src: fix build on freebsd

src/debug.cc

 // Copyright 2012 the V8 project 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 "src/v8.h"
 
 #include "src/api.h"
 #include "src/arguments.h"
 #include "src/bootstrapper.h"
 #include "src/code-stubs.h"
@@ skipping 555 matching lines @@
   thread_local_.break_frame_id_ = StackFrame::NO_ID;
   thread_local_.last_step_action_ = StepNone;
   thread_local_.last_statement_position_ = RelocInfo::kNoPosition;
   thread_local_.step_count_ = 0;
   thread_local_.last_fp_ = 0;
   thread_local_.queued_step_count_ = 0;
   thread_local_.step_into_fp_ = 0;
   thread_local_.step_out_fp_ = 0;
   // TODO(isolates): frames_are_dropped_?
   base::NoBarrier_Store(&thread_local_.current_debug_scope_,
-                        static_cast<base::AtomicWord>(NULL));
+                        static_cast<base::AtomicWord>(0));
   thread_local_.restarter_frame_function_pointer_ = NULL;
 }
 
 
 char* Debug::ArchiveDebug(char* storage) {
   char* to = storage;
   MemCopy(to, reinterpret_cast<char*>(&thread_local_), sizeof(ThreadLocal));
   ThreadInit();
   return storage + ArchiveSpacePerThread();
 }
@@ skipping 2905 matching lines @@
   logger_->DebugEvent("Put", message.text());
 }
 
 
 void LockingCommandMessageQueue::Clear() {
   base::LockGuard<base::Mutex> lock_guard(&mutex_);
   queue_.Clear();
 }
 
 } }  // namespace v8::internal