Gets the built-in image for this icon, if any. To allow
GTK+ to use built in icon images, you must pass the
GTK_ICON_LOOKUP_USE_BUILTIN to
gtk_icon_theme_lookup_icon().
Since 2.4
the built-in image pixbuf, or NULL. No extra reference is added to the returned pixbuf, so if you want to keep it around, you must use g_object_ref(). The returned image must not be modified. [transfer none]
Gets the built-in image for this icon, if any. To allow GTK+ to use built in icon images, you must pass the GTK_ICON_LOOKUP_USE_BUILTIN to gtk_icon_theme_lookup_icon(). Since 2.4