[libgo] Build fix for sparc-linux

[Ian Lance Taylor]

On Fri, Jan 16, 2015 at 12:37 PM, Richard Henderson <rth@redhat.com> wrote:
>
> The glibc setcontext modifies %g7, so the SETCONTEXT_CLOBBERS_TLS configure
> test triggers.
>
> My guess is that Solaris doesn't clobber %g7, or Rainer would have noticed this
> before.  Is it worth also checking for __linux__ in the elif test, or just wait
> until someone notices that they have an incompatible set of <ucontext.h>
> definitions?

Thanks, committed to mainline.

I agree with just committing it--let's see if anybody complains.

Ian