As of the most recent versions of udev, the udev rules should be installed in /lib/udev on all systems, not /$(get_libdir)/udev.
feel free to apply necessary changes :)
+ 13 Jul 2011; Pacho Ramos <pacho@gentoo.org> libgphoto2-2.4.11.ebuild: + Fix udev location rules, bug #374989 by Jonathan Callen. +