Your browser does not seem to support JavaScript. As a result, your viewing experience will be diminished, and you have been placed in read-only mode.
Please download a browser that supports JavaScript, or enable it if it's disabled (i.e. NoScript).
Yes it is but the g++ mkspec is tailored for when there was only g++ hence it's linking to libstdc++ and not libc++.
That mkspec is to be considered deprecated and not used anymore.