diff --git a/fio.h b/fio.h
index 28198b9..393f381 100644
--- a/fio.h
+++ b/fio.h
@@ -20,7 +20,7 @@
 #include "thread_options.h"
 #include "flist.h"
 #include "fifo.h"
-#include "rbtree.h"
+#include "lib/rbtree.h"
 #include "arch/arch.h"
 #include "os/os.h"
 #include "mutex.h"
@@ -551,4 +551,6 @@
 extern const char *fio_get_arch_string(int);
 extern const char *fio_get_os_string(int);
 
+#define ARRAY_SIZE(x) (sizeof((x)) / (sizeof((x)[0])))
+
 #endif