Hello, I found a workaround for this: create a symlink for libudev.so.0 leading to libudev.so in /usr/lib.
No, that's not it, I have two almost identical installs: one for my laptop, one at home for the desktop. On the latter, I moved the forementioned code from rc.lua into .xinitrc ,otherwise everything is the same. Also, I just tried the default rc.lua and it does not help. The issue must therefore lie elsewhere.