net-misc/rsync-3.0.2 uses iconv when automagically detected. This 1) should probably be --disable/enable-iconv in the ebuild, and 2) as I think iconv is useful for rsync, it should depend on virtual/libiconv. I suggest virtual/libiconv in DEPEND and --enable-iconv in econf call.
we're not hardcoding dependencies on iconv ... we have USE=iconv; leverage it http://sources.gentoo.org/net-misc/rsync/rsync-3.0.2.ebuild?r1=1.5&r2=1.6