Ensure syscall functions are consistently prefixed with "NaClSys"

src/trusted/service_runtime/include/bits/nacl_syscalls.h

 /*
  * 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.
  */
 
 /*
  * NaCl kernel / service run-time system call numbers
  */
 
@@ skipping 15 matching lines @@
 #define NACL_sys_close                  11
 #define NACL_sys_read                   12
 #define NACL_sys_write                  13
 #define NACL_sys_lseek                  14
 #define NACL_sys_ioctl                  15
 #define NACL_sys_stat                   16
 #define NACL_sys_fstat                  17
 #define NACL_sys_chmod                  18
 /* no fchmod emulation on windows */
 
-#define NACL_sys_sysbrk                 20
+#define NACL_sys_brk                    20
 #define NACL_sys_mmap                   21
 #define NACL_sys_munmap                 22
 
 #define NACL_sys_getdents               23
 
 #define NACL_sys_mprotect               24
 
 #define NACL_sys_exit                   30
 #define NACL_sys_getpid                 31
 #define NACL_sys_sched_yield            32
@@ skipping 50 matching lines @@
 
 /*
  * This syscall number is set aside for use in tests that add a
  * syscall that must coexist with the normal syscalls.
  */
 #define NACL_sys_test_syscall_1         111
 
 #define NACL_MAX_SYSCALLS               112
 
 #endif