PATCH: Fix linker plugin support for gnu linker

[Ian Lance Taylor]

Cary Coutant <ccoutant@google.com> writes:

> I'm still not convinced that the new plugin API is necessary -- simply
> adding the extra pass-through libraries as needed would fix the
> problem. In either case, a gcc driver change is still necessary. That
> by itself would fix both linkers with the 1-stage approach, with no
> changes to either linker.

To be clear, with my proposed patch, a gcc driver change is not
required, although a similar patch could be made via a driver change.

Ian