overriding window icon

[Sergey Mironov]

Hi! Typical situation. X application doesn't have neither .desktop
icon, nor built-in window icon. There are lots of them and I have to
prepare the package for another one - zathura. Handling .desktop file
was easy - I've just added "Icon=<icon>" into zathura.desktop and
provided the icon under share/pixmaps. Now all the menu entries look
fine. But the window icon is still missing. Is there anything I can do
to set it without patching the sources? Does Xfce provide some icon
overriding mechanism?

Thanks in advance,
Sergey