[PATCH, libstdc++] Add proper OpenBSD support

[Mark Kettenis]

> Date: Wed, 5 Sep 2012 10:55:27 +0300
> From: Jonathan Wakely <jwakely.gcc@gmail.com>
> 
> I'll look at this more carefully later today when I get back from a
> holiday, but it looks ok after a quick glance.

Great!

> I've CC'd gcc-patches, as required for all patches.

Sorry 'bout that.  Bit of a brain fart on my side; send it to
gcc-patches@openbsd.org instead of gcc-patches@gcc.gnu.org.