make sure /run/current-system/sw/bin ends up visible in the container
Side issue from https://github.com/ValveSoftware/steam-runtime/issues/604, where a NixOS user's log said:
13:24:48.739187: pressure-vessel-wrap[54736]: W: "/run/current-system/sw/bin/getent" is unlikely to appear in "/run/host"
We should probably let /run/current-system/sw/bin
(or one of its ancestors, maybe /run/current-system
) inherit into the container as-is, like we do for /nix
already, so that a symlink /overrides/bin/getent -> /run/current-system/sw/bin/getent
will work.