anchor.diff:    postFixup = ''
       # Get rid of retained dependencies on -dev packages, and remove
       # some $TMPDIR references to improve binary reproducibility.
  -    for i in $out/lib//python${majorVersion}/_sysconfigdata.py $out/lib/python${majorVersion}/config-${majorVersion}m/Makefile; do
  +    for i in $out/lib/python${majorVersion}/_sysconfigdata.py $out/lib/python${majorVersion}/config-${majorVersion}m/Makefile; do
         sed -i $i -e "s|-I/nix/store/[^ ']*||g" -e "s|-L/nix/store/[^ ']*||g" -e "s|$TMPDIR|/no-such-path|g"
       done
   
       # FIXME: should regenerate this.
       rm $out/lib/python${majorVersion}/__pycache__/_sysconfigdata.cpython*
  +
  +    # tkinter goes in a separate output
  +    mkdir -p $tkinter/${sitePackages}
  +    mv $out/lib/${libPrefix}/lib-dynload/_tkinter* $tkinter/${sitePackages}/
     '';
   
  +  outputs = ["out" "tkinter"];
  +
     passthru = rec {
  -    inherit libPrefix;
  +    inherit libPrefix sitePackages;
       zlibSupport = zlib != null;
       sqliteSupport = sqlite != null;
       dbSupport = false;
  
positive.code:   pythonVersion = majorVersion;
    version = "${majorVersion}.${minorVersion}${minorVersionSuffix}";
    libPrefix = "python${majorVersion}";
  
    buildInputs = filter (p: p != null) [
      zlib
  
negative.code:     isPy3 = true;
      isPy35 = true;
      is_py3k = true;  # deprecated
      interpreter = "${self}/bin/${executable}";
    };
  
  