Put __pnacl_real_irt_interface variable in bss instead of common.

ppapi/native_client/src/untrusted/pnacl_irt_shim/shim_ppapi.c

 /*
  * Copyright (c) 2012 The Chromium Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "ppapi/native_client/src/untrusted/pnacl_irt_shim/shim_ppapi.h"
 
 #include <string.h>
 #include "native_client/src/include/nacl_macros.h"
@@ skipping 72 matching lines @@
 static int is_irt_interface_whitelisted(const char *interface_name) {
   int i;
   for (i = 0; i < NACL_ARRAY_SIZE(irt_interface_whitelist); i++) {
     if (mystrcmp(interface_name, irt_interface_whitelist[i]) == 0) {
       return 1;
     }
   }
   return 0;
 }
 
-TYPE_nacl_irt_query __pnacl_real_irt_interface;
+TYPE_nacl_irt_query __pnacl_real_irt_interface = NULL;
 
 /*
  * These remember the interface pointers the user registers by calling the
  * IRT entry point.
  */
 static struct PP_StartFunctions user_start_functions;
 
 static int32_t wrap_PPPInitializeModule(PP_Module module_id,
                                         PPB_GetInterface get_browser_intf) {
   __set_real_Pnacl_PPBGetInterface(get_browser_intf);
@@ skipping 63 matching lines @@
    */
   struct nacl_irt_ppapihook *dest = table;
   if (sizeof *dest <= tablesize) {
     dest->ppapi_start = wrap_ppapi_start;
     dest->ppapi_register_thread_creator =
         real_irt_ppapi_hook.ppapi_register_thread_creator;
     return sizeof *dest;
   }
   return 0;
 }