https://devmanual.gentoo.org/ebuild-writing/users-and-groups/ says: "To add a user, use the enewuser function: enewuser <user> [uid] [shell] [homedir] [groups] [params] ... Finally, any data left over for the params argument is passed directly to useradd." 'params' arguments are not supported since: CVS revision 1.9 of user.eclass 2011-11-03 15:29:39 UTC "clean up enew{user,group} and drop the [extra] argument as no one is using it" https://sources.gentoo.org/cgi-bin/viewvc.cgi/gentoo-x86/eclass/user.eclass?view=log https://sources.gentoo.org/cgi-bin/viewvc.cgi/gentoo-x86/eclass/user.eclass?r1=1.8&r2=1.9&diff_format=u
Fixed in https://gitweb.gentoo.org/proj/devmanual.git/commit/?id=a47f823e94931580ffebcc76f160dc7dcf53e02b. Thanks!