Created attachment 516702 [details, diff] toolchain-binutils-tar-xz-snapshot.patch As of the binutils-2.29.1 snapshot, the primary archive format is ".tar.xz". Please apply the attached patch, so that recent snaphots can be supported by the eclass.
toolchain-binutils is not used in new binutils ebuilds. You'll need to specify snapshot name in ebuild directly. binutils-9999 seem to use *.xz suffix.