std::os::unix::OsStrExt is now std::os::unix::ffi::OsStrExt

Also remove obsolete feature gate.

Author: lilyball

examples/sine.rs

@@ -1,5 +1,5 @@
 #![allow(non_snake_case)]
-#![feature(libc,io)]
+#![feature(libc)]
 
 #[macro_use]
 extern crate lua;

src/lib.rs

@@ -15,7 +15,7 @@ use std::{fmt, mem, ptr, str, slice};
 use std::ffi::{AsOsStr, CStr, CString};
 use std::marker;
 use std::num::SignedInt;
-use std::os::unix::OsStrExt;
+use std::os::unix::ffi::OsStrExt;
 use std::path::Path;
 
 /// Human-readable major version string