anchor.diff:  rec {
     src = fetchurl {
       url = "http://prdownloads.sourceforge.net/sbcl/sbcl-${version}-source.tar.bz2";
  -    sha256 = "0cs9671jgmn50835m8ccssmq86ssj3pvpd9cjkkq5c3ggm1zddnq";
  +    sha256 = "1bdsn4rnrz289068f1bdnxyijs4r02if4p87fv726glp5wm20q1z";
     };
   
     inherit buildInputs;
  
positive.code: let 
    fetchurl = a.fetchurl;
  
    version = a.lib.attrByPath ["version"] "1.0.30" a; 
    buildInputs = with a; [
      clisp makeWrapper
    ];
  
negative.code:   };
  }
  
  
  