message: Fix the missing install name dir on osx
  This commit allows installed adios2 executables to find its
  dependencies properly on osx.
diff: @@ -25,6 +25,11 @@ set(CMAKE_INSTALL_CMAKEDIR ${CMAKE_INSTALL_LIBDIR}/cmake/adios2
  CACHE STRING "Installation CMake subdirectory")
  mark_as_advanced(CMAKE_INSTALL_CMAKEDIR)
  +# On Mac OS X, set the dir. included as part of the installed library's path:
  +if (BUILD_SHARED_LIBS AND NOT DEFINED CMAKE_INSTALL_NAME_DIR)
  + set(CMAKE_INSTALL_NAME_DIR "${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_LIBDIR}")
  +endif ()
  +
  list(INSERT CMAKE_MODULE_PATH 0 "${PROJECT_SOURCE_DIR}/cmake")
  if(NOT CMAKE_ARCHIVE_OUTPUT_DIRECTORY)
  set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY
  