text: // Copyright (c) 1997-2013
  // Utrecht University (The Netherlands),
  // ETH Zurich (Switzerland),
  // INRIA Sophia-Antipolis (France),
  // Max-Planck-Institute Saarbruecken (Germany),
  // and Tel-Aviv University (Israel).  All rights reserved.
  //
  // This file is part of CGAL (www.cgal.org)
  //
  // $URL: https://github.com/CGAL/cgal/blob/releases/CGAL-5.0.2/Installation/include/CGAL/config.h $
  // $Id: config.h 52164b1 2019-10-19T15:34:59+02:00 Sébastien Loriot
  // SPDX-License-Identifier: LGPL-3.0-or-later OR LicenseRef-Commercial
  //
  //
  //
  // Author(s)     : Wieger Wesselink
  //                 Michael Hoffmann <hoffmann@inf.ethz.ch>
  //                 Sylvain Pion
  //                 Laurent Rineau
  
  #ifndef CGAL_CONFIG_H
  #define CGAL_CONFIG_H
  
  // CGAL is header-only by default since CGAL-5.0.
  #if !defined(CGAL_HEADER_ONLY) && ! CGAL_NOT_HEADER_ONLY
  #  define CGAL_HEADER_ONLY 1
  #endif
  
  #ifdef CGAL_HEADER_ONLY
  #  define CGAL_NO_AUTOLINK 1
  #endif
  
  // Workaround for a bug in Boost, that checks WIN64 instead of _WIN64
  //   https://svn.boost.org/trac/boost/ticket/5519
  #if defined(_WIN64) && ! defined(WIN64)
  #  define WIN64
  #endif
  
  #ifdef CGAL_INCLUDE_WINDOWS_DOT_H
  // Mimic users including this file which defines min max macros
  // and other names leading to name clashes
  #include <windows.h>
  #endif
  
  #if defined(CGAL_TEST_SUITE) && defined(NDEBUG)
  #  error The test-suite needs no NDEBUG defined
  #endif // CGAL_TEST_SUITE and NDEBUG
  
  // See [[Small features/Visual_Leak_Detector]] in CGAL developers wiki
  // See also: http://vld.codeplex.com/
  #if defined(CGAL_ENABLE_VLD)
  #  include <vld.h>
  #endif // CGAL_ENABLE_VLD
  
  // Workaround to the following bug:
  // https://bugreports.qt-project.org/browse/QTBUG-22829
  #ifdef Q_MOC_RUN
  // When Qt moc runs on CGAL files, do not process
  // <boost/type_traits/detail/has_binary_operator.hpp>
  #  define BOOST_TT_HAS_OPERATOR_HPP_INCLUDED
  #  define BOOST_TT_HAS_BIT_AND_HPP_INCLUDED
  #  define BOOST_TT_HAS_BIT_AND_ASSIGN_HPP_INCLUDED
  #  define BOOST_TT_HAS_BIT_OR_HPP_INCLUDED
  #  define BOOST_TT_HAS_BIT_OR_ASSIGN_HPP_INCLUDED
  #  define BOOST_TT_HAS_BIT_XOR_HPP_INCLUDED
  #  define BOOST_TT_HAS_BIT_XOR_ASSIGN_HPP_INCLUDED
  #  define BOOST_TT_HAS_DIVIDES_HPP_INCLUDED
  #  define BOOST_TT_HAS_DIVIDES_ASSIGN_HPP_INCLUDED
  #  define BOOST_TT_HAS_EQUAL_TO_HPP_INCLUDED
  #  define BOOST_TT_HAS_GREATER_HPP_INCLUDED
  #  define BOOST_TT_HAS_GREATER_EQUAL_HPP_INCLUDED
  #  define BOOST_TT_HAS_LEFT_SHIFT_HPP_INCLUDED
  #  define BOOST_TT_HAS_LEFT_SHIFT_ASSIGN_HPP_INCLUDED
  #  define BOOST_TT_HAS_LESS_HPP_INCLUDED
  #  define BOOST_TT_HAS_LESS_EQUAL_HPP_INCLUDED
  #  define BOOST_TT_HAS_LOGICAL_AND_HPP_INCLUDED
  #  define BOOST_TT_HAS_LOGICAL_OR_HPP_INCLUDED
  #  define BOOST_TT_HAS_MINUS_HPP_INCLUDED
  #  define BOOST_TT_HAS_MINUS_ASSIGN_HPP_INCLUDED
  #  define BOOST_TT_HAS_MODULUS_HPP_INCLUDED
  #  define BOOST_TT_HAS_MODULUS_ASSIGN_HPP_INCLUDED
  #  define BOOST_TT_HAS_MULTIPLIES_HPP_INCLUDED
  #  define BOOST_TT_HAS_MULTIPLIES_ASSIGN_HPP_INCLUDED
  #  define BOOST_TT_HAS_NOT_EQUAL_TO_HPP_INCLUDED
  #  define BOOST_TT_HAS_PLUS_HPP_INCLUDED
  #  define BOOST_TT_HAS_PLUS_ASSIGN_HPP_INCLUDED
  #  define BOOST_TT_HAS_RIGHT_SHIFT_HPP_INCLUDED
  #  define BOOST_TT_HAS_RIGHT_SHIFT_ASSIGN_HPP_INCLUDED
  // do not include <boost/random.hpp> either
  // it includes <boost/type_traits/has_binary_operator.hpp>
  #  define BOOST_RANDOM_HPP
  // <boost/type_traits/detail/has_prefix_operator.hpp> fails as well
  #  define BOOST_TT_HAS_COMPLEMENT_HPP_INCLUDED
  #  define BOOST_TT_HAS_DEREFERENCE_HPP_INCLUDED
  #  define BOOST_TT_HAS_LOGICAL_NOT_HPP_INCLUDED
  #  define BOOST_TT_HAS_NEGATE_HPP_INCLUDED
  #  define BOOST_TT_HAS_PRE_DECREMENT_HPP_INCLUDED
  #  define BOOST_TT_HAS_PRE_INCREMENT_HPP_INCLUDED
  #  define BOOST_TT_HAS_UNARY_MINUS_HPP_INCLUDED
  #  define BOOST_TT_HAS_UNARY_PLUS_HPP_INCLUDED
  // <boost/type_traits/detail/has_postfix_operator.hpp> fails as well
  #  define BOOST_TT_HAS_POST_DECREMENT_HPP_INCLUDED
  #  define BOOST_TT_HAS_POST_INCREMENT_HPP_INCLUDED
  #endif
  
