A patch for time/time.h

[H.J. Lu]

> 
> hjl@lucon.org (H.J. Lu) writes:
> 
> > -D_POSIX_C_SOURCE=199506L
> > 
> > But it doesn't want to see those POSIX.2 stuff nor POSIX.4.
> 
> But then it is wrong.
> 
> The ISO 9945-1 standard (= POSIX.1 + .1b + .1c + .1i) defines that if
> _POSIX_C_SOURCE has a value greater or equal to 199506 then all
> mandatory definitions from this standard have to be added, and all
> extensions can be used.
> 

That is fine. But what is the reason behind

#if defined _POSIX_C_SOURCE && _POSIX_C_SOURCE >= 2 || defined _XOPEN_SOURCE
# define __USE_POSIX2   1
#endif

Why does _POSIX_C_SOURCE >= 2 mean POSIX.2?


H.J.