Added support for NaCl IO to use the IRT Extension API.

native_client_sdk/src/libraries/nacl_io/kernel_wrap_newlib.cc

Index: native_client_sdk/src/libraries/nacl_io/kernel_wrap_newlib.cc
diff --git a/native_client_sdk/src/libraries/nacl_io/kernel_wrap_newlib.cc b/native_client_sdk/src/libraries/nacl_io/kernel_wrap_newlib.cc
index fecd72f9916c816c4a6183cc261cedaefdcace26..f9aa7ffba1e605dd8d48d4f2ab2b322e1d319a96 100644
--- a/native_client_sdk/src/libraries/nacl_io/kernel_wrap_newlib.cc
+++ b/native_client_sdk/src/libraries/nacl_io/kernel_wrap_newlib.cc
@@ -3,12 +3,12 @@
 // found in the LICENSE file.
 
 #include <sys/types.h>  // Include something that will define __GLIBC__.
+#include "nacl_io/kernel_wrap.h" // IRT_EXT is turned on in this header.
 
 // The entire file is wrapped in this #if. We do this so this .cc file can be
 // compiled, even on a non-newlib build.
-#if defined(__native_client__) && !defined(__GLIBC__) && !defined(__BIONIC__)
-
-#include "nacl_io/kernel_wrap.h"
+#if !defined(__NACL_IO_IRT_EXT__) && defined(__native_client__) && \
+    !defined(__GLIBC__) && !defined(__BIONIC__)
 
 #include <dirent.h>
 #include <errno.h>