The gnome-terminal-2.1.0.ebuild in Portage is broken in regard to vte. It has vte as an runtime dependency but doesn't build against vte. Reason: a typo. --with-widget=vzvt should propably be --with-widget=vte otherwise it is build against the old libzvt.
I know, it sais somewhere 'you can change vte for zvt'. I decided to go for zvt because vte is still too unstable imo, but i added it so people can test if they want. The extra z is a typo, but it still has the desired effect.
