Release ebuilds have already been migrated to EAPI5 and distutils-r1, but live version have not. Please update it, here's the patch attached.
Created attachment 345328 [details, diff] Use distutils-r1 eclass and EAPI 5 in mercurial-9999
Created attachment 345330 [details, diff] Use distutils-r1 eclass and EAPI 5 in mercurial-9999 Oh blast. Quick fix: bring back forgotten docutils dep (asciidoc remains dropped, since it's not used anywhere in Mercurial sources and everything builds fine without it).
Commited, thanks.