libssp is one of the GNU removal show stoppers: it is used for stack
protection but it is fundamentally a compiler library.
Checking r333398 and r333399 have dropped the requirement to build rtld
with an SSP-enabled libc. Setting libssp along with the other gcclibs
should make things clearer now.
I am not an expert on the build. Hopefully this is enough to stop libssp
from building when we are not using the GNU toolchain?