3.8.2/share/cmake-3.8/Modules/Compiler/AppleClang-CXX.cmake

include(Compiler/Clang)
__compiler_clang(CXX)

if(NOT "x${CMAKE_CXX_SIMULATE_ID}" STREQUAL "xMSVC")
  set(CMAKE_CXX_COMPILE_OPTIONS_VISIBILITY_INLINES_HIDDEN "-fvisibility-inlines-hidden")
endif()

if(NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 4.0)
  set(CMAKE_CXX98_STANDARD_COMPILE_OPTION "-std=c++98")
  set(CMAKE_CXX98_EXTENSION_COMPILE_OPTION "-std=gnu++98")

  set(CMAKE_CXX11_STANDARD_COMPILE_OPTION "-std=c++11")
  set(CMAKE_CXX11_EXTENSION_COMPILE_OPTION "-std=gnu++11")
endif()

if(NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 6.1)
  set(CMAKE_CXX14_STANDARD_COMPILE_OPTION "-std=c++14")
  set(CMAKE_CXX14_EXTENSION_COMPILE_OPTION "-std=gnu++14")
elseif(NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 5.1)
  # AppleClang 5.0 knows this flag, but does not set a __cplusplus macro greater than 201103L
  set(CMAKE_CXX14_STANDARD_COMPILE_OPTION "-std=c++1y")
  set(CMAKE_CXX14_EXTENSION_COMPILE_OPTION "-std=gnu++1y")
endif()

if (NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 6.1)
  set(CMAKE_CXX17_STANDARD_COMPILE_OPTION "-std=c++1z")
  set(CMAKE_CXX17_EXTENSION_COMPILE_OPTION "-std=gnu++1z")
endif()

if(NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 4.0)
  if (NOT CMAKE_CXX_COMPILER_FORCED)
    if (NOT CMAKE_CXX_STANDARD_COMPUTED_DEFAULT)
      message(FATAL_ERROR "CMAKE_CXX_STANDARD_COMPUTED_DEFAULT should be set for ${CMAKE_CXX_COMPILER_ID} (${CMAKE_CXX_COMPILER}) version ${CMAKE_CXX_COMPILER_VERSION}")
    endif()
    set(CMAKE_CXX_STANDARD_DEFAULT ${CMAKE_CXX_STANDARD_COMPUTED_DEFAULT})
  elseif(NOT DEFINED CMAKE_CXX_STANDARD_DEFAULT)
    # Compiler id was forced so just guess the default standard level.
    set(CMAKE_CXX_STANDARD_DEFAULT 98)
  endif()
endif()


macro(cmake_record_cxx_compile_features)
  set(_result 0)
  if (NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 4.0)
    if(_result EQUAL 0 AND CMAKE_CXX17_STANDARD_COMPILE_OPTION)
      _record_compiler_features_cxx(17)
    endif()
    if(_result EQUAL 0 AND CMAKE_CXX14_STANDARD_COMPILE_OPTION)
      _record_compiler_features_cxx(14)
    endif()
    if (_result EQUAL 0)
      _record_compiler_features_cxx(11)
    endif()
    if (_result EQUAL 0)
      _record_compiler_features_cxx(98)
    endif()
  endif()
endmacro()