message: Remove error-prone CAF_INSTALL_CMAKEDIR option
  The custom CAF_INSTALL_CMAKEDIR option apparently introduced more
  potential pitfalls than it's worth. For full discussion/context see
  CMake package files now always land in
  `${CMAKE_INSTALL_LIBDIR}/cmake/CAF`.
diff: cmake_minimum_required(VERSION 3.5...3.18 FATAL_ERROR)
  project(CAF CXX)
  -cmake_policy(PUSH)
  -cmake_policy(VERSION 3.5...3.18)
  -
  # -- includes ------------------------------------------------------------------
  include(CMakeDependentOption)
  @@ -49,9 +46,6 @@ cmake_dependent_option(CAF_ENABLE_OPENSSL_MODULE "Build OpenSSL module" ON
  set(CAF_LOG_LEVEL "QUIET" CACHE STRING "Set log verbosity of CAF components")
  set(CAF_SANITIZERS "" CACHE STRING
  "Comma separated sanitizers, e.g., 'address,undefined'")
  -set(CAF_INSTALL_CMAKEDIR
  - "${CMAKE_INSTALL_FULL_LIBDIR}/cmake/CAF" CACHE PATH
  - "Path for installing CMake files, enables 'find_package(CAF)'")
  set(CAF_BUILD_INFO_FILE_PATH "" CACHE FILEPATH
  "Optional path for writing CMake and compiler version information")
  @@ -450,7 +444,7 @@ endif()
  export(EXPORT CAFTargets FILE CAFTargets.cmake NAMESPACE CAF::)
  install(EXPORT CAFTargets
  - DESTINATION "${CAF_INSTALL_CMAKEDIR}"
  + DESTINATION "${CMAKE_INSTALL_LIBDIR}/cmake/CAF"
  NAMESPACE CAF::)
  write_basic_package_version_file(
  @@ -461,15 +455,14 @@ write_basic_package_version_file(
  configure_package_config_file(
  "${CMAKE_CURRENT_SOURCE_DIR}/cmake/CAFConfig.cmake.in"
  "${CMAKE_CURRENT_BINARY_DIR}/CAFConfig.cmake"
  - INSTALL_DESTINATION "${CAF_INSTALL_CMAKEDIR}")
  + INSTALL_DESTINATION "${CMAKE_INSTALL_LIBDIR}/cmake/CAF")
  install(
  FILES
  "${CMAKE_CURRENT_BINARY_DIR}/CAFConfig.cmake"
  "${CMAKE_CURRENT_BINARY_DIR}/CAFConfigVersion.cmake"
  DESTINATION
  - "${CAF_INSTALL_CMAKEDIR}")
  -
  + "${CMAKE_INSTALL_LIBDIR}/cmake/CAF")
  # -- extra file output (primarily for CAF CI) ----------------------------------
  @@ -478,5 +471,3 @@ if(CAF_BUILD_INFO_FILE_PATH)
  "${CAF_BUILD_INFO_FILE_PATH}"
  @ONLY)
  endif()
  -
  -cmake_policy(POP)
  