void gtk_icon_source_set_direction ( GtkIconSource* source, GtkTextDirection direction )
Sets the text direction this icon source is intended to be used with.
Setting the text direction on an icon source makes no difference
if the text direction is wildcarded. Therefore, you should usually
gtk_icon_source_set_direction_wildcarded() to un-wildcard it
in addition to calling this function.
Text direction this source applies to.