[MIPS] Fix build issue for MIPS

sandbox/linux/seccomp-bpf-helpers/syscall_sets.cc

 // Copyright (c) 2013 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 "sandbox/linux/seccomp-bpf-helpers/syscall_sets.h"
 
 #include "build/build_config.h"
 #include "sandbox/linux/services/linux_syscalls.h"
 
 namespace sandbox {
@@ skipping 911 matching lines @@
       return true;
     default:
       return false;
   }
 }
 
 // Various system calls that need to be researched.
 // TODO(jln): classify this better.
 bool SyscallSets::IsMisc(int sysno) {
   switch (sysno) {
-#if !defined(_mips_)
+#if !defined(__mips__)
     case __NR_getrandom:
 #endif
     case __NR_name_to_handle_at:
     case __NR_open_by_handle_at:
     case __NR_perf_event_open:
     case __NR_syncfs:
     case __NR_vhangup:
 // The system calls below are not implemented.
 #if defined(__i386__) || defined(__x86_64__) || defined(__mips__)
     case __NR_afs_syscall:
@@ skipping 72 matching lines @@
   switch (sysno) {
     case __NR_sysmips:
     case __NR_unused150:
       return true;
     default:
       return false;
   }
 }
 #endif  // defined(__mips__)
 }  // namespace sandbox.