Comment 2 for bug 663156

So I'm marking this as incomplete for now; I think the request would be valid if we had a concrete case of a need for this feature, but I'd rather not add such an option unless an use case requires it. Package build tools typically permit this kind of things (e.g. pbuilder and sbuild) but sbuild defaults to stripping off the environment, and you don't control the environment of packages which get autobuilt.