We have switched to Nix as internal dependency manager for our C++ project. It is really exciting! No more "after commit XXX you need to (re)build/update YYY with ZZZ". Developers just type `nix-shell` and get sane guaranted to work environment on their local machines corresponding to git HEAD. If we need to add or patch dependency we just edit and commit nix file. And if developer need to rollback to old commit/branch it will get old/custom environment from cache without submodule rebuilds.