[patch] Add baseline for SPARC64/Linux

[Eric Botcazou]

> Sorry for the delay, I'm in a meeting all week with limited time for
> patch review.

No problem, thanks for reviewing!

> We don't usually include the __once_callable symbols in the baseline
> file, are you sure it's correct to do so for sparc64-linux-gnu?
> 
> +TLS:8:_ZSt11__once_call@@GLIBCXX_3.4.11
> +TLS:8:_ZSt15__once_callable@@GLIBCXX_3.4.11

Now removed for the sake of consistency with the SPARC/Linux twin port.

-- 
Eric Botcazou