anchor.diff:  { lib
   , stdenv
   , fetchFromGitHub
  +, fetchpatch
   , cmake
   , curl
   , openssl
  
positive.code: 
    patches = [
      ./cmake-dirs.patch
    ];
  
    # Builds in 2+h with 2 cores, and ~10m with a big-parallel builder.
    requiredSystemFeatures = [ "big-parallel" ];
  
negative.code: 
  stdenv.mkDerivation rec {
    pname = "aws-sdk-cpp";
    version = if stdenv.system == "i686-linux" then "1.9.150"
      else "1.9.238";
  
    src = fetchFromGitHub {
      owner = "aws";
      repo = "aws-sdk-cpp";
      rev = version;
      sha256 = if version == "1.9.150" then "fgLdXWQKHaCwulrw9KV3vpQ71DjnQAL4heIRW7Rk7UY="
        else "sha256-pEmsTfZXsvJMV79dGkjDNbUVajwyoYgzE5DCsC53pGY=";
    };
  
    postPatch = ''
  