libstdc++: Ensure all feature test macros have type long [PR87193]

libstdc++: Ensure all feature test macros have type long [PR87193]

This defines all the __cpp_lib_xxx macros as type long, as required by
the standard. We had an inconsistent mix of int and long, sometimes even
for the same macro name.

The __cpp_lib_experimental_xxx macros are left as type int, because
that's what it says in the relevant TS specs.

libstdc++-v3/ChangeLog:

	PR libstdc++/87193
	PR libstdc++/104019
	* include/bits/alloc_traits.h (__cpp_lib_allocator_traits_is_always_equal):
	Define as type long.
	* include/bits/allocator.h (__cpp_lib_incomplete_container_elements):
	Likewise.
	* include/bits/basic_string.h (__cpp_lib_string_udls): Likewise.
	* include/bits/chrono.h (__cpp_lib_chrono): Likewise.
	(__cpp_lib_chrono_udls): Likewise.
	* include/bits/move.h (__cpp_lib_addressof_constexpr): Likewise.
	* include/bits/node_handle.h (__cpp_lib_node_extract): Likewise.
	* include/bits/range_access.h (__cpp_lib_nonmember_container_access):
	Likewise.
	* include/bits/shared_ptr.h (__cpp_lib_enable_shared_from_this):
	Likewise.
	* include/bits/stl_algo.h (__cpp_lib_clamp): Likewise.
	(__cpp_lib_sample): Likewise.
	* include/bits/stl_algobase.h (__cpp_lib_robust_nonmodifying_seq_ops):
	Likewise.
	* include/bits/stl_function.h (__cpp_lib_transparent_operators):
	Likewise.
	* include/bits/stl_iterator.h (__cpp_lib_make_reverse_iterator):
	Likewise.
	* include/bits/stl_map.h (__cpp_lib_map_try_emplace):
	Likewise.
	* include/bits/stl_tree.h (__cpp_lib_generic_associative_lookup):
	Likewise.
	* include/bits/unique_ptr.h (__cpp_lib_make_unique):
	Likewise.
	* include/bits/unordered_map.h (__cpp_lib_unordered_map_try_emplace):
	Likewise.
	* include/c_global/cmath (__cpp_lib_hypot): Likewise.
	* include/c_global/cstddef (__cpp_lib_byte): Likewise.
	* include/std/atomic (__cpp_lib_atomic_is_always_lock_free):
	Likewise.
	* include/std/complex (__cpp_lib_complex_udls): Likewise.
	* include/std/filesystem (__cpp_lib_filesystem): Likewise.
	* include/std/functional (__cpp_lib_not_fn): Likewise.
	(__cpp_lib_boyer_moore_searcher): Likewise.
	* include/std/iomanip (__cpp_lib_quoted_string_io): Likewise.
	* include/std/mutex (__cpp_lib_scoped_lock): Likewise.
	* include/std/numeric (__cpp_lib_gcd_lcm): Likewise.
	(__cpp_lib_gcd, __cpp_lib_lcm): Likewise.
	* include/std/tuple (__cpp_lib_apply): Likewise.
	(__cpp_lib_make_from_tuple): Likewise.
	* include/std/type_traits (__cpp_lib_integral_constant_callable)
	(__cpp_lib_bool_constant, __cpp_lib_logical_traits)
	(__cpp_lib_is_null_pointer, __cpp_lib_transformation_trait_aliases)
	(__cpp_lib_result_of_sfinae, __cpp_lib_void_t)
	(__cpp_lib_is_swappable, __cpp_lib_is_invocable)
	(__cpp_lib_has_unique_object_representations)
	(__cpp_lib_is_aggregate): Likewise.
	* include/std/version: Likewise.
	* libsupc++/new (__cpp_lib_launder): Likewise.