Fix Mac bootstrap sandbox for 64-bit builds

sandbox/mac/os_compatibility.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 "sandbox/mac/os_compatibility.h"
 
 #include <servers/bootstrap.h>
 #include <unistd.h>
 
 #include "base/mac/mac_util.h"
 
 namespace sandbox {
 
 namespace {
 
+#pragma pack(push, 4)
 // Verified from launchd-329.3.3 (10.6.8).
 struct look_up2_request_10_6 {
   mach_msg_header_t Head;
   NDR_record_t NDR;
   name_t servicename;
   pid_t targetpid;
   uint64_t flags;
 };
 
 struct look_up2_reply_10_6 {
@@ skipping 23 matching lines @@
 //   launchd-442.26.2 (10.8.5)
 //   launchd-842.1.4 (10.9.0)
 typedef int vproc_gsk_t;  // Defined as an enum in liblaunch/vproc_priv.h.
 struct swap_integer_request_10_6 {
   mach_msg_header_t Head;
   NDR_record_t NDR;
   vproc_gsk_t inkey;
   vproc_gsk_t outkey;
   int64_t inval;
 };
+#pragma pack(pop)
 
 // TODO(rsesek): Libc provides strnlen() starting in 10.7.
 size_t strnlen(const char* str, size_t maxlen) {
   size_t len = 0;
   for (; len < maxlen; ++len, ++str) {
     if (*str == '\0')
       break;
   }
   return len;
 }
@@ skipping 55 matching lines @@
   } else {
     DLOG(ERROR) << "Unknown OS, using launchd compatibility shim from 10.7.";
     shim.look_up2_get_request_name =
         &LaunchdLookUp2GetRequestName<look_up2_request_10_7>;
   }
 
   return shim;
 }
 
 }  // namespace sandbox