[patch] Default to --enable-libstdcxx-time=auto

[Benjamin De Kosnik]

> Looks good to me.  

Great, trunk patch in.

> Will you prepare corresponding patch for the 4.8
> branch too (I guess it should be pretty much the same, not sure if it
> should keep using typedef system_clock steady_clock as before for the
> non-MONOTONIC configuration, or if it should just do the same thing
> as trunk)?

Same thing, I think. Testing now, ok when it completes?

-benjamin