Comment 14 for bug 309674

It's just the opposite of a trap; it's a further safety measure. It arranges that, *even if* an autotools update is accidentally run, then everything will still work. The intention is not that an autotools update *should* be run - I agree that that is often risky - but to provide insurance in case it is.

In the event that an autotools update is not run, the debian/rules change has no effect.