anchor.diff:      "--enable-shared"
       "--with-threads"
       "--without-ensurepip"
  +    "--with-system-expat"
  +    "--with-system-ffi"
     ];
   
     preConfigure = ''
  
positive.code: { stdenv, fetchurl, fetchpatch
  , bzip2
  , gdbm
  , lzma
  , ncurses
  
negative.code:   sitePackages = "lib/${libPrefix}/site-packages";
  
    buildInputs = filter (p: p != null) [
      zlib bzip2 expat lzma libffi gdbm sqlite readline ncurses openssl ]
      ++ optionals x11Support [ tcl tk libX11 xproto ]
      ++ optionals stdenv.isDarwin [ CF configd ];
  
  