diff --git a/include/wx/os2/private.h b/include/wx/os2/private.h
index 02a11b3ac5..d0773e6e6a 100644
--- a/include/wx/os2/private.h
+++ b/include/wx/os2/private.h
@@ -286,7 +286,7 @@ extern HBITMAP wxInvertMask(HBITMAP hbmpMask, int w = 0, int h = 0);
 // global data
 // ---------------------------------------------------------------------------
 
-#ifdef __WXOS2__
+#ifdef __WXPM__
 // The MakeProcInstance version of the function wxSubclassedGenericControlProc
 WXDLLEXPORT_DATA(extern int) wxGenericControlSubClassProc;
 WXDLLEXPORT_DATA(extern wxChar*) wxBuffer;
@@ -297,7 +297,7 @@ WXDLLEXPORT_DATA(extern HINSTANCE) wxhInstance;
 // global functions
 // ---------------------------------------------------------------------------
 
-#ifdef __WXOS2__
+#ifdef __WXPM__
 extern "C"
 {
 WXDLLEXPORT HINSTANCE wxGetInstance();
diff --git a/include/wx/platform.h b/include/wx/platform.h
index 7dd47e6e0f..f91591ed01 100644
--- a/include/wx/platform.h
+++ b/include/wx/platform.h
@@ -400,10 +400,7 @@
 #elif defined(__OS2__)
 
     /* wxOS2 vs. non wxOS2 ports on OS2 platform */
-#    ifndef __WXMOTIF__
-#        ifndef __WXOS2__
-#            define __WXOS2__
-#        endif
+#    if !defined(__WXMOTIF__) && !defined(__WXGTK__) && !defined(__WXX11__)
 #        ifndef __WXPM__
 #            define __WXPM__
 #        endif