libc++-based Debian

Description of the project: In the context of LLVM project, a new C++ standard library called libc++ has been developed and maintained. This package is already in Debian. The main goal is rebuild Debian using libc++ as C++ runtime. Note that the libstdc++ and libc++ are not ABI-compatible.

This project will take advantages of the debile infrastructure.

The first step of this project would be to propose a way to build every Debian C++ packages using libc++. The method must scale to the whole Debian archive (ie most of the packages should build out of the box using libc++).