[PATCH v2 9/9] ld: Add glibc dependency for DT_RELR

[Florian Weimer]

* H. J. Lu via Binutils:

> +  const char *relr = "GLIBC_ABI_DT_RELR";

This needs to be in the implementation namespace, otherwise the user can
provide their own symbol, effectively breaking the lockout.

Thanks,
Florian