anchor.diff:        # Update rust to latest stable
         rustChannel.rust
         rustChannel.cargo
  +      rust-cbindgen
       ];
   })
  
positive.code: { releng_pkgs }:
  
  let
    inherit (releng_pkgs.pkgs) rustChannelOf bash autoconf213 clang_4 llvm_4 llvmPackages_4 gcc-unwrapped glibc;
    inherit (releng_pkgs.pkgs.devEnv) gecko;
  
    # Rust 1.28.1-beta6
  
negative.code:     "${gcc-unwrapped}/include/c++/${gcc-unwrapped.version}/x86_64-unknown-linux-gnu"
      "${glibc.dev}/include"
    ];
  
    # Mach needs 0.6.2 at least
    # From https://github.com/NixOS/nixpkgs/blob/cdf90258e6bf911db2b56280301014a88c91be65/pkgs/development/tools/rust/cbindgen/default.nix
    rustPlatform = mkRustPlatform {};
    rust-cbindgen =  rustPlatform.buildRustPackage rec {
      name = "rust-cbindgen-${version}";
      version = "0.6.2";
  
      src = fetchFromGitHub {
        owner = "eqrion";
        repo = "cbindgen";
        rev = "v${version}";
        sha256 = "0hifmn9578cf1r5m4ajazg3rhld2ybd2v48xz04vfhappkarv4w2";
      };
  
      cargoSha256 = "0c3xpzff8jldqbn5a25yy6c2hlz5xy636ml6sj5d24wzcgwg5a2i";
    };
  
  in gecko.overrideDerivation (old: {
    # Dummy src, cannot be null
  