anchor.diff:  { stdenv, fetchurl, perl, gdb, autoconf, automake }:
   
  -stdenv.mkDerivation rec {
  +stdenv.mkDerivation (rec {
     name = "valgrind-3.6.1";
   
     src = fetchurl {
  
positive.code:     license = "GPLv2+";
  
      maintainers = [ stdenv.lib.maintainers.eelco ];
      
      platforms = stdenv.lib.platforms.linux ++ stdenv.lib.platforms.darwin;
    };
  }
  
negative.code:   buildInputs = stdenv.lib.optional (!stdenv.isDarwin) gdb;
  
    configureFlags =
      if (stdenv.system == "x86_64-linux" || stdenv.system == "x86_64-darwin")
      then [ "--enable-only64bit" ]
      else [];
  
    postInstall = ''
      for i in $out/lib/valgrind/*.supp; do
  