[gold][patch] Pass the output filename to the plugin

[Cary Coutant]

> gold/
> 2010-06-01  Rafael Espindola  <espindola@google.com>
>
>        * plugin.cc (Plugin::load): Pass the output name to the plugin.
>
> include/
> 2010-06-01  Rafael Espindola  <espindola@google.com>
>
>        * plugin-api.h (ld_plugin_tag): Add LDPT_OUTPUT_NAME.

Looks good to me.

-cary