Restore wxEVT_MENU_CLOSE generation under Windows 95 after r70151.

WM_UNINITMENUPOPUP is "only" available since Windows 98/2000 so restore the
old code using WM_EXITMENULOOP as fall back, just to avoid any regressions for
people who might still be using these systems.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@70156 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/msw/frame.h

@@ -132,9 +132,18 @@ protected:
     // wxMDIChildFrame
     bool MSWDoTranslateMessage(wxFrame *frame, WXMSG *msg);
 
+#if wxUSE_MENUS
+    // handle WM_EXITMENULOOP message for Win95 only
+    bool HandleExitMenuLoop(WXWORD isPopup);
+
     // handle WM_(UN)INITMENUPOPUP message to generate wxEVT_MENU_OPEN/CLOSE
     bool HandleMenuPopup(wxEventType evtType, WXHMENU hMenu);
 
+    // Command part of HandleMenuPopup() and HandleExitMenuLoop().
+    bool DoSendMenuOpenCloseEvent(wxEventType evtType, wxMenu* menu, bool popup);
+#endif // wxUSE_MENUS
+
+
     virtual bool IsMDIChild() const { return false; }
 
     // get default (wxWidgets) icon for the frame