This seems to have gone away by itself (or by being fixed) sometime during March-April:

jani@saegusa:~$ grep -c xkmfile /var/log/Xorg.*
/var/log/Xorg.0.log:3
/var/log/Xorg.0.log.old:3
/var/log/Xorg.1.log:2
/var/log/Xorg.1.log.old:1507
/var/log/Xorg.2.log:2
/var/log/Xorg.2.log.old:2
/var/log/Xorg.3.log:2
/var/log/Xorg.failsafe.log:2
/var/log/Xorg.failsafe.log.old:2
jani@saegusa:~$ LC_ALL=C ls -lh /var/log/Xorg*
-rw-r–r– 1 root root 60K May 2 20:36 /var/log/Xorg.0.log
-rw-r–r– 1 root root 61K May 2 20:36 /var/log/Xorg.0.log.old
-rw-r–r– 1 root root 48K Apr 22 20:02 /var/log/Xorg.1.log
-rw-r–r– 1 root root 210K Mar 13 22:51 /var/log/Xorg.1.log.old
-rw-r–r– 1 root root 35K Jun 6 2011 /var/log/Xorg.2.log
-rw-r–r– 1 root root 33K Jun 6 2011 /var/log/Xorg.2.log.old
-rw-r–r– 1 root root 35K Jun 6 2011 /var/log/Xorg.3.log
-rw-r–r– 1 root root 32K Apr 29 17:22 /var/log/Xorg.failsafe.log
-rw-r–r– 1 root root 32K Apr 29 17:06 /var/log/Xorg.failsafe.log.old