anchor.diff:         export NIX_CFLAGS_COMPILE="$NIX_CFLAGS_COMPILE -msse2"
          export MACOSX_DEPLOYMENT_TARGET=10.6
        ''}
  -
  -    configureFlagsArray=( --enable-shared --with-threads
  -                          CPPFLAGS="${concatStringsSep " " (map (p: "-I${getDev p}/include") buildInputs)}"
  -                          LDFLAGS="${concatStringsSep " " (map (p: "-L${getLib p}/lib") buildInputs)}"
  -                          LIBS="${optionalString (!stdenv.isDarwin) "-lcrypt"} ${optionalString (ncurses != null) "-lncurses"}"
  -                        )
     '';
   
     setupHook = ./setup-hook.sh;
  
positive.code: 
    NIX_LDFLAGS = optionalString stdenv.isLinux "-lgcc_s";
  
    prePatch = optionalString stdenv.isDarwin ''
      substituteInPlace configure --replace '`/usr/bin/arch`' '"i386"'
      substituteInPlace configure --replace '-Wl,-stack_size,1000000' ' '
    '';
  
    postPatch = optionalString (x11Support && (tix != null)) ''
      substituteInPlace "Lib/tkinter/tix.py" --replace "os.environ.get('TIX_LIBRARY')" "os.environ.get('TIX_LIBRARY') or '${tix}/lib'"
    ''
      # Avoid picking up getentropy() from glibc >= 2.25, as that would break
      # on older kernels.  http://bugs.python.org/issue29157
      + optionalString stdenv.isLinux
        ''
          substituteInPlace Python/random.c --replace 'defined(HAVE_GETENTROPY)' '0'
          cat Python/random.c
        '';
  
    preConfigure = ''
      for i in /usr /sw /opt /pkg; do	# improve purity
  
negative.code:     ln -s "$out/bin/python3" "$out/bin/python"
      ln -s "$out/bin/python3-config" "$out/bin/python-config"
      ln -s "$out/lib/pkgconfig/python3.pc" "$out/lib/pkgconfig/python.pc"
  
      # Determinism: rebuild all bytecode
      # We exclude lib2to3 because that's Python 2 code which fails
      # We rebuild three times, once for each optimization level
      find $out -name "*.py" | $out/bin/python -m compileall -q -f -x "lib2to3" -i -
      find $out -name "*.py" | $out/bin/python -O -m compileall -q -f -x "lib2to3" -i -
      find $out -name "*.py" | $out/bin/python -OO -m compileall -q -f -x "lib2to3" -i -
    '';
  
    postFixup = ''
  