[Isolates] Fix compile under Win32 and presumably for FreeBSD, OpenBS...

src/v8threads.cc

 // Copyright 2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 388 matching lines @@
   for (ThreadState* state = FirstThreadStateInUse();
        state != NULL;
        state = state->Next()) {
     if (thread_id == state->id()) {
       state->set_terminate_on_restore(true);
     }
   }
 }
 
 
-// This is the ContextSwitcher singleton. There is at most a single thread
-// running which delivers preemption events to V8 threads.
-ContextSwitcher* ContextSwitcher::singleton_ = NULL;
-
-
 ContextSwitcher::ContextSwitcher(Isolate* isolate, int every_n_ms)
   : Thread(isolate),
     keep_going_(true),
     sleep_ms_(every_n_ms) {
 }
 
 
 // Set the scheduling interval of V8 threads. This function starts the
 // ContextSwitcher thread if needed.
 void ContextSwitcher::StartPreemption(int every_n_ms) {
@@ skipping 42 matching lines @@
 // Acknowledge the preemption by the receiving thread.
 void ContextSwitcher::PreemptionReceived() {
   ASSERT(Locker::IsLocked());
   // There is currently no accounting being done for this. But could be in the
   // future, which is why we leave this in.
 }
 
 
 }  // namespace internal
 }  // namespace v8