anchor.diff:      sw_vers = if stdenv.isDarwin then darwinSwVersUtility else null;
     };
   
  -  python26Full = python26Base.passthru.function {
  +  python26Full = lowPrio (python26Base.passthru.function {
       # FIXME: We lack ncurses support, needed, e.g., for `gpsd'.
       db4 = if getConfig ["python" "db4Support"] true then db4 else null;
       sqlite = if getConfig ["python" "sqliteSupport"] true then sqlite else null;
  
positive.code:     inherit fetchurl stdenv zlib bzip2 gdbm;
    };
  
    python25Full = python25Base.passthru.function {
      # FIXME: We lack ncurses support, needed, e.g., for `gpsd'.
      db4 = if getConfig ["python" "db4Support"] true then db4 else null;
      sqlite = if getConfig ["python" "sqliteSupport"] true then sqlite else null;
  
negative.code:     tcl = if getConfig ["python" "tkSupport"] true then tcl else null;
      libX11 = if getConfig ["python" "tkSupport"] true then xlibs.libX11 else null;
      xproto = if getConfig ["python" "tkSupport"] true then xlibs.xproto else null;
    });
  
    python26Base = composedArgsAndFun (import ../development/interpreters/python/2.6) {
      inherit fetchurl stdenv zlib bzip2 gdbm;
  