anchor.diff: -{stdenv, fetchurl, qt4, bison, flex, eigen, boost, mesa, glew, opencsg, cgal
  -  , mpfr, gmp
  -  }:
  +{ stdenv, fetchurl, qt4, bison, flex, eigen, boost, mesa, glew, opencsg, cgal
  +, mpfr, gmp }:
   
   stdenv.mkDerivation rec {
  -  version = "2013.01";
  +  version = "2013.06";
     name = "openscad-${version}";
   
     src = fetchurl {
  
positive.code:     '';
      homepage = "http://openscad.org/";
      license = stdenv.lib.licenses.gpl2;
      platforms = with stdenv.lib.platforms;
        linux;
      maintainers = with stdenv.lib.maintainers; 
        [raskin bjornfor];
    };
  }
  
negative.code:     sha256 = "01r013l8zyfkgmqn05axh3rlfsjwd6j403w5ffl7nby4i2spiw1f";
    };
  
    buildInputs = [ qt4 bison flex eigen boost mesa glew opencsg cgal gmp mpfr ];
  
    configurePhase = ''
      export NIX_CFLAGS_COMPILE="$NIX_CFLAGS_COMPILE -I$(echo ${eigen}/include/eigen*) "
  