It appears that this fix for bug 675870 has introduced a regression in form of inability to suspend an ongoing ebuild process.
I usually launch "sudo nice emerge @world" in some terminal and go on using machine as usual. When some heavy build coincides with some (mostly memory) heavy tasks I need to run, I just switch to the terminal running "emerge @world" and hit Ctrl+Z. This is no longer effective.
Steps to Reproduce:
1. Start some ebuild
2. Press Ctrl+Z during the compile phase
The build output to terminal stops, and shell reports job as suspended, however, in task monitor (e.g. htop) one can see that the child processes of pid-ns-init keep running in background.
Being able to suspend (and then resume) entire ebuild process tree.
*** Bug 777321 has been marked as a duplicate of this bug. ***
I'm not sure when, but this has been fixed. It was somewhere prior to 3.0.20