BinaryBuilderBase.GitSource how to recurse submodules?

In my build_tarballs.jl, I have a GitSource that has submodules. Looking at the source code for BinaryBuilderBase.GitSource’s setup, there doesn’t seem to be a way currently to for the clone to pass --recurse-submodules. Is this functionality available in BinaryBuilderBase, or should I change my original repo to not use submodules?

Run the git submodule command manually in the build script:

We are limited by what the LibGit2 standard library can do, which doesn’t include submodule management.