With the virtual/libusb migration, app-misc/rioutil should now depend on virtual/libusb:0 if possible. See tracker bug 270039 for more information.
+ 28 Jun 2009; Patrick Lauer <patrick@gentoo.org> rioutil-1.5.0-r1.ebuild: + EAPI2ification, nailing libusb dep to slot 0, fixes #270158