(lib/error.h.in) New warnings when compiling "groff" [-Wredundant-decls]

[Bjarni Ingi Gislason]

Debian GNU/Linux 12 (bookworm)
Linux 6.1.27-1 x86_64 GNU/Linux
gcc (Debian 12.2.0-14) 12.2.0

[...]
  CC       lib/libgnu_a-openat-die.o
In file included from ../lib/openat-die.c:25:
./lib/error.h:28:3: warning: #include_next is a GCC extension
   28 | # include_next <error.h>
      |   ^~~~~~~~~~~~
In file included from ../lib/openat.h:28,
                 from ../lib/openat-die.c:20:
./lib/error.h:418:1: warning: redundant redeclaration of '_gl_cxxalias_dummy' 
[-Wredundant-decls]
  418 | _GL_CXXALIAS_SYS (error, void,
      | ^~~~~~~~~~~~~~~~
./lib/stdio.h:2266:1: note: previous declaration of '_gl_cxxalias_dummy' with 
type 'int'
 2266 | _GL_CXXALIASWARN (vsnprintf);
      | ^~~~~~~~~~~~~~~~
./lib/error.h:426:1: warning: redundant redeclaration of '_gl_cxxalias_dummy' 
[-Wredundant-decls]
  426 | _GL_CXXALIASWARN (error);
      | ^~~~~~~~~~~~~~~~
./lib/error.h:418:1: note: previous declaration of '_gl_cxxalias_dummy' with 
type 'int'
  418 | _GL_CXXALIAS_SYS (error, void,
      | ^~~~~~~~~~~~~~~~
./lib/error.h:455:1: warning: redundant redeclaration of '_gl_cxxalias_dummy' 
[-Wredundant-decls]
  455 | _GL_CXXALIAS_SYS (error_at_line, void,
      | ^~~~~~~~~~~~~~~~
./lib/error.h:426:1: note: previous declaration of '_gl_cxxalias_dummy' with 
type 'int'
  426 | _GL_CXXALIASWARN (error);
      | ^~~~~~~~~~~~~~~~
./lib/error.h:463:1: warning: redundant redeclaration of '_gl_cxxalias_dummy' 
[-Wredundant-decls]
  463 | _GL_CXXALIASWARN (error_at_line);
      | ^~~~~~~~~~~~~~~~
./lib/error.h:455:1: note: previous declaration of '_gl_cxxalias_dummy' with 
type 'int'
  455 | _GL_CXXALIAS_SYS (error_at_line, void,
      | ^~~~~~~~~~~~~~~~
./lib/error.h:468:15: warning: redundant redeclaration of 
'error_print_progname' [-Wredundant-decls]
  468 | extern void (*error_print_progname) (void);
      |               ^~~~~~~~~~~~~~~~~~~~
In file included from ./lib/error.h:28:
/usr/include/error.h:41:15: note: previous declaration of 
'error_print_progname' with type 'void (*)(void)'
   41 | extern void (*error_print_progname) (void);
      |               ^~~~~~~~~~~~~~~~~~~~
./lib/error.h:471:21: warning: redundant redeclaration of 'error_message_count' 
[-Wredundant-decls]
  471 | extern unsigned int error_message_count;
      |                     ^~~~~~~~~~~~~~~~~~~
/usr/include/error.h:44:21: note: previous declaration of 'error_message_count' 
with type 'unsigned int'
   44 | extern unsigned int error_message_count;
      |                     ^~~~~~~~~~~~~~~~~~~
./lib/error.h:475:12: warning: redundant redeclaration of 'error_one_per_line' 
[-Wredundant-decls]
  475 | extern int error_one_per_line;
      |            ^~~~~~~~~~~~~~~~~~
/usr/include/error.h:48:12: note: previous declaration of 'error_one_per_line' 
with type 'int'
   48 | extern int error_one_per_line;
      |            ^~~~~~~~~~~~~~~~~~
  CC       lib/libgnu_a-printf-frexp.o
[...]