add a formula for compiling cryptopp with libstdc++

As described here http://blog.inventic.eu/2014/01/qt-on-osx-maverick-undefined-symbols-for-architecture-x86_64/ you need to compile cryptopp with libstdc++ to include it into a qt project
this formula is a copy of the cryptopp formula, so I'm not quite sure what you mean by that?