Update from Gnulib by running admin/merge-gnulib

* lib/dirent-private.h, m4/codeset.m4, m4/locale-fr.m4, m4/musl.m4:
New files, from Gnulib.

58 files changed, 758 insertions, 153 deletions

diff --git a/lib/acl-internal.h b/lib/acl-internal.h
index c97e847cdc5..496e41d7b21 100644
--- a/lib/acl-internal.h
+++ b/lib/acl-internal.h
@@ -17,6 +17,11 @@
 
    Written by Paul Eggert, Andreas Grünbacher, and Bruno Haible.  */
 
+/* This file uses _GL_INLINE_HEADER_BEGIN, _GL_INLINE, _GL_ATTRIBUTE_PURE.  */
+#if !_GL_CONFIG_H_INCLUDED
+ #error "Please include config.h first."
+#endif
+
 #include "acl.h"
 
 #include <stdlib.h>
@@ -60,9 +65,6 @@ extern int aclsort (int, int, struct acl *);
 # define fchmod(fd, mode) (-1)
 #endif
 
-#ifndef _GL_INLINE_HEADER_BEGIN
- #error "Please include config.h first."
-#endif
 _GL_INLINE_HEADER_BEGIN
 #ifndef ACL_INTERNAL_INLINE
 # define ACL_INTERNAL_INLINE _GL_INLINE
diff --git a/lib/acl.h b/lib/acl.h
index 58e5797179e..0d021200556 100644
--- a/lib/acl.h
+++ b/lib/acl.h
@@ -20,6 +20,11 @@
 #ifndef _GL_ACL_H
 #define _GL_ACL_H 1
 
+/* This file uses _GL_ATTRIBUTE_CONST.  */
+#if !_GL_CONFIG_H_INCLUDED
+ #error "Please include config.h first."
+#endif
+
 #include <sys/types.h>
 #include <sys/stat.h>
 
diff --git a/lib/attribute.h b/lib/attribute.h
index 130644d8798..9464fde0f30 100644
--- a/lib/attribute.h
+++ b/lib/attribute.h
@@ -41,6 +41,21 @@
      These names begin with 'ATTRIBUTE_' to avoid name clashes.  */
 
 
+/* This file uses _GL_ATTRIBUTE_ALLOC_SIZE, _GL_ATTRIBUTE_ALWAYS_INLINE,
+   _GL_ATTRIBUTE_ARTIFICIAL, _GL_ATTRIBUTE_COLD, _GL_ATTRIBUTE_CONST,
+   _GL_ATTRIBUTE_DEALLOC, _GL_ATTRIBUTE_DEPRECATED, _GL_ATTRIBUTE_ERROR,
+   _GL_ATTRIBUTE_WARNING, _GL_ATTRIBUTE_EXTERNALLY_VISIBLE,
+   _GL_ATTRIBUTE_FALLTHROUGH, _GL_ATTRIBUTE_FORMAT, _GL_ATTRIBUTE_LEAF,
+   _GL_ATTRIBUTE_MALLOC, _GL_ATTRIBUTE_MAY_ALIAS, _GL_ATTRIBUTE_MAYBE_UNUSED,
+   _GL_ATTRIBUTE_NODISCARD, _GL_ATTRIBUTE_NOINLINE, _GL_ATTRIBUTE_NONNULL,
+   _GL_ATTRIBUTE_NONSTRING, _GL_ATTRIBUTE_NOTHROW, _GL_ATTRIBUTE_PACKED,
+   _GL_ATTRIBUTE_PURE, _GL_ATTRIBUTE_RETURNS_NONNULL,
+   _GL_ATTRIBUTE_SENTINEL.  */
+#if !_GL_CONFIG_H_INCLUDED
+ #error "Please include config.h first."
+#endif
+
+
 /* =============== Attributes for specific kinds of functions =============== */
 
 /* Attributes for functions that should not be used.  */
diff --git a/lib/binary-io.h b/lib/binary-io.h
index 6f4db253354..855d6f819f0 100644
--- a/lib/binary-io.h
+++ b/lib/binary-io.h
@@ -17,6 +17,11 @@
 #ifndef _BINARY_H
 #define _BINARY_H
 
+/* This file uses _GL_INLINE_HEADER_BEGIN, _GL_INLINE, _GL_UNUSED.  */
+#if !_GL_CONFIG_H_INCLUDED
+ #error "Please include config.h first."
+#endif
+
 /* For systems that distinguish between text and binary I/O.
    O_BINARY is guaranteed by the gnulib <fcntl.h>. */
 #include <fcntl.h>
@@ -25,9 +30,6 @@
    so we include it here first.  */
 #include <stdio.h>
 
