Bug#200699:

[Matt Swift]

Here is an idea for /etc/logrotate.d/xdm:

# Logrotate file for xdm.log

# The log file is named in /etc/X11/xdm/xdm-config.  How to extract it here?
# DisplayManager.errorLogFile:  /var/log/xdm.log
#
# Better include a warning in a comment in /etc/X11/xdm/xdm-config that the log
# file name is assumed here.

# These defaults in /etc/logrotate.conf:
# weekly
# rotate 4
# create

/var/log/xdm.log {
        notifempty
        missingok
}