c++ error when trying to build releng/14.2 on 'main' host

From: Andriy Gapon <avg_at_FreeBSD.org>
Date: Tue, 08 Apr 2025 19:39:32 UTC 
The build machine is amd64 15.0-CURRENT built from commit d6ed5ff4ac7d96 from 
2024/12/03.  A bit dated, I know, but not really old.

The error is:

In file included from 
/usr/obj/usr/src/releng142/amd64.amd64/tmp/usr/include/c++/v1/memory:944:
/usr/obj/usr/src/releng142/amd64.amd64/tmp/usr/include/c++/v1/__memory/uses_allocator_construction.h:204:5: 
error: '__exclude_from_explicit_instantiation__' attribute ignored on local 
class member [-Werror,-Wignored-attributes]
   204 |     _LIBCPP_HIDE_FROM_ABI constexpr operator _PairMutable() const {
       |     ^
/usr/obj/usr/src/releng142/amd64.amd64/tmp/usr/include/c++/v1/__config:859:22: 
note: expanded from macro '_LIBCPP_HIDE_FROM_ABI'
   859 |       _LIBCPP_HIDDEN _LIBCPP_EXCLUDE_FROM_EXPLICIT_INSTANTIATION 
                                                \
       |                      ^
/usr/obj/usr/src/releng142/amd64.amd64/tmp/usr/include/c++/v1/__config:785:72: 
note: expanded from macro '_LIBCPP_EXCLUDE_FROM_EXPLICIT_INSTANTIATION'
   785 | #    define _LIBCPP_EXCLUDE_FROM_EXPLICIT_INSTANTIATION 
__attribute__((__exclude_from_explicit_instantiation__))

Not sure what I did to deserve this :-)

-- 
Andriy Gapon