Comment 1 for bug 2003201

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/0.84.1ubuntu3 represents our split-out delta on
  top of old/debian (0.84.1)
* logical/0.85.0ubuntu1 represents our rebased delta on
  top of new/debian (0.85.0)
* merge/0.85.0ubuntu1 represents the re-worked delta based
  on several upstream patches

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

git range-diff --creation-factor=95 old/debian..logical/0.84.1ubuntu3 new/debian..merge/0.85.0ubuntu1

At this point, all elements of the delta are currently represented
by MRs in https://salsa.debian.org/debian/sbuild/-/merge_requests
and thus the merge is likely to become a sync at some point in the
future (many thanks to bdrung for all the upstreaming work).