[gold patch] PR gold/12163: Don't load same archive twice as a whole archive

[Cary Coutant]

>>       PR gold/12163
>>       * gold/archive.cc (Archive::Archive): Initialize new data member.
>>       (Archive::include_all_members): Return if archive has already been
>>       included.
>>       * gold/archive.h (Archive::include_all_members_): New data member.
>
> This is OK.

Thanks, committed.

-cary