Vendored dependences

[Watson Ladd]

Hello,
I am interested in adding a Chez Scheme port. This will require some
upstream changes so that we have a tarball. Right now they include two
other projects via git submodules: nanopass, zlib, and stex. Should
the tarball I ask for include these dependencies, or should I creat
ports as dependences for each one of them.

Everything else is pretty straightforward.

Sincerely,
Watson