toolchain/54644: can not build new gcc on -current as of a few days ago

[martin%NetBSD.org@localhost]

>Number:         54644
>Category:       toolchain
>Synopsis:       can not build new gcc on -current as of a few days ago
>Confidential:   no
>Severity:       critical
>Priority:       high
>Responsible:    toolchain-manager
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Wed Oct 23 09:50:01 +0000 2019
>Originator:     Martin Husemann
>Release:        NetBSD 9.99.17
>Organization:
The NetBSD Foundation, Inc.
>Environment:
System: NetBSD seven-days-to-the-wolves.aprisoft.de 9.99.17 NetBSD 9.99.17 (GENERIC) #313: Sun Oct 13 10:57:23 CEST 2019 martin%seven-days-to-the-wolves.aprisoft.de@localhost:/work/src/sys/arch/amd64/compile/GENERIC amd64
Architecture: x86_64
Machine: amd64
>Description:

Trying to build -current amd64 on -current (as of a few days ago) fails for
me:

--- errors.lo ---
In file included from /usr/include/g++/bits/move.h:55:0,
                 from /usr/include/g++/bits/nested_exception.h:40,
                 from /usr/include/g++/exception:144,
                 from /usr/include/g++/new:40,
                 from /work/src/external/gpl3/gcc/dist/gcc/system.h:242,
                 from /work/src/external/gpl3/gcc/dist/gcc/errors.c:30:
/usr/include/g++/type_traits:921:32: error: there are no arguments to '__is_constructible' that depend on a template parameter, so a declaration of '__is_constructible' must be available [-fpermissive]
       : public __bool_constant<__is_constructible(_Tp, _Args...)>
                                ^~~~~~~~~~~~~~~~~~
/usr/include/g++/type_traits:921:32: note: (if you use '-fpermissive', G++ will accept your code, but allowing the use of an undeclared name is deprecated)
/usr/include/g++/type_traits:921:65: error: template argument 1 is invalid
       : public __bool_constant<__is_constructible(_Tp, _Args...)>
                                                                 ^
/usr/include/g++/type_traits:1049:32: error: there are no arguments to '__is_assignable' that depend on a template parameter, so a declaration of '__is_assignable' must be available [-fpermissive]
       : public __bool_constant<__is_assignable(_Tp, _Up)>
                                ^~~~~~~~~~~~~~~
/usr/include/g++/type_traits:1049:57: error: template argument 1 is invalid
       : public __bool_constant<__is_assignable(_Tp, _Up)>
                                                         ^
In file included from /work/src/external/gpl3/gcc/dist/gcc/system.h:243:0,
                 from /work/src/external/gpl3/gcc/dist/gcc/errors.c:30:
/usr/include/g++/utility:307:35: error: there are no arguments to '__integer_pack' that depend on a template parameter, so a declaration of '__integer_pack' must be available [-fpermissive]
       using __type = _Index_tuple<__integer_pack(_Num)...>;
                                   ^~~~~~~~~~~~~~
/usr/include/g++/utility:307:55: error: expansion pattern '__integer_pack(_Num)' contains no argument packs
       using __type = _Index_tuple<__integer_pack(_Num)...>;
                                                       ^~~
/usr/include/g++/utility:307:58: error: template argument 1 is invalid
       using __type = _Index_tuple<__integer_pack(_Num)...>;
                                                          ^
/usr/include/g++/utility:329:51: error: expansion pattern '__integer_pack(_Num)' contains no argument packs
       = integer_sequence<_Tp, __integer_pack(_Num)...>;
                                                   ^~~
/usr/include/g++/utility:329:54: error: template argument 2 is invalid
       = integer_sequence<_Tp, __integer_pack(_Num)...>;
                                                      ^
/usr/include/g++/utility:340:33: error: 'make_integer_sequence' does not name a type; did you mean 'integer_sequence'?
     using make_index_sequence = make_integer_sequence<size_t, _Num>;
                                 ^~~~~~~~~~~~~~~~~~~~~
                                 integer_sequence
/usr/include/g++/utility:344:32: error: 'make_index_sequence' does not name a type; did you mean 'index_sequence'?
     using index_sequence_for = make_index_sequence<sizeof...(_Types)>;
                                ^~~~~~~~~~~~~~~~~~~
                                index_sequence
*** [errors.lo] Error code 1
nbmake[8]: stopped in /work/src/external/gpl3/gcc/usr.bin/common-target


>How-To-Repeat:
Try to build on -current

>Fix:
n/a