std: Get stdtest all passing again

This commit brings the library up-to-date in order to get all tests passing
again

src/libstd/unstable/mutex.rs

@@ -333,12 +333,12 @@ mod test {
     fn somke_cond() {
         static mut lock: Mutex = MUTEX_INIT;
         unsafe {
+            lock.lock();
             let t = do Thread::start {
                 lock.lock();
                 lock.signal();
                 lock.unlock();
             };
-            lock.lock();
             lock.wait();
             lock.unlock();
             t.join();

src/libstd/unstable/stack.rs

@@ -24,11 +24,6 @@
 //! detection is not guaranteed to continue in the future. Usage of this module
 //! is discouraged unless absolutely necessary.
 
-use rt::task::Task;
-use option::None;
-use rt::local::Local;
-use unstable::intrinsics;
-
 static RED_ZONE: uint = 20 * 1024;
 
 /// This function is invoked from rust's current __morestack function. Segmented
@@ -41,6 +36,10 @@ static RED_ZONE: uint = 20 * 1024;
                   //   irrelevant for documentation purposes.
 #[cfg(not(test))] // in testing, use the original libstd's version
 pub extern "C" fn rust_stack_exhausted() {
+    use rt::task::Task;
+    use option::None;
+    use rt::local::Local;
+    use unstable::intrinsics;
 
     unsafe {
         // We're calling this function because the stack just ran out. We need

src/libstd/unstable/sync.rs

@@ -161,9 +161,8 @@ impl<T:Send> Exclusive<T> {
 mod tests {
     use option::*;
     use prelude::*;
-    use super::{Exclusive, UnsafeArc, atomic};
+    use super::Exclusive;
     use task;
-    use mem::size_of;
 
     #[test]
     fn exclusive_new_arc() {