  // Macro used by Boost Parameter. Mesh_3 needs at least 12, before the
  // Boost Parameter headers are included: <boost/parameter/config.hpp>
  // defines the value to 8, if it is not yet defined.
  // The CGAL BGL properties mechanism includes
  // <boost/graph/named_function_params.hpp>, that includes
  // <boost/parameter/name.hpp>, and maybe other Boost libraries may use
  // Boost Parameter as well.
  // That is why that is important to define that macro as early as possible,
  // in <CGAL/config.h>
  #define BOOST_PARAMETER_MAX_ARITY 12
  
  // The following header file defines among other things  BOOST_PREVENT_MACRO_SUBSTITUTION
  #include <boost/config.hpp>
  #include <boost/version.hpp>
  
  // bug-fix for g++-5.x and Boost.Config<1.57
  //    https://svn.boost.org/trac/boost/ticket/10500
  #if BOOST_VERSION < 105700 && BOOST_GCC < 60000 && \
    ! defined(__GXX_EXPERIMENTAL_CXX0X__) && defined(BOOST_HAS_VARIADIC_TMPL)
  #  undef BOOST_HAS_VARIADIC_TMPL
  #  define BOOST_NO_CXX11_VARIADIC_TEMPLATES
  #endif
  
  // workaround for the bug https://svn.boost.org/trac10/ticket/12534
  // That bug was introduced in Boost 1.62 and fixed in 1.63.
  #if BOOST_VERSION >= 106200 && BOOST_VERSION < 106300
  #  include <boost/container/flat_map.hpp>
  #endif
  
  // Hack: Boost<1.55 does not detect correctly the C++11 features of ICC.
  // We declare by hand two features that we need (variadic templates and
  // rvalue references).
  #if defined(__INTEL_COMPILER) && defined(__GXX_EXPERIMENTAL_CXX0X__)
  #  undef BOOST_NO_VARIADIC_TEMPLATES
  #  undef BOOST_NO_CXX11_VARIADIC_TEMPLATES
  #  undef BOOST_NO_RVALUE_REFERENCES
  #  undef BOOST_NO_CXX11_RVALUE_REFERENCES
  #endif
  
  #include <CGAL/version.h>
  
  //----------------------------------------------------------------------//
  //  platform specific workaround flags (CGAL_CFG_...)
  //----------------------------------------------------------------------//
  
  #if CGAL_HEADER_ONLY
  #  include <CGAL/internal/enable_third_party_libraries.h>
  #  if(BOOST_MSVC)
  #    include <CGAL/MSVC_compiler_config.h>
  #  endif
  #else
  #  include <CGAL/compiler_config.h>
  #endif
  
  #if BOOST_MSVC && CGAL_TEST_SUITE
  #  include <CGAL/Testsuite/vc_debug_hook.h>
  #endif
  
