Fix no_std on redox

Apparently a root-level cfg does not go well with a root-level no_std

src/sys_utsname/src/lib.rs

@@ -1,28 +1,32 @@
 //! sys/utsname implementation for Redox, following http://pubs.opengroup.org/onlinepubs/7908799/xsh/sysutsname.h.html
 
 #![no_std]
-#![cfg(target_os = "linux")]
 
-extern crate platform;
+#[cfg(target_os = "linux")]
+mod inner {
+    extern crate platform;
 
-use core::ptr;
-use platform::types::*;
+    use core::ptr;
+    use self::platform::types::*;
 
-const LENGTH: usize = 65;
+    const LENGTH: usize = 65;
 
-#[allow(non_camel_case)]
-#[no_mangle]
-#[repr(C)]
-pub struct utsname {
-    pub sysname:    [c_char; LENGTH],
-    pub nodename:   [c_char; LENGTH],
-    pub release:    [c_char; LENGTH],
-    pub version:    [c_char; LENGTH],
-    pub machine:    [c_char; LENGTH],
-    pub domainname: [c_char; LENGTH]
-}
-
-#[no_mangle]
-pub unsafe extern "C" fn uname(uts: *mut utsname) -> c_int {
-    platform::uname(uts as usize)
+    #[allow(non_camel_case)]
+    #[no_mangle]
+    #[repr(C)]
+    pub struct utsname {
+        pub sysname:    [c_char; LENGTH],
+        pub nodename:   [c_char; LENGTH],
+        pub release:    [c_char; LENGTH],
+        pub version:    [c_char; LENGTH],
+        pub machine:    [c_char; LENGTH],
+        pub domainname: [c_char; LENGTH]
+    }
+
+    #[no_mangle]
+    pub unsafe extern "C" fn uname(uts: *mut utsname) -> c_int {
+        platform::uname(uts as usize)
+    }
 }
+#[cfg(target_os = "linux")]
+pub use inner::*;