/etc/X11/xdm/Xsetup_0 seems to be the default one that came with X . The section marked: # --- Gentoo --- (and below) is no longer there. Is that intentional? Also /etc/pam.d/{xdm,xserver} have lost their specific library locations. etc.
This is all intentional. The PAM paths are unnecessary and break 64-bit systems. The KDE-specific code in Xsetup_0 is no longer used, so it made sense to stop having a custom file. I'm just going to pick one of those two to mark this a duplicate of. Thanks for being so observant. One of these times I'm sure a bad change will slip through. =) *** This bug has been marked as a duplicate of 80225 ***