GNUCash is opensource accounting software.
This requires slib, libofx, ORBit2, GConf, libtasn1, gnome-keyring,
gnome-mime-data, libbonobo, gnome-vfs, libgnomecanvas, libgnome, libbonoboui,
libgnomeui, libgnomecups, libgnomeprint, libgnomeprintui, gtkhtml, and goffice.
aqbanking is optional, but it's not available at SlackBuilds.org.
Building the deps in the order listed above should give the desired results.