sftp support in net-libs/libssh is optional, but required by xbmc for sftp. Currently xbmc only debends on the presence of net-libs/libssh, but not on the sftp use flag.
should be all set now in the tree; thanks for the report! Commit message: Require USE=sftp be set in libssh when we pull it in http://sources.gentoo.org/media-tv/xbmc/xbmc-12.1-r1.ebuild?r1=1.4&r2=1.5 http://sources.gentoo.org/media-tv/xbmc/xbmc-12.2-r1.ebuild?r1=1.6&r2=1.7 http://sources.gentoo.org/media-tv/xbmc/xbmc-9999.ebuild?r1=1.150&r2=1.151
