module c-nullptr: error compiling groff

[Bjarni Ingi Gislason]

Debian testing (bookworm/sid)

gcc (Debian 12.2.0-14) 12.2.0

GNU Make 4.4.0.90


[...]
  CXX      src/roff/troff/env.o
In file included from /usr/include/c++/12/bits/stl_bvector.h:61,
                 from /usr/include/c++/12/vector:65,
                 from ../src/roff/troff/charinfo.h:20,
                 from ../src/roff/troff/env.cpp:31:
/usr/include/c++/12/bits/functional_hash.h:273:12: error: redefinition of 
'struct std::hash<long int>'
  273 |     struct hash<nullptr_t> : public __hash_base<size_t, nullptr_t>
      |            ^~~~~~~~~~~~~~~
/usr/include/c++/12/bits/functional_hash.h:157:3: note: previous definition of 
'struct std::hash<long int>'
  157 |   _Cxx_hashtable_define_trivial_hash(long)
      |   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
make[1]: *** [Makefile:10126: src/roff/troff/env.o] Error 1
make[1]: Leaving directory '/home/bg/git/groff/build'
make: *** [Makefile:6847: all] Error 2

modules in bootstrap.conf:

gnulib_modules="
    git-version-gen
    havelib
    manywarnings
    wcwidth
    fprintf-posix
    gen-header
    snprintf
    vsnprintf-posix
    warnings
  mkstemp
  fmod
  getcwd
  putenv
  strcase
  strerror
  strtol
  setlocale
  stdckdint
  assert
  assert-h
  idx
  string
  strings
  c-nullptr
 "
#  c-nullptr causes an error when compiling (5. Feb. 2023)