rtld-elf - Don't pass -elf to the linker

rtld-elf - Don't pass -elf to the linker

* Don't pass -elf to the linker, only our binutils217 understands it.
  All others interpret it as using the symbol 'lf' as entry point. We
  didn't have a problem so far because the regular ld (bfd) falls back
  to a reasonable entry point (start of .text), but gold doesn't and
  falls back to 0.

* This enables us to run world linked with gold.