Comment 1 for bug 2025652

Attaching patch against Debian unstable. For ease of review, relevant
commits and tags have been pushed to the following repository:

https://code.launchpad.net/~waveform/ubuntu/+source/sbuild/+git/sbuild

Specifically:

* logical/0.85.0ubuntu2 represents our split-out delta on
  top of old/debian (0.85.0)
* logical/0.85.2ubuntu1 represents our rebased delta on
  top of new/debian (0.85.2)
* merge/0.85.2ubuntu1 adds changelog and maintainer
  changes on top of logical/0.85.2ubuntu1

Hence, the following command may produce output useful to the purposes
of review:

git range-diff --creation-factor=100 old/debian..logical/0.85.0ubuntu2 new/debian..logical/0.85.2ubuntu1