Binary package “libc++-7-dev” in ubuntu cosmic

LLVM C++ Standard library (development files)

 libc++ is another implementation of the C++ standard library
 Features and Goals
   * Correctness as defined by the C++ standards.
   * Fast execution.
   * Minimal memory use.
   * Fast compile times.
   * ABI compatibility with gcc's libstdc++ for some low-level features such
     as exception objects, rtti and memory allocation.
   * Extensive unit tests.