message: COMP: Allow install lib directory name changes
  Follows InsightSoftwareConsortium/ITK@5b09d546666f6110250aa7edbb59d4469791b944
diff: @@ -39,20 +39,23 @@ set(RTK_LIBRARIES RTK)
  #=========================================================
  # Installation variables
  #=========================================================
  +if(NOT CMAKE_INSTALL_LIBDIR)
  + set(CMAKE_INSTALL_LIBDIR lib)
  +endif()
  if(NOT RTK_INSTALL_RUNTIME_DIR)
  set(RTK_INSTALL_RUNTIME_DIR bin)
  endif()
  if(NOT RTK_INSTALL_LIB_DIR)
  - set(RTK_INSTALL_LIB_DIR lib)
  + set(RTK_INSTALL_LIB_DIR ${CMAKE_INSTALL_LIBDIR})
  endif()
  if(NOT RTK_INSTALL_ARCHIVE_DIR)
  - set(RTK_INSTALL_ARCHIVE_DIR lib)
  + set(RTK_INSTALL_ARCHIVE_DIR ${CMAKE_INSTALL_LIBDIR})
  endif()
  if(NOT RTK_INSTALL_INCLUDE_DIR)
  set(RTK_INSTALL_INCLUDE_DIR include/RTK)
  endif()
  if(NOT RTK_INSTALL_PACKAGE_DIR)
  - set(RTK_INSTALL_PACKAGE_DIR "lib/cmake/RTK")
  + set(RTK_INSTALL_PACKAGE_DIR "${CMAKE_INSTALL_LIBDIR}/cmake/RTK")
  endif()
  #Set position independent code for Unix (-fPIC)
  @@ -131,10 +134,10 @@ if(NOT CMAKE_RUNTIME_OUTPUT_DIRECTORY)
  set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${RTK_BINARY_DIR}/bin)
  endif()
  if(NOT CMAKE_LIBRARY_OUTPUT_DIRECTORY)
  - set(CMAKE_LIBRARY_OUTPUT_DIRECTORY ${RTK_BINARY_DIR}/lib)
  + set(CMAKE_LIBRARY_OUTPUT_DIRECTORY ${RTK_BINARY_DIR}/${CMAKE_INSTALL_LIBDIR})
  endif()
  if(NOT CMAKE_ARCHIVE_OUTPUT_DIRECTORY)
  - set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${RTK_BINARY_DIR}/lib)
  + set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${RTK_BINARY_DIR}/${CMAKE_INSTALL_LIBDIR})
  endif()
  #=========================================================
  