makeObjectCount is used for error reporting without sync

volatile is enough then.
Found by coverity.

src/main/java/org/apache/commons/pool3/impl/GenericObjectPool.java

@@ -117,7 +117,7 @@ private static void wait(final Object obj, final Duration duration) throws Inter
      */
     private final AtomicLong createCount = new AtomicLong();
 
-    private long makeObjectCount;
+    private volatile long makeObjectCount;
 
     private final Object makeObjectCountLock = new Object();