Tiny fixes for latest Rust

Cargo.toml

@@ -8,4 +8,7 @@ documentation = "http://bsago.me/doc/users/"
 homepage = "https://github.com/ogham/rust-users"
 license = "MIT"
 readme = "README.md"
-version = "0.2.2"
+version = "0.2.3"
+
+[dependencies]
+libc = "0.1.1"

src/lib.rs

@@ -1,7 +1,8 @@
 #![crate_name = "users"]
 #![crate_type = "rlib"]
 #![crate_type = "dylib"]
-#![feature(collections, core, libc, std_misc)]
+#![allow(unused_features)]
+#![feature(core, libc, std_misc)]
 
 //! This is a library for getting information on Unix users and groups.
 //!