14.04.5 startx and xinit do not start from command line

[DLCBurggraaff]

After upgrading Xubuntu 14.04.4 to 14.04.5 startx and xinit no longer start from command line. E.g.:
-- <Ctrl+Alt+F2>
-- login
-- startx -- :1
gives
[ 43.309] (EE)
Fatal server error:
[ 43.309] (EE) parse_vt_settings: Cannot open /dev/tty0 (No such file or directory)
[ 43.309] (EE)
[ 43.309] (EE)
Please consult the The X.Org Foundation support
  at http://wiki.x.org
 for help.
[ 43.309] (EE) Please also check the log file at "/home/burdi01/.local/share/xorg/Xorg.1.log" for additional information.
[ 43.309] (EE)

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: xinit 1.3.2-1
ProcVersionSignature: Ubuntu 4.4.0-31.50~14.04.1-generic 4.4.13
Uname: Linux 4.4.0-31-generic x86_64
ApportVersion: 2.14.1-0ubuntu3.21
Architecture: amd64
CurrentDesktop: XFCE
Date: Fri Aug 5 12:37:53 2016
SourcePackage: xinit
UpgradeStatus: No upgrade log present (probably fresh install)

[DLCBurggraaff (burdi)]

One additional observation:
-- <Ctrl+Alt+f2> ; login as root ; startx -- :1 succeeds
whereas
-- <Ctrl+Alt+f2> ; login as burdi01 ; startx -- :1 fails
:D

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.