  //----------------------------------------------------------------------//
  //  Support for DLL on Windows (CGAL_EXPORT macro)
  //----------------------------------------------------------------------//
  
  #include <CGAL/export/CGAL.h>
  
  //----------------------------------------------------------------------//
  //  Use an implementation of fabs with sse2 on Windows
  //----------------------------------------------------------------------//
  
  #if (_M_IX86_FP >= 2) || defined(_M_X64)
  #define CGAL_USE_SSE2_FABS
  #endif
  
  //----------------------------------------------------------------------//
  //  Detect features at compile-time. Some macros have only been
  //  introduced as of Boost 1.40. In that case, we simply say that the
  //  feature is not available, even if that is wrong.
  //  ----------------------------------------------------------------------//
  
  #if defined(BOOST_NO_CXX11_RANGE_BASED_FOR) || BOOST_VERSION < 105000
  #define CGAL_CFG_NO_CPP0X_RANGE_BASED_FOR 1
  #endif
  #if defined(BOOST_NO_0X_HDR_ARRAY) || \
      defined(BOOST_NO_CXX11_HDR_ARRAY) || BOOST_VERSION < 104000
  #define CGAL_CFG_NO_CPP0X_ARRAY 1
  #endif
  #if defined(BOOST_NO_0X_HDR_UNORDERED_SET) || \
      defined(BOOST_NO_0X_HDR_UNORDERED_MAP) || \
      defined(BOOST_NO_CXX11_HDR_UNORDERED_SET) || \
      defined(BOOST_NO_CXX11_HDR_UNORDERED_MAP) || \
     (defined(_MSC_VER) && (_MSC_VER == 1800)) // std::unordered_set is very bad in MSVC2013
  #define CGAL_CFG_NO_CPP0X_UNORDERED 1
  #endif
  #if defined( BOOST_NO_0X_HDR_THREAD) || \
      defined( BOOST_NO_CXX11_HDR_THREAD)
  #define CGAL_CFG_NO_STD_THREAD 1
  #endif
  #if defined(BOOST_NO_DECLTYPE) || \
      defined(BOOST_NO_CXX11_DECLTYPE) || (BOOST_VERSION < 103600)
  #define CGAL_CFG_NO_CPP0X_DECLTYPE 1
  #endif
  #if defined(BOOST_NO_DELETED_FUNCTIONS) || \
      defined(BOOST_NO_DEFAULTED_FUNCTIONS) || \
      defined(BOOST_NO_CXX11_DELETED_FUNCTIONS) || \
      defined(BOOST_NO_CXX11_DEFAULTED_FUNCTIONS) || (BOOST_VERSION < 103600) || \
      (defined(_MSC_VER) && _MSC_VER < 1900) // MSVC 2013 has only partial support
  #define CGAL_CFG_NO_CPP0X_DELETED_AND_DEFAULT_FUNCTIONS 1
  #endif
  #if defined(BOOST_NO_FUNCTION_TEMPLATE_DEFAULT_ARGS) || \
      defined(BOOST_NO_CXX11_FUNCTION_TEMPLATE_DEFAULT_ARGS) || \
      (BOOST_VERSION < 104100)
  #define CGAL_CFG_NO_CPP0X_DEFAULT_TEMPLATE_ARGUMENTS_FOR_FUNCTION_TEMPLATES 1
  #endif
  #if defined(BOOST_NO_INITIALIZER_LISTS) || \
      defined(BOOST_NO_CXX11_HDR_INITIALIZER_LIST) || (BOOST_VERSION < 103900)
  #define CGAL_CFG_NO_CPP0X_INITIALIZER_LISTS 1
  #endif
  #if defined(BOOST_MSVC)
  #define CGAL_CFG_NO_CPP0X_ISFINITE 1 // used in <CGAL/CORE/Filter.h>
  #endif
  #if defined(BOOST_NO_LONG_LONG) || (BOOST_VERSION < 103600)
  #define CGAL_CFG_NO_CPP0X_LONG_LONG 1
  #endif
  #if defined(BOOST_NO_LAMBDAS) || \
      defined(BOOST_NO_CXX11_LAMBDAS) || BOOST_VERSION < 104000
  #define CGAL_CFG_NO_CPP0X_LAMBDAS 1
  #endif
  #if defined(BOOST_NO_RVALUE_REFERENCES) || \
      defined(BOOST_NO_CXX11_RVALUE_REFERENCES) || (BOOST_VERSION < 103600)
  #define CGAL_CFG_NO_CPP0X_RVALUE_REFERENCE 1
  #endif
  #if defined(BOOST_NO_STATIC_ASSERT) || \
      defined(BOOST_NO_CXX11_STATIC_ASSERT) || (BOOST_VERSION < 103600)
  #define CGAL_CFG_NO_CPP0X_STATIC_ASSERT 1
  #endif
  #if defined(BOOST_NO_0X_HDR_TUPLE) || \
      defined(BOOST_NO_CXX11_HDR_TUPLE) || (BOOST_VERSION < 104000)
  #define CGAL_CFG_NO_CPP0X_TUPLE 1
  #endif
  #if defined(BOOST_NO_VARIADIC_TEMPLATES) || \
      defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES) || (BOOST_VERSION < 103600)
  #define CGAL_CFG_NO_CPP0X_VARIADIC_TEMPLATES 1
  #endif
  // never use TR1
  #define CGAL_CFG_NO_TR1_ARRAY 1
  // never use TR1
  #define CGAL_CFG_NO_TR1_TUPLE 1
  #if !defined(__GNUC__) || defined(__INTEL_COMPILER)
  #define CGAL_CFG_NO_STATEMENT_EXPRESSIONS 1
  #endif
  #if defined(BOOST_NO_CXX11_UNIFIED_INITIALIZATION_SYNTAX) || (BOOST_VERSION < 105100) || _MSC_VER==1800
  #define CGAL_CFG_NO_CPP0X_UNIFIED_INITIALIZATION_SYNTAX
  #endif
  #if __cplusplus < 201103L && !(_MSC_VER >= 1600)
  #define CGAL_CFG_NO_CPP0X_COPY_N 1
  #define CGAL_CFG_NO_CPP0X_NEXT_PREV 1
  #endif
  #if defined(BOOST_NO_EXPLICIT_CONVERSION_OPERATIONS) \
      || defined(BOOST_NO_EXPLICIT_CONVERSION_OPERATORS) \
      || defined(BOOST_NO_CXX11_EXPLICIT_CONVERSION_OPERATORS) \
      || (BOOST_VERSION < 103600)
  #define CGAL_CFG_NO_CPP0X_EXPLICIT_CONVERSION_OPERATORS 1
  #endif
  #if defined(BOOST_NO_CXX11_TEMPLATE_ALIASES) || \
      defined(BOOST_NO_TEMPLATE_ALIASES) || (BOOST_VERSION < 103900)
  #define CGAL_CFG_NO_CPP0X_TEMPLATE_ALIASES 1
  #endif
  
