anchor.diff:  { stdenv, fetchurl, fetchgit, which, file, perl, curl, python27, makeWrapper
  -, tzdata, git, valgrind
  +, tzdata, git, valgrind, procps, coreutils
   }:
   
   assert stdenv.gcc.gcc != null;
  
positive.code: 
    src = fetchgit {
      url = https://github.com/rust-lang/rust;
      rev = "3a325c666d2cb7e297bf3057ff2442f96a79428b";
      sha256 = "0a0byglfaf0wfsnlm53vng1gqkkz4i29zphdwqg93v26mciqqc61";
    };
  
    # We need rust to build rust. If we don't provide it, configure will try to download it.
  
negative.code:       --subst-var-by "ccPath" "${stdenv.gcc}/bin/cc"
      substituteInPlace src/librustc_back/archive.rs \
        --subst-var-by "arPath" "${stdenv.gcc.binutils}/bin/ar"
  
      substituteInPlace src/rust-installer/gen-install-script.sh \
        --replace /bin/echo "${coreutils}/bin/echo"
    '';
  
    buildInputs = [ which file perl curl python27 makeWrapper git valgrind procps ];
  
    enableParallelBuilding = false; # disabled due to rust-lang/rust#16305
  
  