Cleanup: Mark a function as x86-64 / ARM only. Found by clang.

components/nacl/loader/nonsfi/nonsfi_sandbox.cc

 // 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 "components/nacl/loader/nonsfi/nonsfi_sandbox.h"
 
 #include <errno.h>
 #include <fcntl.h>
 #include <linux/net.h>
 #include <sys/prctl.h>
@@ skipping 114 matching lines @@
   const uint32_t denied_flag_mask = ~(MAP_SHARED | MAP_PRIVATE |
                                       MAP_ANONYMOUS | MAP_STACK | MAP_FIXED);
   // TODO(hamaji): Disallow RWX mmap.
   return sb->Cond(3, ErrorCode::TP_32BIT,
                   ErrorCode::OP_HAS_ANY_BITS,
                   denied_flag_mask,
          sb->Trap(sandbox::CrashSIGSYS_Handler, NULL),
                   RestrictMemoryProtection(sb, 2));
 }
 
+#if defined(__x86_64__) || defined(__arm__)
 ErrorCode RestrictSocketpair(SandboxBPF* sb) {
   // Only allow AF_UNIX, PF_UNIX. Crash if anything else is seen.
   COMPILE_ASSERT(AF_UNIX == PF_UNIX, af_unix_pf_unix_different);
   return sb->Cond(0, ErrorCode::TP_32BIT,
                   ErrorCode::OP_EQUAL, AF_UNIX,
                   ErrorCode(ErrorCode::ERR_ALLOWED),
          sb->Trap(sandbox::CrashSIGSYS_Handler, NULL));
 }
+#endif
 
 bool IsGracefullyDenied(int sysno) {
   switch (sysno) {
     // libevent tries this first and then falls back to poll if
     // epoll_create fails.
     case __NR_epoll_create:
     // third_party/libevent uses them, but we can just return -1 from
     // them as it is just checking getuid() != geteuid() and
     // getgid() != getegid()
 #if defined(__i386__) || defined(__arm__)
@@ skipping 154 matching lines @@
       scoped_ptr<sandbox::SandboxBPFPolicy>(
           new nacl::nonsfi::NaClNonSfiBPFSandboxPolicy()));
   if (!sandbox_is_initialized)
     return false;
   RunSandboxSanityChecks();
   return true;
 }
 
 }  // namespace nonsfi
 }  // namespace nacl