Special keys act incorrectly after update

[k4be]

Many of the keys started to behave incorrect:
Right Alt acts as left arrow.
Up arrow acts as printscreen.
Down arrow acts as enter.
Pause acts as home.
There is no repeating for the special keys - holding 'delete' indefinitely will erase only one character - but alphanumeric keys work normally.
Everything works correctly on console, the problem appears in X (Gnome), the keys are incorrect also inside the virtualbox guest os.
Some packages (can't exactly tell, which ones) were recently updated, and i think it caused the problem.

[VoidMage]

'scuse me, but what rock have you been under for the last year or so ?

Or is this another of "a few years have passed, so I decided to sync again" problems ?

OK, having said that, I switch back to "reasonably reasonable" mode.

That sounds just like the very old problem people had when they've been passing 'XkbRules "base"' to xserver, while using evdev driver, which works only with 'XkbRules "evdev"' (no need to pass it - driver hardcodes it).
Check your xorg.conf and your custom files.

[k4be]

Many of system libraries were updated some month ago (with revdep-rebuild), and it didn't break anything.
Part of X logfile:

[VoidMage]

At first glance, yes, but there are all those little things - pastebin your xorg.conf and check if you aren't i.e. playing with 'setxkbmap' somewhere.

If you're using Gnome, check if its keyboard applet isn't messing things up behind your back (should be set to something like "evdev managed", if at all).