anchor.diff:      platforms = stdenv.lib.platforms.all;
       maintainers = [ stdenv.lib.maintainers.simons ];
     };
  -} // (if stdenv.isDarwin then { NIX_CFLAGS_COMPILE = "-msse2" ; patches = [./search-path.patch]; } else {} ) )
  +}
  
positive.code:   '';
  
    passthru = {
      inherit zlibSupport;
      sqliteSupport = sqlite != null;
      db4Support = db4 != null;
      readlineSupport = readline != null;
  
negative.code: { stdenv, fetchurl
  , zlib
  , bzip2
  , gdbm
  , sqlite
  , db4
  , ncurses
  , readline
  , openssl
  , tcl, tk
  , libX11, xproto
  , arch ? null, sw_vers ? null
  }:
  
  assert stdenv.isDarwin -> arch != null;
  assert stdenv.isDarwin -> sw_vers != null;
  assert readline != null -> ncurses != null;
  
  with stdenv.lib;
  
  let
    majorVersion = "3.1";
    version = "${majorVersion}.3";
  
    buildInputs = filter (p: p != null) [
      zlib bzip2 gdbm sqlite db4 readline ncurses openssl tcl tk libX11 xproto arch sw_vers
    ];
  in
  stdenv.mkDerivation {
    name = "python3-${version}";
    inherit majorVersion version;
  
  