Erreur de compilation Discourse : « Une erreur s'est produite lors de l'installation de rbtrace (0.5.1), et Bundler ne peut pas continuer

I usually avoid it like the plague, especially with cloud VM’s where I only get an SSH connection… if anything happens, it is restore from backup.

EDIT: I updated to Ubuntu 18 (from 17) and now it builds correctly. So I suppose this definitely has something to do with old O/S versions…