Hello I would know what finally occurred with: http://www.mail-archive.com/gentoo-dev@lists.gentoo.org/msg31489.html
Seems that last comment was: http://www.mail-archive.com/gentoo-dev@lists.gentoo.org/msg31502.html and, after that, activity stopped Is there any problem for having this "USE cleanup" done? Thanks a lot for the information :-)