[patch] Add baseline for SPARC64/Linux

[Eric Botcazou]

> 2019-02-20  Eric Botcazou  <ebotcazou@adacore.com>
> 
>         * configure.host (abi_baseline_pair): Adjust for SPARC64/Linux.
>         * config/abi/post/sparc64-linux-gnu: New directory.
>         * config/abi/post/sparc64-linux-gnu/baseline_symbols.txt: New file.
>         * config/abi/post/sparc64-linux-gnu/32: New directory.
>       * config/abi/post/sparc64-linux-gnu/32/baseline_symbols.txt: New file.

I can probably self-approve it as SPARC maintainer so now installed.

-- 
Eric Botcazou