Funnily enough something similar happened to me after doing a partial update. Doing a partial update are not supported in arch linux for this very reason.

sudo broke as well as many others command. ssh worked for a bit and then segfaulted. I edited my PATH to have a healthy version of libc but things kept breaking in different ways (version mismatches) In the end I had to use a live usb drive as I couldn't write to /usr/lib