Thanks for the heads-up, frushiyama. WordPress's syntax highlighter can sometimes be a nuisance.

glibc rebuilt with new updates, and X also updated.
the X server now start and i can see the screen but the keyborad and the mouse are dead
the nunlk light were on when i was without X, and when the X started the led goes off.
here is my complete /var/log/Xorg.0.log :
http://pastebin.com/CSn4wuCs

Well, this thread has strayed pretty far from the original topic, so I'll throw my two-cents in.

It appears to me that the core X server and some of its modules have gotten out-of-sync. For example, I use the "dummy" video driver. I use an NTSC television, not HDMI, and a GUI is nearly impossible to read on it. By skipping the X framebuffer, I can also specify "gpu_mem=8" in /boot/config.txt. (Yes, the stated minimum is 16, but it Works For Me.) If I want to use a full GUI on the RPi, I can use remote XDMCP from my desktop.

When the RPi XDM stopped launching the X server, I saw the same error in /var/log/xdm.err that frushiyama had, with the first (EE) line appearing right after trying to load GLX. However, examining the more complete /var/log/Xorg.0.log showed that the (EE) line occurred right after trying to activate the video driver, "dummy" in my case. I think that's where the ABI difference was occurring.

And, since the "dummy" driver didn't get rebuilt, I still get the ABI mismatch message, and no X session started on the RPi. (But XDMCP works OK. Go figure.)

How would I go about re-building just the "dummy" module? There's no way I can re-build all of X on my RPi in this lifetime. :)

Well it's broken in -current so I'll fix it. I'm going to rebuild all of the 'drivers' modules.

You should be able to build an individual package in almost the same way as for x86, apart from you need to use 'arm/build' instead of ./x11.SlackBuild

The general driver re-build got my X server (with the "dummy" video driver) back up and running. Thanks, drmozes.

Mine too, but i use hdmi :) .