NaCl: Fix nacl_io library to build with -Wstrict-prototypes

native_client_sdk/src/libraries/nacl_io/h_errno.c

 // Copyright 2014 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 "nacl_io/ossocket.h"
 
 #if defined(PROVIDES_SOCKET_API) && !defined(__GLIBC__)
 
 #include <stdlib.h>
 #include <pthread.h>
 
 static pthread_key_t s_h_errno_key;
 static pthread_once_t s_h_errno_once = PTHREAD_ONCE_INIT;
 
-static void __h_errno_create() {
+static void __h_errno_create(void) {
   pthread_key_create(&s_h_errno_key, NULL);
 }
 
-int *__h_errno_location() {
+int *__h_errno_location(void) {
   int* h_errno_ptr;
   pthread_once(&s_h_errno_once, __h_errno_create);
   h_errno_ptr = (int *) pthread_getspecific(s_h_errno_key);
 
   if (NULL == h_errno_ptr) {
     h_errno_ptr = (int *) malloc(sizeof(int));
     pthread_setspecific(s_h_errno_key, h_errno_ptr);
     *h_errno_ptr = 0;
   }
 
   return h_errno_ptr;
 }
 
 #if defined(__BIONIC__)
-int *__get_h_errno() {
+int *__get_h_errno(void) {
   return __h_errno_location();
 }
 #endif
 
 #endif  // defined(PROVIDES_SOCKET_API) && !defined(__GLIBC__)