Remove OS(IOS) and OS(MAC_OS_X) guards.

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 37 matching lines @@
 #include "wtf/UnusedParam.h"
 #include "wtf/WTFThreadData.h"
 #include <errno.h>
 
 #if !COMPILER(MSVC)
 #include <limits.h>
 #include <sched.h>
 #include <sys/time.h>
 #endif
 
-#if OS(MAC_OS_X) && __MAC_OS_X_VERSION_MIN_REQUIRED >= 1060
+#if OS(DARWIN) && __MAC_OS_X_VERSION_MIN_REQUIRED >= 1060
 #include <objc/objc-auto.h>
 #endif
 
 namespace WTF {
 
 class PthreadState {
     WTF_MAKE_FAST_ALLOCATED;
 public:
     enum JoinableState {
         Joinable, // The default thread state. The thread can be joined on.
@@ skipping 129 matching lines @@
 }
 
 void initializeCurrentThreadInternal(const char* threadName)
 {
 #if HAVE(PTHREAD_SETNAME_NP)
     pthread_setname_np(threadName);
 #else
     UNUSED_PARAM(threadName);
 #endif
 
-#if OS(MAC_OS_X) && __MAC_OS_X_VERSION_MIN_REQUIRED >= 1060
+#if OS(DARWIN) && __MAC_OS_X_VERSION_MIN_REQUIRED >= 1060
     // All threads that potentially use APIs above the BSD layer must be registered with the Objective-C
     // garbage collector in case API implementations use garbage-collected memory.
     objc_registerThreadWithCollector();
 #endif
 
     ThreadIdentifier id = identifierByPthreadHandle(pthread_self());
     ASSERT(id);
     ThreadIdentifierData::initialize(id);
 }
 
@@ skipping 167 matching lines @@
 
 void ThreadCondition::broadcast()
 {
     int result = pthread_cond_broadcast(&m_condition);
     ASSERT_UNUSED(result, !result);
 }
 
 } // namespace WTF
 
 #endif // USE(PTHREADS)