EOPNOTSUPP not exported by nix crate on FreeBSD

On FreeBSD the libc crate defines ENOTSUP as an alias for EOPNOTSUPP. The nix crate however only exports ENOTSUP. Would it be possible to switch to using ENOTSUP in sandboxfs instead for FreeBSD? It's likely the same way on the other BSDs.

sandboxfs/src/nodes/mod.rs

Line 117 in 6d8108f

return Err(nix::Error::from_errno(Errno::EOPNOTSUPP));

sandboxfs/src/nodes/mod.rs

Line 155 in 6d8108f

return Err(nix::Error::from_errno(Errno::EOPNOTSUPP));

[jmmv]

See nix-rust/nix#969.

[jmmv]

OK, the dependent PR for nix has been fixed. Once it's released, we should be able to switch to ENOTSUP instead.