due to FTBFS , node-proper-lockfile package will be removed in 5 days.
node-proper-lockfile currently has no dependents, but it will be required for
node-yarnpkg  (I plan to resume work on that  soon).
I have pushed the fix to the git repo on alioth. My DM process  is still
ongoing so please someone upload node-proper-lockfile 2.0.1-1 for me.