Implement these traits using the new built-ins that Jakub added
recently.
Signed-off-by: Jonathan Wakely <jwakely@redhat.com>
libstdc++-v3/ChangeLog:
* include/std/type_traits (__cpp_lib_is_pointer_interconvertible)
(is_pointer_interconvertible_base_of_v)
(is_pointer_interconvertible_base_of): Define for C++20.
* include/std/version (__cpp_lib_is_pointer_interconvertible):
Define.
* testsuite/23_containers/span/layout_compat.cc: Use correct
feature test macro for std::is_layout_compatible_v.
* testsuite/20_util/is_pointer_interconvertible/value.cc: New test.
* testsuite/20_util/is_pointer_interconvertible/version.cc: New test.
4fa6c0ec35