I see lib64 is gone from / and /usr in /var/lib/dpkg/info/libc6.list
... once I added the /lib64 -> /lib symlink back, things more or less
worked again.
I'm wondering if there was anything special you needed to do for this? I know after upgrading my system, that any commands other than bash's built-in commands are refusing to execute, giving me "no such file or directory errors".