anchor.diff:    };
   
     ffi = attrs: {
  -  nativeBuildInputs = [ pkgconfig ];
  +    nativeBuildInputs = [ pkgconfig ];
       buildInputs = [ libffi ];
     };
   
  
positive.code:     '';
    };
  
    do_sqlite3 = attrs: {
      buildInputs = [ sqlite ];
    };
  
negative.code:   xapian-ruby = attrs: {
      # use the system xapian
      dontBuild = false;
      nativeBuildInputs = [ pkgconfig ];
      buildInputs = [ xapian_1_2_22 zlib ];
      postPatch = ''
        cp ${./xapian-Rakefile} Rakefile
  