https://blogs.gentoo.org/ago/2020/07/04/gentoo-tinderbox/ Issue: net-mail/b4-0.7.2 uses a probably incorrect DISTUTILS_USE_SETUPTOOLS value. Discovered on: amd64 (internal ref: tinderbox)
Created attachment 734347 [details] build.log build log and emerge --info
ci has reproduced this issue with version 0.8.0 - Updating summary.
Mass-closing as this is now obsoleted by PEP517 mode.