Idea for smoother upgrade from pre-4.3 XFree to 4.3
To get correctly configured russian keyboard In pre-4.3 xkb configuration,
we had to write
Option "XkbLayout" "ru"
In 4.3, we have to write
Option "XkbLayout" "us,ru"
because setting it to just "ru" now gives only russian letters input,
instead of both english and russian (which is basically required).
I guess the same situation may be with other languages also.
The upgrade from pre-4.3 versions of xserver-xfree86 package will be
smoother, if the upgrade scripts will change the xkb settings to new
style automatically. Or at least warn the user that he needs the change.