[paulnechifor]

I don't think recompilation is required. You can use proot (like chroot) to make a local dir look like "/nix" to subprocesses. I've seen it here (but not tested it): https://gist.github.com/mbbx6spp/4f467adb4e0133063fd87e264c6...

[microtonal]

Yes, that's a similar approach to the use of user namespaces that I mentioned, which also doesn't require recompilation. I guess proot also works on systems with user namespaces disabled (which is sometimes done for security reasons).