  // Some random list to let us write C++11 without thinking about
  // each feature we are using.
  #if ( __cplusplus >= 201103L || _MSVC_LANG >= 201103L ) &&      \
      !defined CGAL_CFG_NO_CPP0X_VARIADIC_TEMPLATES && \
      !defined CGAL_CFG_NO_CPP0X_RVALUE_REFERENCE && \
      !defined CGAL_CFG_NO_CPP0X_EXPLICIT_CONVERSION_OPERATORS && \
      !defined CGAL_CFG_NO_CPP0X_TUPLE && \
      !defined CGAL_CFG_NO_CPP0X_UNIFIED_INITIALIZATION_SYNTAX && \
      !defined CGAL_CFG_NO_CPP0X_STATIC_ASSERT && \
      !defined CGAL_CFG_NO_CPP0X_DECLTYPE && \
      !defined CGAL_CFG_NO_CPP0X_DELETED_AND_DEFAULT_FUNCTIONS && \
      !defined CGAL_CFG_NO_CPP0X_DEFAULT_TEMPLATE_ARGUMENTS_FOR_FUNCTION_TEMPLATES
  #define CGAL_CXX11 1
  #endif
  // Same for C++14.
  #if __cplusplus >= 201402L || _MSVC_LANG >= 201402L
  #  define CGAL_CXX14 1
  #endif
  
  #if defined(BOOST_NO_CXX11_HDR_FUNCTIONAL) || BOOST_VERSION < 105000
  #define CGAL_CFG_NO_STD_HASH 1
  #define CGAL_CFG_NO_STD_FUNCTION 1
  #endif
  
  
  //----------------------------------------------------------------------//
  //  As std::unary_function and std::binary_function are deprecated
  //  we use internally equivalent class templates from
  // <CGAL/functional.h>.
  //----------------------------------------------------------------------//
  
  #include <CGAL/functional.h>
  
  //----------------------------------------------------------------------//
  //  auto-link the CGAL library on platforms that support it
  //----------------------------------------------------------------------//
  
  #include <CGAL/auto_link/CGAL.h>
  
  //----------------------------------------------------------------------//
  //  do some post processing for the flags
  //----------------------------------------------------------------------//
  
  #ifdef CGAL_CFG_NO_STL
  #  error "This compiler does not have a working STL"
  #endif
  
  // This macro computes the version number from an x.y.z release number.
  // It only works for public releases.
  #define CGAL_VERSION_NUMBER(x,y,z) (1000001 + 10000*x + 100*y + 10*z) * 1000
  
