[libcpp] Correctly define __cplusplus (PR libstdc++-v3/1773)

[Gabriel Dos Reis]

On Wed, Aug 10, 2011 at 7:12 AM, Rainer Orth
<ro@cebitec.uni-bielefeld.de> wrote:
> Jason Merrill <jason@redhat.com> writes:
>
>> On 08/09/2011 09:14 AM, Marc Glisse wrote:
>>> I don't think we should define the C++ 2011 value yet. In my opinion, we
>>> should wait until:
>>> 1) the standard is official
>>> 2) gcc implements most of it: people will want to use __cplusplus as a
>>> test to know if they can use C++0X features, not if the compiler does
>>> some effort to implement half of them.
>>
>> I'm of two minds about this, but I see that clang and edg still use 199711L
>> in C++0x mode, so let's stick with that for now.
>
> Ok, I just wanted to bring it up.  I'll resubmit with the 201103L change
> removed once the other patches (tm etc. mangling and libstdc++) are
> resolved.

After the experience with C++98 implementation, I have also become two-minded
about this.  In the end I agree with Jason that we should just keep
the C++03 value
for the moment.