Link different C++ standard libraries on Mac OS X

Question

Now that multiple C++ standard libraries can exist on Mac OS X, it now looks like quite a chaotic situation. According to https://stackoverflow.com/a/8457799/1772681, mixing

Answer 1

I don't speak for Apple, but watching their actions, I believe that their goal is to get back to one standard library implementation for Mac OS (and iOS) - and that will be libc++. I believe that sometime in the future, libstdc++ will no longer be part of Mac OS X.

Can we mix system libc++ and manually built Clang libc++? If not, when will it cause trouble?

I do this fairly regularly - but I don't replace the one in usr/lib. Instead I run specific programs after setting the environment variable DYLD_LIBRARY_PATH to point to my newly built libc++. Replacing the one in /usr/lib has the potential to brick your system. (if you break something in the dylib - or even just change the layout of std::string, say).