Gold Linker Patch: Introduce the "retpoline" x86 mitigation technique for variant #2 of the speculative execution vulnerabilities disclosed today, specifically identified by CVE-2017-5715 and in some places called "spectre".

[Cary Coutant]

>       * One other pain point is we do have internally is we use a
> configuration for tests where we build a number of shared objects and
> keep the main binary pretty thin.  We have explicitly disabled now
> binding for this due to performance reasons, huge increase in the
> number of dynamic relocations putting unacceptable overheads on our
> distributed build system.  We need to find a solution here.

Why do unittests need to be fully secured from attack?

-cary