anchor.diff:      "${gcc-unwrapped}/include/c++/${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
  
positive.code:       # Update rust to latest stable
        rustChannel.rust
        rustChannel.cargo
      ];
  })
  
negative.code: { releng_pkgs }:
  
  let
    inherit (releng_pkgs.lib) mkRustPlatform ;
    inherit (releng_pkgs.pkgs) rustChannelOf bash autoconf213 clang_4 llvm_4 llvmPackages_4 gcc-unwrapped glibc fetchFromGitHub;
    inherit (releng_pkgs.pkgs.devEnv) gecko;
  
    # Rust 1.28.1-beta6
  