use os_bsd and OS_BSD and add some OS_FREEBSD conditions

base/process_util_posix.cc

 // Copyright (c) 2011 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 <dirent.h>
 #include <errno.h>
 #include <fcntl.h>
 #include <signal.h>
 #include <stdlib.h>
 #include <sys/resource.h>
@@ skipping 15 matching lines @@
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/process_util.h"
 #include "base/stringprintf.h"
 #include "base/synchronization/waitable_event.h"
 #include "base/third_party/dynamic_annotations/dynamic_annotations.h"
 #include "base/threading/platform_thread.h"
 #include "base/threading/thread_restrictions.h"
 #include "base/time.h"
 
+#if defined(OS_FREEBSD)
+#include <sys/event.h>
+#include <sys/ucontext.h>
+#endif
+
 #if defined(OS_MACOSX)
 #include <crt_externs.h>
 #include <sys/event.h>
 #else
 extern char** environ;
 #endif
 
 namespace base {
 
 namespace {
@@ skipping 1255 matching lines @@
   if (IsChildDead(process))
     return;
 
   BackgroundReaper* reaper = new BackgroundReaper(process, 0);
   PlatformThread::CreateNonJoinable(0, reaper);
 }
 
 #endif  // !defined(OS_MACOSX)
 
 }  // namespace base