Build PPAPI NaCl Glibc tests with GN

ppapi/native_client/src/untrusted/irt_stub/ppapi_plugin_start.c

 /*
  * Copyright (c) 2011 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 <stdlib.h>
 #include <string.h>
 #include <unistd.h>
 
 #include "native_client/src/include/elf32.h"
 #include "native_client/src/include/elf_auxv.h"
 #include "native_client/src/untrusted/irt/irt.h"
 #include "ppapi/nacl_irt/public/irt_ppapi.h"
 #include "ppapi/native_client/src/shared/ppapi_proxy/ppruntime.h"
 #include "ppapi/native_client/src/untrusted/irt_stub/thread_creator.h"
 
 static void fatal_error(const char *message) {
-  write(2, message, strlen(message));
+  ssize_t wrote __attribute__((unused));
+  wrote = write(2, message, strlen(message));
   _exit(127);
 }
 
 /*
  * TODO(mcgrathr): This extremely stupid function should not exist.
  * If the startup calling sequence were sane, this would be done
  * someplace that has the initial pointer locally rather than stealing
  * it from environ.
  * See http://code.google.com/p/nativeclient/issues/detail?id=651
  */
@@ skipping 31 matching lines @@
 
   struct nacl_irt_ppapihook hooks;
   if (sizeof(hooks) != query_func(NACL_IRT_PPAPIHOOK_v0_1,
                                   &hooks, sizeof(hooks)))
     fatal_error("PpapiPluginStart: PPAPI hooks not found\n");
 
   __nacl_register_thread_creator(&hooks);
 
   return hooks.ppapi_start(funcs);
 }