I did an emerge -e world, and it blocked on app-misc/dnetc-2.9008.490, waiting
for me to supply interactive configuration input. (It wanted me to enter my
email address, as if I'd typed "dnetc -config") This cost me a few hours of
compiling time.
Of course, Gentoo ebuilds are not supposed to do that. A long emerge should be
able to run to error or completion unattended.
My email address was already in /etc/conf.d/dnetc, anyway.
I think the pkg_preinst step that calls "/opt/distributed.net/dnetc -quiet
-flush" is the problem. dnetc is being too "smart" and implicitly doing
-config even though that option wasn't given. Maybe this step should be
removed, and a comment asking the user to do it himself added?