It looks like Thomas Tanner has uploaded some more recent packages which has sorted the symlink issue out, many thanks.

I'm just rebuilding Octave without the runtime texinfo requirement (hopefully, I can't remember why that was needed in the first place) and am optifying it, so it should soon be in Extras-devel

I'm also planning on building this (for want of any better suggestions): http://cberger.net/Programs/Kalculus.html which can act as a UI for both Octave and Yacas. Then I guess we should push the whole lot to Extras.