Don't crash under XP in the taskbar button sample.

Refuse to run if the taskbar button API is not available.

This wouldn't make much sense anyhow and is the simplest thing to do.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@77703 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

samples/taskbarbutton/taskbarbutton.cpp

@@ -193,6 +193,12 @@ bool MyApp::OnInit()
     }
 
     MyFrame *frame = new MyFrame("wxTaskBarButton App");
+    if ( !frame->MSWGetTaskBarButton() )
+    {
+        wxLogError("Task bar button API is not available on this system, sorry.");
+        return false;
+    }
+
     frame->Show(true);
 
     return true;