text: #ifndef RBIMPL_COMPILER_IS_APPLE_H                   /*-*-C++-*-vi:se ft=cpp:*/
  #define RBIMPL_COMPILER_IS_APPLE_H
  /**
   * @author     Ruby developers <ruby-core@ruby-lang.org>
   * @copyright  This  file  is   a  part  of  the   programming  language  Ruby.
   *             Permission  is hereby  granted,  to  either redistribute  and/or
   *             modify this file, provided that  the conditions mentioned in the
   *             file COPYING are met.  Consult the file for details.
   * @warning    Symbols   prefixed  with   either  `RBIMPL`   or  `rbimpl`   are
   *             implementation details.   Don't take  them as canon.  They could
   *             rapidly appear then vanish.  The name (path) of this header file
   *             is also an  implementation detail.  Do not expect  it to persist
   *             at the place it is now.  Developers are free to move it anywhere
   *             anytime at will.
   * @note       To  ruby-core:  remember  that   this  header  can  be  possibly
   *             recursively included  from extension  libraries written  in C++.
   *             Do not  expect for  instance `__VA_ARGS__` is  always available.
   *             We assume C99  for ruby itself but we don't  assume languages of
   *             extension libraries.  They could be written in C++98.
   * @brief      Defines RBIMPL_COMPILER_IS_Apple.
   *
   * Apple  ships clang.   Problem is,  its  `__clang_major__` etc.  are not  the
   * upstream LLVM  version, but XCode's.  We  have to think Apple's  is distinct
   * from LLVM's,  when it comes  to compiler  detection business in  this header
   * file.
   */
  #if ! defined(__clang__)
  # define RBIMPL_COMPILER_IS_Apple 0
  
  #elif ! defined(__apple_build_version__)
  # define RBIMPL_COMPILER_IS_Apple 0
  
  #else
  # define RBIMPL_COMPILER_IS_Apple 1
  # define RBIMPL_COMPILER_VERSION_MAJOR __clang_major__
  # define RBIMPL_COMPILER_VERSION_MINOR __clang_minor__
  # define RBIMPL_COMPILER_VERSION_PATCH __clang_patchlevel__
  #endif
  
  #endif /* RBIMPL_COMPILER_IS_APPLE_H */
  