  #ifndef CGAL_NO_DEPRECATED_CODE
  #define CGAL_BEGIN_NAMESPACE  namespace CGAL {
  #define CGAL_END_NAMESPACE }
  #endif
  
  
  #ifndef CGAL_CFG_NO_CPP0X_LONG_LONG
  #  define CGAL_USE_LONG_LONG
  #endif
  
  
  #ifndef CGAL_CFG_TYPENAME_BEFORE_DEFAULT_ARGUMENT_BUG
  #  define CGAL_TYPENAME_DEFAULT_ARG typename
  #else
  #  define CGAL_TYPENAME_DEFAULT_ARG
  #endif
  
  
  #ifdef CGAL_CFG_NO_CPP0X_DELETED_AND_DEFAULT_FUNCTIONS
  #  define CGAL_DELETED
  #  define CGAL_EXPLICITLY_DEFAULTED
  #else
  #  define CGAL_DELETED = delete
  #  define CGAL_EXPLICITLY_DEFAULTED = default
  #endif
  
  
  // Big endian or little endian machine.
  // ====================================
  
  #if (BOOST_VERSION >= 105500)
  #  include <boost/predef.h>
  #  if BOOST_ENDIAN_BIG_BYTE
  #    define CGAL_BIG_ENDIAN
  #  elif BOOST_ENDIAN_LITTLE_BYTE
  #    define CGAL_LITTLE_ENDIAN
  #  endif
  #elif defined (__GLIBC__)
  #  include <endian.h>
  #  if (__BYTE_ORDER == __LITTLE_ENDIAN)
  #    define CGAL_LITTLE_ENDIAN
  #  elif (__BYTE_ORDER == __BIG_ENDIAN)
  #    define CGAL_BIG_ENDIAN
  #  endif
  #elif defined(__sparc) || defined(__sparc__) \
     || defined(_POWER) || defined(__powerpc__) \
     || defined(__ppc__) || defined(__hppa) \
     || defined(_MIPSEB) || defined(_POWER) \
     || defined(__s390__)
  #  define CGAL_BIG_ENDIAN
  #elif defined(__i386__) || defined(__alpha__) \
     || defined(__x86_64) || defined(__x86_64__) \
     || defined(__ia64) || defined(__ia64__) \
     || defined(_M_IX86) || defined(_M_IA64) \
     || defined(_M_ALPHA) || defined(_WIN64)
  #  define CGAL_LITTLE_ENDIAN
  #endif
  
  #if ! defined(CGAL_LITTLE_ENDIAN) && ! defined(CGAL_BIG_ENDIAN)
  #  ifdef CGAL_DEFAULT_IS_LITTLE_ENDIAN
  #    if CGAL_DEFAULT_IS_LITTLE_ENDIAN
  #      define CGAL_LITTLE_ENDIAN
  #    else
  #      define CGAL_BIG_ENDIAN
  #    endif
  #  else
  #    error Unknown endianness: Define CGAL_DEFAULT_IS_LITTLE_ENDIAN to 1 for little endian and to 0 for big endian.
  #  endif
  #endif
  // Symbolic constants to tailor inlining. Inlining Policy.
  // =======================================================
  #ifndef CGAL_MEDIUM_INLINE
  #  define CGAL_MEDIUM_INLINE inline
  #endif
  
  #ifndef CGAL_LARGE_INLINE
  #  define CGAL_LARGE_INLINE
  #endif
  
  #ifndef CGAL_HUGE_INLINE
  #  define CGAL_HUGE_INLINE
  #endif
  
  
  //----------------------------------------------------------------------//
  // SunPRO specific.
  //----------------------------------------------------------------------//
  #ifdef __SUNPRO_CC
  #  include <iterator>
  #  ifdef _RWSTD_NO_CLASS_PARTIAL_SPEC
  #    error "CGAL does not support SunPRO with the old Rogue Wave STL: use STLPort."
  #  endif
  #endif
  
  #ifdef __SUNPRO_CC
  // SunPRO 5.9 emits warnings "The variable tag has not yet been assigned a value"
  // even for empty "tag" variables.  No way to write a config/testfile for this.
  #  define CGAL_SUNPRO_INITIALIZE(C) C
  #else
  #  define CGAL_SUNPRO_INITIALIZE(C)
  #endif
  
  //----------------------------------------------------------------------//
  // MacOSX specific.
  //----------------------------------------------------------------------//
  
