anchor.diff:        --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 ];
  +  buildInputs = [ which file perl curl python27 makeWrapper git valgrind procps ];
   
     enableParallelBuilding = false; # disabled due to rust-lang/rust#16305
   
  
positive.code: { stdenv, fetchurl, fetchgit, which, file, perl, curl, python27, makeWrapper
  , tzdata, git, valgrind
  }:
  
  assert stdenv.gcc.gcc != null;
  
negative.code: 
    src = fetchgit {
      url = https://github.com/rust-lang/rust;
      rev = "34d680009205de2302b902d8f9f5f7ae7a042f1a";
      sha256 = "0qj9b8yzvks42kqr5kxmrq9jwsaj1hmnb156sqjcfywcsdvkzjfw";
    };
  
    # We need rust to build rust. If we don't provide it, configure will try to download it.
  