[gentoo-user] app-emulation/docker-20.10.2 ebuild is borked?

[Nikos Chantziaras <realnc@gmail.com>]

Portage was trying to update docker from 20.10.1 to 20.10.2. However, it 
aborts with:

   ERROR: setup
   CONFIG_RT_GROUP_SCHED:         is not set when it should be.

That's a stupid requirement and not needed, as it breaks realtime 
scheduling with rtkit (PulseAudio for example.)

So I copied the ebuild to my local overlay and removed ~RT_GROUP_SCHED 
from CONFIG_CHECK. Portage now aborts with:

   ERROR: compile
   ERROR: app-emulation/docker-20.10.2::local failed (compile phase):
     USE Flag 'selinux' not in IUSE for app-emulation/docker-20.10.2

OK, so I added "selinux" to IUSE. Portage now aborts with:

   Building: bundles/dynbinary-daemon/dockerd-dev
   GOOS="" GOARCH="" GOARM=""
   cannot find package "github.com/docker/docker/cmd/dockerd" in any of:
   /usr/lib/go/src/github.com/docker/docker/cmd/dockerd (from $GOROOT)
 
/var/tmp/portage/app-emulation/docker-20.10.2/work/docker-20.10.2/src/github.com/docker/docker/cmd/dockerd 
(from $GOPATH)
   * ERROR: app-emulation/docker-20.10.2::local failed (compile phase):
   *   dynbinary failed

Unfortunately, 20.10.1 was deleted from portage and I cannot go back as 
docker-cli has already been updated to 20.10.2...

Help?