work around Borland compilation errors

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@56461 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/common/event.cpp

@@ -561,7 +561,10 @@ wxMouseEvent::wxMouseEvent(wxEventType commandType)
 void wxMouseEvent::Assign(const wxMouseEvent& event)
 {
     wxEvent::operator=(event);
-    wxMouseState::operator=(event);
+
+    // Borland C++ 5.82 doesn't compile an explicit call to an implicitly
+    // defined operator=() so need to do it this way:
+    *static_cast<wxMouseState *>(this) = event;
 
     m_x = event.m_x;
     m_y = event.m_y;