Comment # 12 on bug 972787 from Egbert Eich

I've reworked sys.xsession and factored out all services to scriptlets which
live in /etc/X11/xdm/scripts. 
These scriptlets are ordered and should be sourced as they need to build a
command line which gets exec'ed.
I've taken Werner's latest suggestions for the gpg-agent scriptlet with minor
changes [*]. It was a bit tricky to detangle ssh-agent and gpg-agent, I had to
move the ssh-agent settings variables to a different scriptlet which gets run
before the gpg-agent one as the latter may modify the ssh settings.
I don't want to ship any of the script files in /etc/X11/xdm/scripts with xdm.
All these files should be moved to the package providing the respective
service.

You can find the modified xdm package in home:eeich:branches:X11:XOrg/xdm on
OBS.

[*] These have received only minimal testing and are only meant as a base line
for modifications.