gnuconfig.eclass is declared DEAD, but toolchain.eclass and toolchain-binutils.eclass use it by calling gnuconfig_update. gnuconfig.eclass currently doesn't include "/usr/share/automake-1.10/config.sub" in gnuconfig_findnewest().
@Fabian: Forgot to assign it? :)
it's considered dead for most people, not all
also, the automake/libtool search list really doesnt matter considering all the ebuilds hard depend on gnuconfig and symlink their internal files to it