Until version 1.6.0 man pages was provided in the tarball (and we were using them despite our guildelines prefer we generate everything from sources)
Since version 1.6.1 we have to generate them, fine.
But:
$ make man
mkdir -p doc/man
/usr/bin/sphinx-build -qEW -b man ./doc doc/man
Warning, treated as error:
WARNING: intersphinx inventory 'http://mongoc.org/libbson/current/objects.inv' not fetchable due to <class 'requests.exceptions.HTTPError'>: 404 Client Error: Not Found for url: http://mongoc.org/libbson/current/objects.inv
Trivial fix:
sed -e 's|http://mongoc.org/libbson/current|../src/libbson/doc/html|' \
-i doc/conf.py