Translated man pages (like /usr/share/man/ru/man1/login.1.bz2) are usually outdated, thus many people prefer to avoid installing them. It probably makes sense to move man pages from sys-apps/shadow to shadow-man or man-pages package to make it possible to independently control "nls" USE flag (or related linguas_XX flags) for binaries and man pages of sys-apps/shadow.
should be all set now in the tree; thanks for the report! Commit message: Respect LINGUAS when installing man pages http://sources.gentoo.org/sys-apps/shadow/shadow-4.2.1-r1.ebuild?rev=1.1
shouldn't be using IUSE_EXPAND for this, just look at the LINGUAS env var that is kept around for such purposes, like every gettext/intltool package does out of the box, without littering the USE flags. In fact, upstream should really have it work automatically. Additionally this completely loses the notion of "install all translations when LINGUAS is unset", that it should have.
(In reply to Mart Raudsepp from comment #2) that's a bug for portage/PMS. LINGUAS is not in the binpkg metadata whereas IUSE is, and the whole point of linguas_xx is to see if a particular lang is enabled. the compiled/installed behavior should only be changing based on USE, not other random untracked env vars.
