Replace use of deprecated C Standard library headers in C++ code.

Change-Id: I9fa6630c7e4bdb2897df34d417635d8c7d8253bc
Signed-off-by: Tyler Chatow <tchatow@gmail.com>
diff --git a/aos/ipc_lib/queue_racer.h b/aos/ipc_lib/queue_racer.h
index 7e92693..ea0238e 100644
--- a/aos/ipc_lib/queue_racer.h
+++ b/aos/ipc_lib/queue_racer.h
@@ -1,7 +1,7 @@
 #ifndef AOS_IPC_LIB_QUEUE_RACER_H_
 #define AOS_IPC_LIB_QUEUE_RACER_H_
 
-#include <string.h>
+#include <cstring>
 
 #include "aos/ipc_lib/lockless_queue.h"