Enable -Werror for the reproducible builds, leave it off for the rest. That should solve most of it. The biggest and rather frustrating issue left is that warn

Enable -Werror for the reproducible builds, leave it off for the rest. That should solve most of it. The biggest and rather frustrating issue left is that warnings are heavily tool depended, not just in that new tools will produce new warnings, but in that different tools will produce incompatible warning. The workaround that makes the warning go away in one tool, will create a warning in the other. You can end up with a lengthy back&forth before you find something that makes all the tools happy and you frequently run into situation were you are really just pleasing the tools, not fixing any actual issues.