[gdm-list] 3.2.1.1: How to start gdm-simple-greeter?

[tjoen <tjoen dds nl>]

How to start gdm-simple greeter, the intended way
gdm-3.2.1.1
System: LFS-like, trying to build Gnome-3.2.2

After starting gdm, gdm-shell.session exits and
gdm-fallback.session starts with gnome-panel
In upper right corner I can see that it is run by user gdm.
But no gdm-simple greeter.
$ ps ax
..
 4474 ?    Ssl 0:00 /usr/sbin/gdm-binary
 4477 ?    Sl  0:00 /usr/libexec/gdm-simple-slave --display-id /org/gnom
 4479 tty7 Ss+ 0:00 /usr/bin/Xorg :0 -br -verbose -logverbose 7 -auth /v
 4496 ?    Ss  0:00 /usr/bin/dbus-daemon --fork --print-pid 5 --print-ad
 4497 ?    Sl  0:00 gdm-session-worker [pam/gdm-welcome]
 4499 ?    Sl  0:00 /usr/libexec/accounts-daemon
 4503 ?    Ssl 0:00 /usr/bin/gnome-session -f --debug
 4510 ?    Sl  0:00 /usr/libexec/gnome-settings-daemon
 4516 ?    S   0:00 /usr/libexec/gvfsd
 4519 ?    Sl  0:00 metacity
 4523 ?    S   0:00 /usr/libexec/gconfd-2
 4524 ?    Rl  0:01 gnome-panel
 4526 ?    Sl  0:00 /usr/libexec/dconf-service
 4532 ?    Sl  0:00 /usr/libexec/notification-daemon
 4538 ?    S   0:00 /usr/libexec/gvfs-gphoto2-volume-monitor
 4540 ?    Sl  0:00 /usr/libexec/wnck-applet
 4542 ?    Rl  0:00 /usr/libexec/clock-applet
 4544 ?    S   0:00 /usr/libexec/mission-control-5
 4546 ?    Sl  0:00 /usr/libexec/notification-area-applet
 4558 ?    Sl  0:00 /usr/bin/gnome-keyring-daemon --start --foreground -

$ grep greeter /var/log/gdm\:0-greeter.log
gnome-session[5114]: DEBUG(+): fill: *** Looking 
if /usr/share/gdm/greeter/gnome-session/sessions/gnome.session is a 
valid session file
gnome-session[5114]: DEBUG(+): Cannot use session 
'/usr/share/gdm/greeter/gnome-session/sessions/gnome.session': 
non-existing or invalid file.
gnome-session[5114]: DEBUG(+): fill: *** Looking 
if /usr/share/gdm/greeter/gnome-session/sessions/gnome-fallback.session 
is a valid session file
gnome-session[5114]: DEBUG(+): Cannot use session 
'/usr/share/gdm/greeter/gnome-session/sessions/gnome-fallback.session': 
non-existing or invalid file.
gnome-session[5114]: DEBUG(+): GsmUtil: Looking in 
'/usr/share/gdm/greeter/gnome/autostart'
gnome-session[5114]: DEBUG(+): GsmUtil: Looking in 
'/usr/share/gdm/greeter/applications'
gnome-session[5114]: DEBUG(+): GsmUtil: Looking in 
'/usr/share/gdm/greeter/gnome/autostart'
gnome-session[5114]: DEBUG(+): GsmUtil: Looking in 
'/usr/share/gdm/greeter/applications'
gnome-session[5114]: DEBUG(+): GsmUtil: Looking in 
'/usr/share/gdm/greeter/gnome/autostart'
gnome-session[5114]: DEBUG(+): GsmUtil: Looking in 
'/usr/share/gdm/greeter/applications'
gnome-session[5114]: DEBUG(+): GsmUtil: Looking in 
'/usr/share/gdm/greeter/gnome/autostart'
gnome-session[5114]: DEBUG(+): GsmUtil: Looking in 
'/usr/share/gdm/greeter/applications'
gnome-session[5114]: DEBUG(+): GsmUtil: Looking in 
'/usr/share/gdm/greeter/gnome/autostart'
gnome-session[5114]: DEBUG(+): GsmUtil: Looking in 
'/usr/share/gdm/greeter/applications'
gnome-session[5114]: DEBUG(+): GsmUtil: Looking in 
'/usr/share/gdm/greeter/gnome/autostart'
gnome-session[5114]: DEBUG(+): GsmUtil: Looking in 
'/usr/share/gdm/greeter/applications'
gnome-session[5114]: DEBUG(+): GsmUtil: Looking in 
'/usr/share/gdm/greeter/gnome/autostart'
gnome-session[5114]: DEBUG(+): GsmUtil: Looking in 
'/usr/share/gdm/greeter/applications'
gnome-session[5114]: DEBUG(+): GsmUtil: Looking in 
'/usr/share/gdm/greeter/gnome/autostart'
gnome-session[5114]: DEBUG(+): GsmUtil: Looking in 
'/usr/share/gdm/greeter/applications'

No gdm-simple-greeter at all.

With
/etc/X11/sessions/gnome.desktop:
[Desktop Entry]
Exec=custom

and /var/lib/gdm/.xsession:
exec /usr/libexec/gdm-simple-greeter
doesn't work

Replacing shell /sbin/nologin by /bin/bash in
/etc/passwd lets me start xterm from panel-menu
There I can start /usr/libexec/gdm-simple-greeter
to login as a normal user.

I think I am doing something wrong but what?
gdm-3.0.0 did work in the past