No longer put cloudabi mutexes in a box.

Cloudabi mutexes may be moved safely.

Author: m-ou-se

library/std/src/sys/cloudabi/mutex.rs

@@ -15,7 +15,7 @@ extern "C" {
 // implemented identically.
 pub struct Mutex(RWLock);
 
-pub type MovableMutex = Box<Mutex>;
+pub type MovableMutex = Mutex;
 
 pub unsafe fn raw(m: &Mutex) -> *mut AtomicU32 {
     rwlock::raw(&m.0)