diff --git a/libs/pbd/pbd/abstract_ui.h b/libs/pbd/pbd/abstract_ui.h
index de119fc238..57ef3a6aac 100644
--- a/libs/pbd/pbd/abstract_ui.h
+++ b/libs/pbd/pbd/abstract_ui.h
@@ -73,20 +73,8 @@ protected:
 	};
 	typedef typename RequestBuffer::rw_vector RequestBufferVector;
 
-#if defined(COMPILER_MINGW) && defined(PTW32_VERSION)
-	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
+	typedef typename std::map<pthread_t, RequestBuffer*, std::less<>>::iterator RequestBufferMapIterator;
+	typedef std::map<pthread_t, RequestBuffer*, std::less<>> RequestBufferMap;
 
 	RequestBufferMap request_buffers;
 
diff --git a/libs/pbd/pbd/abstract_ui.inc.cc b/libs/pbd/pbd/abstract_ui.inc.cc
index f3f735c973..049df1ebde 100644
--- a/libs/pbd/pbd/abstract_ui.inc.cc
+++ b/libs/pbd/pbd/abstract_ui.inc.cc
@@ -32,15 +32,6 @@
 
 #include "pbd/i18n.h"
 
-#ifdef COMPILER_MSVC
-#include <ardourext/misc.h>  // Needed for 'DECLARE_DEFAULT_COMPARISONS'. Objects in an STL container can be
-                             // searched and sorted. Thus, when instantiating the container, MSVC complains
-                             // if the type of object being contained has no appropriate comparison operators
-                             // defined (specifically, if operators '<' and '==' are undefined). This seems
-                             // to be the case with ptw32 'pthread_t' which is a simple struct.
-DECLARE_DEFAULT_COMPARISONS(ptw32_handle_t)
-#endif
-
 using namespace std;
 
 #ifndef NDEBUG
diff --git a/msvc_extra_headers/ardourext/misc.h.input b/msvc_extra_headers/ardourext/misc.h.input
index 497224a556..f20c70607f 100644
--- a/msvc_extra_headers/ardourext/misc.h.input
+++ b/msvc_extra_headers/ardourext/misc.h.input
@@ -242,14 +242,6 @@ inline int64_t abs(int64_t val) throw()
 #if defined(LIBPBD_DLL) || defined(PBD_IS_IN_WIN_STATIC_LIB)
 #include <pbd/msvc_pbd.h>
 
-#ifdef LIBPBD_DLL
-#define DEFAULT_COMPARISONS_DEFINED
-#define DECLARE_DEFAULT_COMPARISONS(Type) \
-	LIBPBD_API bool operator >  (const Type& lhs, const Type& rhs); \
-	LIBPBD_API bool operator <  (const Type& lhs, const Type& rhs); \
-	LIBPBD_API bool operator != (const Type& lhs, const Type& rhs); \
-	LIBPBD_API bool operator == (const Type& lhs, const Type& rhs);
-#endif
 #endif
 #if defined(BUILDING_LIBARDOUR) || defined(LIBARDOUR_IS_IN_WIN_STATIC_LIB)
 #include <ardour/msvc_libardour.h>
@@ -259,15 +251,6 @@ inline int64_t abs(int64_t val) throw()
 #endif
 #endif // __cplusplus
 
-#ifndef DEFAULT_COMPARISONS_DEFINED
-#define DEFAULT_COMPARISONS_DEFINED
-#define DECLARE_DEFAULT_COMPARISONS(Type) \
-	extern bool operator >  (const Type& lhs, const Type& rhs); \
-	extern bool operator <  (const Type& lhs, const Type& rhs); \
-	extern bool operator != (const Type& lhs, const Type& rhs); \
-	extern bool operator == (const Type& lhs, const Type& rhs);
-#endif
-
 #if !defined(LIBPBD_API) || defined(PBD_IS_IN_WIN_STATIC_LIB)
 // Emulate some C99 math functions which MSVC itself didn't
 // implement until later in life.