Oh, and for what it's worth, I've also uploaded the (successful) build
log here:
https://people.debian.org/~anarcat/debian/jessie-lts/mercurial_3.1.2-2+deb8u5_amd64-2018-06-07T00:41:12Z.build
Warning: that is about 5MB of logs.
a.
--
The history of any one part of the earth, like the life of a soldier,
consists of long periods of boredom and short periods of terror.
- British geologist Derek V. Ager