Increase the number of pthread keys available to the IRT

src/untrusted/irt/irt_private_pthread.c

 /*
  * Copyright (c) 2012 The Native Client 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 <errno.h>
 #include <pthread.h>
 #include <unistd.h>
 
 #include "native_client/src/untrusted/nacl/tls.h"
 
 /*
  * libstdc++ makes minimal use of pthread_key_t stuff.
  */
 
 #undef  PTHREAD_KEYS_MAX
-#define PTHREAD_KEYS_MAX        16
+#define PTHREAD_KEYS_MAX        32
 
 #define NC_TSD_NO_MORE_KEYS     irt_tsd_no_more_keys()
 static void irt_tsd_no_more_keys(void) {
   static const char msg[] = "IRT: too many pthread keys\n";
   write(2, msg, sizeof msg - 1);
 }
 
 #define NACL_IN_IRT
 
 /* @IGNORE_LINES_FOR_CODE_HYGIENE[2] */
 #include "native_client/src/untrusted/pthread/nc_init_private.c"
 #include "native_client/src/untrusted/pthread/nc_thread.c"