp -vsr ${static-files}/* $out
        cp -vs ${static-exe}/bin/tttool $out/
        cp -vs ${windows-exe}/bin/tttool.exe $out/
        mkdir -p $out/contrib
        cp -vsr ${contrib}/* $out/contrib/
        cp -vsr ${book}/* $out
      '';
  
negative.code:     builder = pkgs.writeScript "zip-tttool-release.sh" ''
        source ${pkgs.stdenv}/setup
  
        mkdir -p $out/bin/osx
        cp ${osx-exe}/bin/tttool $out/bin/osx
        chmod u+w $out/bin/osx/tttool
  