diff --git a/libs/pbd/pbd/abstract_ui.h b/libs/pbd/pbd/abstract_ui.h
index 04d0a38e85..8e386aa4eb 100644
--- a/libs/pbd/pbd/abstract_ui.h
+++ b/libs/pbd/pbd/abstract_ui.h
@@ -75,21 +75,8 @@ class ABSTRACT_UI_API AbstractUI : public BaseUI
         };
 	typedef typename RequestBuffer::rw_vector RequestBufferVector;
 
-#ifdef COMPILER_MSVC // ?? (not needed for ming32 nor mingw64)
-
-	struct pthread_cmp
-	{
-		bool operator() (const ptw32_handle_t& thread1, const ptw32_handle_t& thread2)
-		{
-			return thread1.p < thread2.p;
-		}
-	};
-	typedef typename std::map<pthread_t,RequestBuffer*, pthread_cmp>::iterator RequestBufferMapIterator;
-	typedef std::map<pthread_t,RequestBuffer*, pthread_cmp> RequestBufferMap;
-#else
 	typedef typename std::map<pthread_t,RequestBuffer*>::iterator RequestBufferMapIterator;
 	typedef std::map<pthread_t,RequestBuffer*> RequestBufferMap;
-#endif
 
 	RequestBufferMap request_buffers;
         static Glib::Threads::Private<RequestBuffer> per_thread_request_buffer;