  #ifdef __APPLE__
  #  if defined(__GNUG__) && (__GNUG__ == 4) && (__GNUC_MINOR__ == 0) \
     && defined(__OPTIMIZE__) && !defined(CGAL_NO_WARNING_FOR_MACOSX_GCC_4_0_BUG)
  #    warning "Your configuration may exhibit run-time errors in CGAL code"
  #    warning "This appears with g++ 4.0 on MacOSX when optimizing"
  #    warning "You can disable this warning using -DCGAL_NO_WARNING_FOR_MACOSX_GCC_4_0_BUG"
  #    warning "For more information, see https://www.cgal.org/FAQ.html#mac_optimization_bug"
  #  endif
  #endif
  
  //-------------------------------------------------------------------//
  // When the global min and max are no longer defined (as macros)
  // because of NOMINMAX flag definition, we define our own global
  // min/max functions to make the Microsoft headers compile. (afxtempl.h)
  // Users that does not want the global min/max
  // should define CGAL_NOMINMAX
  //-------------------------------------------------------------------//
  #include <algorithm>
  #if defined NOMINMAX && !defined CGAL_NOMINMAX
  using std::min;
  using std::max;
  #endif
  
  //-------------------------------------------------------------------//
  // Is Geomview usable ?
  #if !defined(_MSC_VER) && !defined(__MINGW32__)
  #  define CGAL_USE_GEOMVIEW
  #endif
  
  
  //-------------------------------------------------------------------//
  // Compilers provide different macros to access the current function name
  #ifdef _MSC_VER
  #  define CGAL_PRETTY_FUNCTION __FUNCSIG__
  #elif defined __GNUG__
  #  define CGAL_PRETTY_FUNCTION __PRETTY_FUNCTION__
  #else
  #  define CGAL_PRETTY_FUNCTION __func__
  // with sunpro, this requires -features=extensions
  #endif
  
  // Macro to detect GCC versions.
  // It evaluates to 0 if the compiler is not GCC. Be careful that the Intel
  // compilers on Linux, and the LLVM/clang compiler both define GCC version
  // macros.
  #define CGAL_GCC_VERSION (__GNUC__ * 10000       \
                            + __GNUC_MINOR__ * 100 \
                            + __GNUC_PATCHLEVEL__)
  
  // Macros to detect features of clang. We define them for the other
  // compilers.
  // See http://clang.llvm.org/docs/LanguageExtensions.html
  // See also http://en.cppreference.com/w/cpp/experimental/feature_test
  #ifndef __has_feature
    #define __has_feature(x) 0  // Compatibility with non-clang compilers.
  #endif
  #ifndef __has_include
    #define __has_include(x) 0  // Compatibility with non-clang compilers.
  #endif
  #ifndef __has_extension
    #define __has_extension __has_feature // Compatibility with pre-3.0 compilers.
  #endif
  #ifndef __has_builtin
    #define __has_builtin(x) 0  // Compatibility with non-clang compilers.
  #endif
  #ifndef __has_attribute
    #define __has_attribute(x) 0  // Compatibility with non-clang compilers.
  #endif
  #ifndef __has_cpp_attribute
    #define __has_cpp_attribute(x) 0  // Compatibility with non-supporting compilers.
  #endif
  #ifndef __has_warning
    #define __has_warning(x) 0  // Compatibility with non-clang compilers.
  #endif
  
  // Macro to specify a 'unused' attribute.
  #if defined(__GNUG__) || __has_attribute(__unused__)
  #  define CGAL_UNUSED  __attribute__ ((__unused__))
  #else
  #  define CGAL_UNUSED
  #endif
  
  // Macro to trigger deprecation warnings
  #ifdef CGAL_NO_DEPRECATION_WARNINGS
  #  define CGAL_DEPRECATED
  #  define CGAL_DEPRECATED_UNUSED CGAL_UNUSED
  #elif defined(__GNUC__) || __has_attribute(__deprecated__)
  #  define CGAL_DEPRECATED __attribute__((__deprecated__))
  #if __has_attribute(__unused__)
  #  define CGAL_DEPRECATED_UNUSED __attribute__((__deprecated__, __unused__))
  #else
  #  define CGAL_DEPRECATED_UNUSED __attribute__((__deprecated__))
  #endif
  #elif defined (_MSC_VER) && (_MSC_VER > 1300)
  #  define CGAL_DEPRECATED __declspec(deprecated)
  #  define CGAL_DEPRECATED_UNUSED __declspec(deprecated)
  #else
  #  define CGAL_DEPRECATED
  #  define CGAL_DEPRECATED_UNUSED
  #endif
  
