anchor.diff:  , x86Only ? false
   }:
   
  -let n = "qemu-1.5.2"; in
  +let n = "qemu-1.7.0"; in
   
   stdenv.mkDerivation rec {
     name = n + (if x86Only then "-x86-only" else "");
   
     src = fetchurl {
       url = "http://wiki.qemu.org/download/${n}.tar.bz2";
  -    sha256 = "0l52jwlxmwp9g3jpq0g7ix9dq4qgh46nd2h58lh47f0a35yi8qgn";
  +    sha256 = "050kq9mz8c2jcshm7nn7dldypsk8jr590ybnlw2wc51dbyl37wri";
     };
   
     buildInputs =
       [ python zlib pkgconfig glib ncurses perl pixman attr libcap
  -      vde2 alsaLib texinfo libuuid makeWrapper
  +      vde2 alsaLib texinfo libuuid flex bison makeWrapper
       ]
       ++ stdenv.lib.optionals sdlSupport [ SDL ]
       ++ stdenv.lib.optionals vncSupport [ libjpeg libpng ]
  
positive.code:       fi
      '';
  
    meta = {
      homepage = http://www.qemu.org/;
      description = "A generic and open source machine emulator and virtualizer";
      license = "GPLv2+";
      maintainers = with stdenv.lib.maintainers; [ viric shlevy eelco ];
      platforms = stdenv.lib.platforms.linux;
    };
  }
  
negative.code: { stdenv, fetchurl, python, zlib, pkgconfig, glib, ncurses, perl, pixman
  , attr, libcap, vde2, alsaLib, texinfo, libuuid, flex, bison
  , makeWrapper
  , sdlSupport ? true, SDL
  , vncSupport ? true, libjpeg, libpng
  