What is broken by the change, which is indicated by this message, is the ability to control foreground jobs (e.g., ctrl+c) from the terminal after logging in from sux.
su, gksu and others are not affected by the change, and can still control and terminate hang-up jobs running in the foreground by doing job control key combinations in the terminal.
To demonstrate:
$ su
Passsword: (enter root password)
# cat /dev/zero > /dev/null
(terminal hangs, ctrl+c to kill the job)
$ sux
Passsword: (enter root password)
# cat /dev/zero > /dev/null
(terminal hangs, ctrl+c ends the session with:
Session terminated, terminating shell...^C
but the job is left running. kill the job from another terminal)
quoted from
here:
This needs to be investigated further (in particular to check what sux is
doing, and whether this could be fixed on the sux side).
(The fix removes the controlling terminal for non-interactive executions)