When emerge does it's job, it creates locks inside PORTAGE_TMPDIR, one for the category and one for the package inside. On catbus.sparc.d.g.o, on the arch testing containers, two simultaneous emerge calls were done to emerge different versions of dev-lang/python, which needed to build dev-tcltk/blt dep. After some time I noticed that it is stuck and doesn't unblock, and when checking in htop output, I see that one of them is stuck in lock-helper.py over /var/tmp/portage/dev-tcltk while the other over /var/tmp/portage/dev-tcltk/blt. Checking the TMPDIR, I indeed saw /var/tmp/portage/.dev-tcltk.portage_lockfile and /var/tmp/portage/dev-tcltk/.blt-2.5.3-r1.portage_lockfile files.
