[PATCH. libstdc++] Use the correct C++14 __cplusplus value (201402L). Added C++1z to the preprocessor.

[Paolo Carlini]

Hi,

On 08/26/2014 10:56 AM, Rainer Orth wrote:
> bits/c++config...
> Which won't help users seeing them in the headers.  Maybe the issue
> could be avoided by chosing names that make it clear that they are
> g++/libstdc++ specific, not generic?
Sure, whatever works, the names were tentative, for the cpp idea.

Paolo.