[PATCH] revised fix for nanosleep check in GLIBCXX_ENABLE_LIBSTDCXX_TIME for darwin

[Jack Howarth]

On Tue, Oct 09, 2012 at 10:49:28AM -0700, Benjamin De Kosnik wrote:
> 
> > I don't like the sched_yield macro being set there because it's
> > detected correctly by configure anyway, but I'm not going to labour
> > that point any more.
> 
> Indeed. Then somebody will waste hours in the future wondering why
> configure says no but their TU says yes. 
 
    Since darwin has always supported nanosleep() and sched_yield() 
and the atypical behavior of the -enable-libstdcxx-time configure option
obviously confuses some end-users, it seems rational to just default to
--enable-libstdcxx-time=yes on for darwin. Is there another way to
achieve this short of defining both _GLIBCXX_USE_NANOSLEEP and
_GLIBCXX_USE_SCHED_YIELD in config/os/bsd/darwin/os_defines.h? If so,
I'll revise the patch to use that approach.
           Jack

> 
> At least a comment in the configure bits admitting defeat, people.
> 
> -benjamin