Add a test for the {{{__sync_lock_test_and_set}}} intrinsic. Refs #1738.

git-svn-id: file:///svn/toku/tokudb@11676 c7de825b-a66e-492c-adef-691d508d4ae1

newbrt/locking-benchmarks/mfence-benchmark.c

@@ -62,7 +62,7 @@ static inline void sfence (void) {
 
 int lock_for_lock_and_unlock;
 static inline void lock_and_unlock (void) {
-    __sync_lock_test_and_set(&lock_for_lock_and_unlock, 1);
+    (void*)__sync_lock_test_and_set(&lock_for_lock_and_unlock, 1);
     __sync_lock_release(&lock_for_lock_and_unlock);
 }