  // Macro to trigger deprecation warnings with a custom message
  #ifdef CGAL_NO_DEPRECATION_WARNINGS
  #  define CGAL_DEPRECATED_MSG(msg)
  #elif defined(__GNUC__) || __has_attribute(__deprecated__)
  #  if BOOST_GCC >= 40500 || __has_attribute(__deprecated__)
  #    define CGAL_DEPRECATED_MSG(msg) __attribute__ ((deprecated(msg)))
  #  else
  #    define CGAL_DEPRECATED_MSG(msg) __attribute__ ((deprecated))
  #  endif
  #elif defined (_MSC_VER) && (_MSC_VER > 1300)
  #  define CGAL_DEPRECATED_MSG(msg) __declspec(deprecated(msg))
  #elif defined(__clang__)
  #  define CGAL_DEPRECATED_MSG(msg) __attribute__ ((deprecated(msg)))
  #else
  #  define CGAL_DEPRECATED_MSG(msg)
  #endif
  
  // Macro to specify a 'noreturn' attribute.
  #if defined(__GNUG__) || __has_attribute(__noreturn__)
  #  define CGAL_NORETURN  __attribute__ ((__noreturn__))
  #elif defined (_MSC_VER)
  #  define CGAL_NORETURN __declspec(noreturn)
  #else
  #  define CGAL_NORETURN
  #endif
  
  // Macro to specify [[no_unique_address]] if supported
  #if __has_cpp_attribute(no_unique_address)
  #  define CGAL_NO_UNIQUE_ADDRESS [[no_unique_address]]
  #else
  #  define CGAL_NO_UNIQUE_ADDRESS
  #endif
  
  // Macro CGAL_ASSUME
  // Call a builtin of the compiler to pass a hint to the compiler
  #if __has_builtin(__builtin_unreachable) || (CGAL_GCC_VERSION >= 40500 && !__STRICT_ANSI__)
  // From g++ 4.5, there exists a __builtin_unreachable()
  // Also in LLVM/clang
  #  define CGAL_ASSUME(EX) if(!(EX)) { __builtin_unreachable(); }
  #elif defined(_MSC_VER)
  // MSVC has __assume
  #  define CGAL_ASSUME(EX) __assume(EX)
  #endif
  // If CGAL_ASSUME is not defined, then CGAL_assume and CGAL_assume_code are
  // defined differently, in <CGAL/assertions.h>
  
  // If CGAL_HAS_THREADS is not defined, then CGAL code assumes
  // it can do any thread-unsafe things (like using static variables).
  #if !defined CGAL_HAS_THREADS && !defined CGAL_HAS_NO_THREADS
  #  if defined BOOST_HAS_THREADS || defined _OPENMP
  #    define CGAL_HAS_THREADS
  #  endif
  #endif
  
  #if __has_feature(cxx_thread_local) || \
      ( (__GNUC__ * 100 + __GNUC_MINOR__) >= 408 && __cplusplus >= 201103L ) || \
      ( _MSC_VER >= 1900 )
  // see also Installation/cmake/modules/config/support/CGAL_test_cpp_version.cpp
  #define CGAL_CAN_USE_CXX11_THREAD_LOCAL
  #endif
  
  #if ( BOOST_VERSION >= 105000 && ! defined(BOOST_NO_CXX11_HDR_MUTEX) ) || \
      (__has_include(<mutex>) && __cplusplus >= 201103L ) | \
      ( (__GNUC__ * 100 + __GNUC_MINOR__) >= 408 && __cplusplus >= 201103L ) || \
      ( _MSC_VER >= 1700 )
  #define CGAL_CAN_USE_CXX11_MUTEX
  #endif
  
  #if ( BOOST_VERSION >= 105600 && ! defined(BOOST_NO_CXX11_HDR_ATOMIC) ) || \
      (__has_include(<atomic>) && __cplusplus >= 201103L ) || \
      ( (__GNUC__ * 100 + __GNUC_MINOR__) >= 408 && __cplusplus >= 201103L ) || \
      ( _MSC_VER >= 1700 )
  #define CGAL_CAN_USE_CXX11_ATOMIC
  #endif
  
  // Support for LEDA with threads
  //   Not that, if CGAL_HAS_THREADS is defined, and you want to use LEDA,
  //   you must link with a version of LEDA libraries that support threads.
  #if defined(CGAL_HAS_THREADS) && CGAL_USE_LEDA
  #  define LEDA_MULTI_THREAD 1
  #endif
  // Support for LEDA_numbers on Windows
  #define LEDA_NUMBERS_DLL 1
  
  // Helper macros to disable macros
  #if defined(__clang__) || (BOOST_GCC >= 40600)
  #  define CGAL_PRAGMA_DIAG_PUSH _Pragma("GCC diagnostic push")
  #  define CGAL_PRAGMA_DIAG_POP  _Pragma("GCC diagnostic pop")
  #else
  #  define CGAL_PRAGMA_DIAG_PUSH
  #  define CGAL_PRAGMA_DIAG_POP
  #endif
  
