I have just installed gintro 0.8.1 on my Gentoo Linux again without problems.
I am using gtk+-3.24.22. Gtk+-3.24 should have a stable API, so I would not really expect problems. Maybe it is indeed your new vte 0.62.0-1 Unfortunately for Gentoo it is not yet available from the package management system. <https://packages.gentoo.org/packages/x11-libs/vte> I will see if I can push gentoo maintainers to make 0.62 available or if I can install it from sources. Exotic packages like vte and gstreamer generate generally much more trouble than the gtk core packages as they are developed not by GTK core devs and are used by only few people.