anchor.diff: -{ stdenv, fetchFromGitHub, rustPlatform, CoreServices }:
  +{ stdenv, fetchFromGitHub, rustPlatform, CoreServices, darwin }:
   
   rustPlatform.buildRustPackage rec {
     name = "mdbook-${version}";
  
positive.code: 
    cargoSha256 = "0kcc0b2644qbalz7dnqwxsjdmw1h57k0rjrvwqh8apj2sgl64gyv";
  
    buildInputs = stdenv.lib.optionals stdenv.isDarwin [ CoreServices ];
  
    meta = with stdenv.lib; {
      description = "Create books from MarkDown";
  
negative.code:     license = [ licenses.asl20 licenses.mit ];
      maintainers = [ maintainers.havvy ];
      platforms = platforms.all;
    };
  }
  