Enable XDG-activation via launch context

Apply patch by :
https://github.com/dkondor

For reference : 
WayfireWM#293

Author: trigg

src/panel/widgets/menu.cpp

@@ -100,7 +100,8 @@ WfMenuMenuItem::WfMenuMenuItem(WayfireMenu *_menu, Glib::RefPtr<Gio::DesktopAppI
             action_obj->signal_activate().connect(
                 [this, action] (Glib::VariantBase vb)
             {
-                m_app_info->launch_action(action);
+                auto ctx = Gdk::Display::get_default()->get_app_launch_context();
+                m_app_info->launch_action(action, ctx);
                 menu->hide_menu();
             });
             m_menu->append_item(menu_item);
@@ -129,7 +130,8 @@ WfMenuMenuItem::WfMenuMenuItem(WayfireMenu *_menu, Glib::RefPtr<Gio::DesktopAppI
 
 void WfMenuMenuItem::on_click()
 {
-    m_app_info->launch(std::vector<Glib::RefPtr<Gio::File>>());
+    auto ctx = Gdk::Display::get_default()->get_app_launch_context();
+    m_app_info->launch(std::vector<Glib::RefPtr<Gio::File>>(), ctx);
     menu->hide_menu();
 }