Mac OS X support

I did a cargo new and added only zbus lib and it does not compile :

➜  zbus git:(master) ✗ cargo run
   Compiling proc-macro2 v1.0.21
   Compiling unicode-xid v0.2.1
   Compiling syn v1.0.41
   Compiling serde_derive v1.0.116
   Compiling serde v1.0.116
   Compiling bitflags v1.2.1
   Compiling libc v0.2.77
   Compiling byteorder v1.3.4
   Compiling nix v0.17.0
   Compiling cfg-if v0.1.10
   Compiling void v1.0.2
   Compiling once_cell v1.4.1
   Compiling scoped-tls v1.0.0
   Compiling fastrand v1.3.5
   Compiling quote v1.0.7
   Compiling enumflags2_derive v0.6.4
   Compiling derivative v2.1.1
   Compiling serde_repr v0.1.6
   Compiling toml v0.5.6
   Compiling enumflags2 v0.6.4
   Compiling proc-macro-crate v0.1.5
   Compiling zvariant_derive v2.2.0
   Compiling zbus_macros v1.1.0
   Compiling zvariant v2.2.0
   Compiling zbus v1.1.1
error[E0432]: unresolved import `nix::sys::socket::sockopt::PeerCredentials`
   --> /Users/moyowi/.cargo/registry/src/github.com-1ecc6299db9ec823/zbus-1.1.1/src/connection.rs:177:44
    |
177 |         use nix::sys::socket::{getsockopt, sockopt::PeerCredentials};
    |                                            ^^^^^^^^^^^^^^^^^^^^^^^^ no `PeerCredentials` in `sys::socket::sockopt`

error: aborting due to previous error

For more information about this error, try `rustc --explain E0432`.
error: could not compile `zbus`.

To learn more, run the command again with --verbose.