Test mutex locking

Author: bjorn3

example/std_example.rs

@@ -6,6 +6,9 @@ use std::intrinsics;
 
 
 fn main() {
+    let mutex = std::sync::Mutex::new(());
+    mutex.lock().unwrap();
+
     let _ = ::std::iter::repeat('a' as u8).take(10).collect::<Vec<_>>();
     let stderr = ::std::io::stderr();
     let mut stderr = stderr.lock();