More header untangling.

Change-Id: I090943775cbda8d9515cdb484957f6b05d5b1799
diff --git a/rsThreadIO.cpp b/rsThreadIO.cpp
index 7182f53..8a0a5dc 100644
--- a/rsThreadIO.cpp
+++ b/rsThreadIO.cpp
@@ -15,8 +15,8 @@
  */
 
 #include "rsContext.h"
-
 #include "rsThreadIO.h"
+#include "rsgApiStructs.h"
 
 #include <unistd.h>
 #include <sys/types.h>