refactor(3p/nix/libexpr): Store nix::Env values in a std::vector r/1376

This has several advantages:

* we can ensure that the vector is traced by the GC
* we don't need to unsafely allocate memory to make an Env

Note that there was previously a check about the size of the
environment, but it's unclear why this was the case (git history
yielded nothing interesting) and it seems to have no effect.

Change-Id: I4998b879a728a6fb68e1bd187c521e2304e5047e
Reviewed-on: https://cl.tvl.fyi/c/depot/+/1265
Tested-by: BuildkiteCI
Reviewed-by: isomer <isomer@tvl.fyi>
Reviewed-by: Kane York <rikingcoding@gmail.com>
Reviewed-by: glittershark <grfn@gws.fyi>

0 files changed, 0 insertions, 0 deletions