[v3] libstdc++/49745 (review required for the gthr-posix.h changes)

[Jason Merrill]

On 07/15/2011 08:47 AM, Paolo Carlini wrote:
> The patch should be in general quite conservative and safe, in
> particular, the gthr-posix.h changes, which I cannot approve myself,
> touch bits only used by libstdc++-v3 + the macro avoiding the
> unconditional inclusion of <unistd.h>, which, according to Jakub's
> analysis, should be required only by objc.

I'm a little uncomfortable with defining a macro in libstdc++ to be used 
by the gthr files in gcc.  I would lean more toward a gthr-posix-conf.h 
generated by GCC configure.

Jason