  //
  // Compatibility with CGAL-4.14.
  //
  // That is temporary, and will be replaced by a namespace alias, as
  // soon as we can remove cpp11::result_of, and <CGAL/atomic.h> and
  // <CGAL/thread.h>.
  //
  #  include <iterator>
  #  include <array>
  #  include <utility>
  #  include <type_traits>
  #  include <unordered_set>
  #  include <unordered_map>
  #  include <functional>
  //
  namespace CGAL {
  //
    namespace cpp11 {
      using std::next;
      using std::prev;
      using std::copy_n;
      using std::array;
      using std::function;
      using std::tuple;
      using std::make_tuple;
      using std::tie;
      using std::get;
      using std::tuple_size;
      using std::tuple_element;
      using std::is_enum;
      using std::unordered_set;
      using std::unordered_map;
    }
  //
    namespace cpp0x = cpp11;
    using cpp11::array;
    using cpp11::copy_n;
  } // end of the temporary compatibility with CGAL-4.14
  
  namespace CGAL {
  
  // Typedef for the type of nullptr.
  typedef const void * Nullptr_t;   // Anticipate C++0x's std::nullptr_t
  
  } //namespace CGAL
  
  //Support for c++11 noexcept
  #if BOOST_VERSION > 104600 && !defined(BOOST_NO_CXX11_NOEXCEPT) && !defined(BOOST_NO_NOEXCEPT)
  #define CGAL_NOEXCEPT(x) noexcept(x)
  #else
  #define CGAL_NOEXCEPT(x)
  #endif
  
  // The fallthrough attribute
  // See for clang:
  //   http://clang.llvm.org/docs/AttributeReference.html#statement-attributes
  // See for gcc:
  //   https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html
  #if __cpp_attributes >= 200809 && __has_cpp_attribute(fallthrough)
  #  define CGAL_FALLTHROUGH [[fallthrough]]
  #elif __cpp_attributes >= 200809 && __has_cpp_attribute(gnu::fallthrough)
  #  define CGAL_FALLTHROUGH [[gnu::fallthrough]]
  #elif __cpp_attributes >= 200809 && __has_cpp_attribute(clang::fallthrough)
  #  define CGAL_FALLTHROUGH [[clang::fallthrough]]
  #elif __has_attribute(fallthrough) && ! __clang__
  #  define CGAL_FALLTHROUGH __attribute__ ((fallthrough))
  #else
  #  define CGAL_FALLTHROUGH while(false){}
  #endif
  
  // https://svn.boost.org/trac/boost/ticket/2839
  #if defined(BOOST_MSVC) && BOOST_VERSION < 105600
  #define CGAL_CFG_BOOST_VARIANT_SWAP_BUG 1
  #endif
  
  #ifndef CGAL_NO_ASSERTIONS
  #  define CGAL_NO_ASSERTIONS_BOOL false
  #else
  #  define CGAL_NO_ASSERTIONS_BOOL true
  #endif
  
  #if defined( __INTEL_COMPILER)
  #define CGAL_ADDITIONAL_VARIANT_FOR_ICL ,int
  #else
  #define CGAL_ADDITIONAL_VARIANT_FOR_ICL
  #endif
  
  #if !defined CGAL_EIGEN3_ENABLED && \
      !defined CGAL_EIGEN3_DISABLED && \
      __has_include(<Eigen/Jacobi>)
  #  define CGAL_EIGEN3_ENABLED 1
  #endif
  
  #define CGAL_STRINGIZE_HELPER(x) #x
  #define CGAL_STRINGIZE(x) CGAL_STRINGIZE_HELPER(x)
  
  /// Macro `CGAL_WARNING`.
  /// Must be used with `#pragma`, this way:
  ///
  ///     #pragma CGAL_WARNING(This line should trigger a warning)
  ///
  /// @{
  #ifdef BOOST_MSVC
  #  define CGAL_WARNING(desc) message(__FILE__ "(" CGAL_STRINGIZE(__LINE__) ") : warning: " desc)
  #else // not BOOST_MSVC
  #  define CGAL_WARNING(desc) message( "warning: " desc)
  #endif // not BOOST_MSVC
  /// @}
  
  /// Macro `CGAL_pragma_warning`.
  /// @{
  #ifdef BOOST_MSVC
  #  define CGAL_pragma_warning(desc) __pragma(CGAL_WARNING(desc))
  #else // not BOOST_MSVC
  #  define CGAL_pragma_warning(desc) _Pragma(CGAL_STRINGIZE(CGAL_WARNING(desc)))
  #endif // not BOOST_MSVC
  /// @}
  #include <CGAL/license/lgpl.h>
  
  
  #endif // CGAL_CONFIG_H
  