pkg is a simple, minimal dependency manager based on Git.
It clones your cycle-free dependency tree recursively and creates a CMakeLists.txt file with all dependencies in topological order.
Example .pkg file:
[fmt]
url=git@github.com:motis-project/fmt.git
branch=master
commit=3eca62d66c7c9a2ca97dc8381299d911978b9fb2