Remove (Open)Watcom support.

This compiler is not being developed since several years and almost certainly
can't be used to build the current wxWidgets sources anyhow, so remove all
support for it, including a lot of extremely ugly workarounds for its bugs
with template functions.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@76546 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/window.h

@@ -886,9 +886,6 @@ public:
     virtual void SetPreviousHandler(wxEvtHandler *handler) wxOVERRIDE;
 
 
-    // Watcom doesn't allow reducing access with using access declaration, see
-    // #10749
-#ifndef __WATCOMC__
 protected:
 
     // NOTE: we change the access specifier of the following wxEvtHandler functions
@@ -909,7 +906,6 @@ protected:
     using wxEvtHandler::ProcessPendingEvents;
     using wxEvtHandler::AddPendingEvent;
     using wxEvtHandler::QueueEvent;
-#endif // __WATCOMC__
 
 public: