The specification for the Startup Notification Protocol (https://specifications.freedesktop.org/startup-notification-spec/startup-notification-latest.txt) says that we should put “StartupNotify=true” in our .desktop files if we support it.  Although we don’t cater for it directly, GTK gives us it for free from version 2.2 onwards (https://developer.gnome.org/platform-overview/stable/dev-launching-startupnotify.html.en).  Hence, we should advertise support provided that this is a GTK build.

I have attached a patch to do this.

The practical effect of this change is that window managers will arrange for a slow to start Emacs to not steal the keyboard focus of a user who is typing into another application when Emacs pops onto the screen.

I have requested copyright assignment paperwork but am currently waiting to hear back.

-- 
Peter Oliver