- due to the change to the rDNS-based filename some window managers like
Cinnamon can't find the according desktop file for scummvm's
application window anymore
- this causes some unwanted behavior (e.g. not using the correct icons
in the task switcher)
- before commit f683b9b916a730d93defcd12522205633588059b the mapping
worked by matching the WM_CLASS property of the scummvm window to
the filename of the desktop file
- this patch sets the StartupWMClass property in the .desktop file to
the name of scummvm's WM_CLASS X property which will allow a proper
mapping
- the WM_CLASS property is set by SDL to the base name of ScummVM binary.