Fix some issues with the OSX port

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/helpers.c b/helpers.c
index 9c76d30..098195c 100644
--- a/helpers.c
+++ b/helpers.c
@@ -32,8 +32,8 @@
 
 	ret = gettimeofday(&tv, NULL);
 
-	ts->ts_sec = tv.tv_sec;
-	ts->ts_nsec = tv.tv_usec * 1000;
+	ts->tv_sec = tv.tv_sec;
+	ts->tv_nsec = tv.tv_usec * 1000;
 
 	return ret;
 }