anchor.diff:      inherit fetchurl stdenv;
     };
   
  -  coreutils = useFromStdenv (stdenv ? coreutils) stdenv.coreutils
  +  coreutils = useFromStdenv "coreutils"
       ((if stdenv ? isDietLibC
         then import ../tools/misc/coreutils-5
         else import ../tools/misc/coreutils)
  
positive.code:     inherit (xlibs) libXext;
    };
  
    gnugrep = useFromStdenv (stdenv ? gnugrep) stdenv.gnugrep
      (import ../tools/text/gnugrep {
        inherit fetchurl stdenv pcre;
      });
  
    gnupatch = useFromStdenv (stdenv ? patch) stdenv.patch (import ../tools/text/gnupatch {
      inherit fetchurl stdenv;
    });
  
  
negative.code:   # inside the set for derivations.
    recurseIntoAttrs = attrs: attrs // {recurseForDerivations = true;};
  
    useFromStdenv = it : alternative : if (builtins.hasAttr it stdenv) then
      (builtins.getAttr it stdenv) else alternative;
  
    lib = library;
  
  