anchor.diff:  
     liquidwar = builderDefsPackage ../games/liquidwar {
       inherit (xlibs) xproto libX11 libXrender;
  -    inherit gmp guile mesa libjpeg libpng 
  +    inherit gmp guile mesa libjpeg libpng
         expat gettext perl
         SDL SDL_image SDL_mixer SDL_ttf
         curl sqlite
  
positive.code:   python = if getConfig ["python" "full"] false then pythonFull else pythonBase;
    python25 = if getConfig ["python" "full"] false then python25Full else python25Base;
    python26 = if getConfig ["python" "full"] false then python26Full else python26Base;
    pythonBase = python25Base;
    pythonFull = python25Full;
  
    python24 = import ../development/interpreters/python/2.4 {
      inherit fetchurl stdenv zlib bzip2;
  
negative.code: 
    content = builderDefsPackage ../applications/science/math/content {
      inherit mesa lesstif;
      inherit (xlibs) libX11 libXaw xproto libXt libSM libICE
        libXmu libXext libXcursor;
    };
  
  