If I add PORTDIR="/usr/portage" to /etc/portage/make.conf, euses works properly. But if I remove this line, euses doesn't work:
$ euses vdpau
PORTDIR not found
app-portage/euses-2.5.9 cannot obtain $PORTDIR from portageq. But $PORTDIR in make.conf is obsolete and deprecated.
This bug also blocks bug https://bugs.gentoo.org/662982
Any progress here?
euses checks for an environment variable PORTDIR. Does this help?