fallback when landlock isn't available

What feature would you like to see?

I use codex on some older linuxes (that I don't control) that don't have landlock, is it possible to add a fallback for the filesystem sandboxing? The seccomp filtering works fine on the network side.

Additional information

Locally we use bwrap (bubblewrap) for filesystem sandboxing and that seems like a reasonable fallback. I went ahead with that and it's working for me: https://github.com/openai/codex/compare/main...tomstitt:codex:bubblewrap-fallback-for-landlock