See attached build log.
(Please do not complain about the need for looking at the build log until you can provide an easy way to open bugs with the correct data picked out of a tinderbox log. Thanks.)
Created attachment 242211 [details]
Should be fixed with x11-drivers/xf86-input-virtualbox-4.0.0
Still not fixed... reopening.
Package is no longer in the tree. Closing.