You're pretty negative on this idea, aren't you? Let me whittle away at it a bit before we reject it as impractical.
Sure, have fun.
I've used -Wall -Werror with success in the past with a medium-sized code base, and used it as a stick to keep people from checking in dodgy code. So it's not that it's always impractical. The issue I have is that a distributed development environment makes it hard, as does maintaining a portable code base linked against many possible versions of libraries. If a commit doesn't break on Alexandre's box, and it gets committed, but it does break on some other machine, what then? Who fixes it?
I think that individually, we can turn it on from time to time to see what pops up, just like running with valgrind. But forcing everyone to run with it seems draconian. --Juan