msgpack-cxx: use finalAttrs pattern

pkgs/development/libraries/msgpack-cxx/default.nix

···
 , zlib
 }:
 
-stdenv.mkDerivation rec {
+stdenv.mkDerivation (finalAttrs: {
   pname = "msgpack-cxx";
   version = "6.1.0";
 
   src = fetchFromGitHub {
     owner = "msgpack";
     repo = "msgpack-c";
-    rev = "refs/tags/cpp-${version}";
+    rev = "refs/tags/cpp-${finalAttrs.version}";
     hash = "sha256-VqzFmm3MmMhWyooOsz1d9gwwbn/fnnxpkCFwqKR6los=";
   };
 
···
 
   cmakeFlags = [
     "-DMSGPACK_BUILD_DOCS=OFF" # docs are not installed even if built
-  ] ++ lib.optional doCheck "-DMSGPACK_BUILD_TESTS=ON";
+  ] ++ lib.optional finalAttrs.doCheck "-DMSGPACK_BUILD_TESTS=ON";
 
   checkInputs = [
     zlib
···
   meta = with lib; {
     description = "MessagePack implementation for C++";
     homepage = "https://github.com/msgpack/msgpack-c";
-    changelog = "https://github.com/msgpack/msgpack-c/blob/${src.rev}/CHANGELOG.md";
+    changelog = "https://github.com/msgpack/msgpack-c/blob/${finalAttrs.src.rev}/CHANGELOG.md";
     license = licenses.boost;
     maintainers = with maintainers; [ nickcao ];
   };
-}
+})