anchor.diff:  
         nativeBuildInputs = [ cmake ];
   
  -      cmakeFlags = [ "-DSPDLOG_BUILD_EXAMPLES=OFF" "-DSPDLOG_BUILD_BENCH=OFF" ];
  +      cmakeFlags = [ "-DSPDLOG_BUILD_EXAMPLE=OFF" "-DSPDLOG_BUILD_BENCH=OFF" ];
   
         outputs = [ "out" "doc" ];
   
  
positive.code: let
    generic = { version, sha256 }:
      stdenv.mkDerivation {
        name = "spdlog-${version}";
        inherit version;
  
        src = fetchFromGitHub {
  
negative.code:       '';
  
        meta = with stdenv.lib; {
          description    = "Very fast, header only, C++ logging library";
          homepage       = "https://github.com/gabime/spdlog";
          license        = licenses.mit;
          maintainers    = with maintainers; [ obadz ];
          platforms      = platforms.all;
  