When libc++ is built with experimental features enabled, we link the
c++experimental.a static library directly into libc++.dylib, which
allows users to avoid using -lc++experimental in order to use
It makes sense to me that when libc++ is configured with experimental
features enabled, it should just work. Of course, vendors are free to
follow a different course of action, since they may not want to ship
experimental features in their dylib (in which case they can simply
turn off the experimental library in their build).