Sorry, this is not a libc-bin bug... But looking through the postinst scripts for the package's for both the ATI and nVidia drivers, it appears that for some reason when the script is executed, the script's in the 64-bit packages are skipping neumerous update-alternative lines, hence ldconfig isn't setting up the directories. So it appears to be the packages affected are fglrx, fglrx-updates, nvidia-173, nvidia-304, nvidia-310, & nvidia-313-updates, and possibly others.
Sorry, this is not a libc-bin bug... But looking through the postinst scripts for the package's for both the ATI and nVidia drivers, it appears that for some reason when the script is executed, the script's in the 64-bit packages are skipping neumerous update-alternative lines, hence ldconfig isn't setting up the directories. So it appears to be the packages affected are fglrx, fglrx-updates, nvidia-173, nvidia-304, nvidia-310, & nvidia-313-updates, and possibly others.