anchor.diff:  { lib
  +, bazel_4
   , buildBazelPackage
   , fetchFromGitHub
  +, fetchpatch
   , stdenv
   , cmake
   , gn
  
positive.code:     ninja
    ];
  
    fetchAttrs = {
      sha256 = "sha256:0vnl0gq6nhvyzz39jg1bvvna0xyhxalg71bp1jbxib7ql026004r";
      dontUseCmakeConfigure = true;
      dontUseGnConfigure = true;
      preInstall = ''
  
negative.code:     dontUseGnConfigure = true;
      dontUseNinjaInstall = true;
      preConfigure = ''
        sed -i 's,#!/usr/bin/env bash,#!${stdenv.shell},' $bazelOut/external/rules_foreign_cc/foreign_cc/private/framework/toolchains/linux_commands.bzl
  
        # Add paths to Nix store back.
        sed -i \
  