update default OS for debugging on darwin

[Mike Stump]

On Feb 7, 2011, at 5:30 PM, Jack Howarth wrote:
>   Speaking of OS versions, can you take a look again at...
> 
> http://gcc.gnu.org/ml/gcc-patches/2010-08/msg01703.html

> I think it is long past time to start moving the ancient darwin
> releases into the unsupported target list. Again, that second hunk
> removes  *-darwin1[0-9]* from the powerpc-*-darwin* case since
> darwin10 was never released for powerpc.

But I run ppc on darwin10...  :-(  I would have to think about this, which if the patch is supposed to save me from from thinking about older system, is counter productive.  So, I'd propose I not think about this and we leave things as is.  We aren't saving much by adding a line to error out.