Build WTF as dll in component build

Source/wtf/ThreadingPthreads.cpp

 /*
  * Copyright (C) 2007, 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Justin Haygood (jhaygood@reaktix.com)
  * Copyright (C) 2011 Research In Motion Limited. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
@@ skipping 94 matching lines @@
 void threadWasJoined(ThreadIdentifier);
 
 static Mutex& threadMapMutex()
 {
     DEFINE_STATIC_LOCAL(Mutex, mutex, ());
     return mutex;
 }
 
 void initializeThreading()
 {
-    if (atomicallyInitializedStaticMutex)
-        return;
+    // This should only be called once.
+    ASSERT(!atomicallyInitializedStaticMutex);
 
     WTF::double_conversion::initialize();
     // StringImpl::empty() does not construct its static string in a threadsafe fashion,
     // so ensure it has been initialized from here.
     StringImpl::empty();
     atomicallyInitializedStaticMutex = new Mutex;
     threadMapMutex();
     initializeRandomNumberGenerator();
     ThreadIdentifierData::initializeOnce();
     StackStats::initialize();
@@ skipping 259 matching lines @@
 
 void ThreadCondition::broadcast()
 {
     int result = pthread_cond_broadcast(&m_condition);
     ASSERT_UNUSED(result, !result);
 }
 
 } // namespace WTF
 
 #endif // USE(PTHREADS)