[libcxx] Remove unexpected handlers in C++17 Summary: This patch implements [P0003R5](http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0003r5.html) which removes exception specifications from C++17. The only changes to the library are removing `set_unexpected`, `get_unexpected`, `unexpected`, and `unexpected_handler`. These functions can be re-enabled in C++17 using `_LIBCPP_ENABLE_CXX17_REMOVED_UNEXPECTED_FUNCTIONS`. @mclow.lists what do you think about removing stuff is this way? Reviewers: mclow.lists Reviewed By: mclow.lists Subscribers: mclow.lists, cfe-commits Differential Revision: https://reviews.llvm.org/D28172 git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@295406 91177308-0d34-0410-b5e6-96231b3b80d8 
diff --git a/include/exception b/include/exception index db11c36..8828709 100644 --- a/include/exception +++ b/include/exception 
@@ -112,10 +112,14 @@  };  #endif // !_LIBCPP_ABI_MICROSOFT   +#if _LIBCPP_STD_VER <= 14 \ + || defined(_LIBCPP_ENABLE_CXX17_REMOVED_UNEXPECTED_FUNCTIONS) \ + || defined(_LIBCPP_BUILDING_LIBRARY)  typedef void (*unexpected_handler)();  _LIBCPP_FUNC_VIS unexpected_handler set_unexpected(unexpected_handler) _NOEXCEPT;  _LIBCPP_FUNC_VIS unexpected_handler get_unexpected() _NOEXCEPT;  _LIBCPP_NORETURN _LIBCPP_FUNC_VIS void unexpected(); +#endif    typedef void (*terminate_handler)();  _LIBCPP_FUNC_VIS terminate_handler set_terminate(terminate_handler) _NOEXCEPT;