Add unwind information to i386 LinuxThreads syscalls

[Nix]

On Sun, 13 Mar 2005, Daniel Jacobowitz stipulated:
> [BTW, LinuxThreads doesn't build on i386 --with-__thread any more.  If
> that's an unsupported configuration, can configure complain about it?
> Undefined references to _res.]

This is bug #674. I did a bit of crude investigating of this in that
bug's comments; I'm unclear about the right way to fix it, though.

-- 
> ...Hires Root Beer...
What we need these days is a stable, fast, anti-aliased root beer
with dynamic shading. Not that you can let just anybody have root.
 --- John M. Ford