MinGW do not support std::defaultfloat, how to lead with it?

Every compiler has its own set of implemented and not implemented features of the standard, that is sad but it is life.

While trying to compile our project done for VS to MinGW, I got an error with

std::defaultfloat

ERROR: "defaultfloat" is not member of "std"

It seem that his feature of C++11 is still not implemented.

I would like to make some conditional code to avoid this error, but without removing the feature:

#ifdef std::defaultfloat
    stream << std::defaultfloat << value;
#else
    // My own temporal equivalent
#endif

That of course do not work, cause of namespace, and I wonder if there is a better alternative to precompiler instructions.