Add an about button to the minimal sample for systems without menus.

On minimal ports like wxIOS no menus are available. Providing an about button allows at least a minimal user interaction in that case.

samples/minimal/minimal.cpp

@@ -164,6 +164,12 @@ MyFrame::MyFrame(const wxString& title)
 
     // ... and attach this menu bar to the frame
     SetMenuBar(menuBar);
+#else
+    // If menus are not available add a button to access the about box
+    wxSizer* sizer = new wxBoxSizer(wxHORIZONTAL);
+    wxButton* aboutBtn = new wxButton(this, wxID_ANY, "About...");
+    aboutBtn->Bind(wxEVT_BUTTON, &MyFrame::OnAbout, this);
+    sizer->Add(aboutBtn, wxSizerFlags().Center());
 #endif // wxUSE_MENUS
 
 #if wxUSE_STATUSBAR