-#ifndef _GL_INLINE_HEADER_BEGIN
- #error "Please include config.h first."
-#endif
 _GL_INLINE_HEADER_BEGIN
 #ifndef BINARY_IO_INLINE
 # define BINARY_IO_INLINE _GL_INLINE
diff --git a/lib/c++defs.h b/lib/c++defs.h
index 8ad46951ad4..458c014de5c 100644
--- a/lib/c++defs.h
+++ b/lib/c++defs.h
@@ -99,6 +99,12 @@
    Example:
      _GL_FUNCDECL_RPL (open, int, (const char *filename, int flags, ...)
                                   _GL_ARG_NONNULL ((1)));
+
+   Note: Attributes, such as _GL_ATTRIBUTE_DEPRECATED, are supported in front
+   of a _GL_FUNCDECL_RPL invocation only in C mode, not in C++ mode.  (That's
+   because
+     [[...]] extern "C" <declaration>;
+   is invalid syntax in C++.)
  */
 #define _GL_FUNCDECL_RPL(func,rettype,parameters_and_attributes) \
   _GL_FUNCDECL_RPL_1 (rpl_##func, rettype, parameters_and_attributes)
diff --git a/lib/c-ctype.h b/lib/c-ctype.h
index 35ca83d7d43..cb0f4f3ba1f 100644
--- a/lib/c-ctype.h
+++ b/lib/c-ctype.h
@@ -23,9 +23,11 @@
 #ifndef C_CTYPE_H
 #define C_CTYPE_H
 
-#ifndef _GL_INLINE_HEADER_BEGIN
+/* This file uses _GL_INLINE_HEADER_BEGIN, _GL_INLINE.  */
+#if !_GL_CONFIG_H_INCLUDED
  #error "Please include config.h first."
 #endif
+
 _GL_INLINE_HEADER_BEGIN
 #ifndef C_CTYPE_INLINE
 # define C_CTYPE_INLINE _GL_INLINE
diff --git a/lib/c-strcase.h b/lib/c-strcase.h
index 9bcca01b27c..5dfa96c41f4 100644
--- a/lib/c-strcase.h
+++ b/lib/c-strcase.h
@@ -18,6 +18,11 @@
 #ifndef C_STRCASE_H
 #define C_STRCASE_H
 
+/* This file uses _GL_ATTRIBUTE_PURE.  */
+#if !_GL_CONFIG_H_INCLUDED
+ #error "Please include config.h first."
+#endif
+
 #include <stddef.h>
 
 
diff --git a/lib/careadlinkat.h b/lib/careadlinkat.h
index 201d0415fff..562cf013b75 100644
--- a/lib/careadlinkat.h
+++ b/lib/careadlinkat.h
@@ -20,6 +20,11 @@
 #ifndef _GL_CAREADLINKAT_H
 #define _GL_CAREADLINKAT_H
 
+/* This file uses HAVE_READLINKAT.  */
+#if !_GL_CONFIG_H_INCLUDED
+ #error "Please include config.h first."
+#endif
+
 #include <fcntl.h>
 #include <unistd.h>
 
diff --git a/lib/count-leading-zeros.h b/lib/count-leading-zeros.h
index 99151d695bf..9fe2a03ee09 100644
--- a/lib/count-leading-zeros.h
+++ b/lib/count-leading-zeros.h
@@ -19,12 +19,14 @@
 #ifndef COUNT_LEADING_ZEROS_H
 #define COUNT_LEADING_ZEROS_H 1
 
+/* This file uses _GL_INLINE_HEADER_BEGIN, _GL_INLINE.  */
+#if !_GL_CONFIG_H_INCLUDED
+ #error "Please include config.h first."
+#endif
+
 #include <limits.h>
 #include <stdlib.h>
 
-#ifndef _GL_INLINE_HEADER_BEGIN
- #error "Please include config.h first."
-#endif
 _GL_INLINE_HEADER_BEGIN
 #ifndef COUNT_LEADING_ZEROS_INLINE
 # define COUNT_LEADING_ZEROS_INLINE _GL_INLINE
diff --git a/lib/count-one-bits.h b/lib/count-one-bits.h
index 01a60b77b85..2821a1fb75e 100644
--- a/lib/count-one-bits.h
+++ b/lib/count-one-bits.h
@@ -19,12 +19,14 @@
 #ifndef COUNT_ONE_BITS_H
 #define COUNT_ONE_BITS_H 1
 
+/* This file uses _GL_INLINE_HEADER_BEGIN, _GL_INLINE.  */
+#if !_GL_CONFIG_H_INCLUDED
+ #error "Please include config.h first."
+#endif
+
 #include <limits.h>
 #include <stdlib.h>
 
-#ifndef _GL_INLINE_HEADER_BEGIN
- #error "Please include config.h first."
-#endif
 _GL_INLINE_HEADER_BEGIN
 #ifndef COUNT_ONE_BITS_INLINE
 # define COUNT_ONE_BITS_INLINE _GL_INLINE
diff --git a/lib/count-trailing-zeros.h b/lib/count-trailing-zeros.h
index ef8e164126a..9b33df76f6d 100644
--- a/lib/count-trailing-zeros.h
+++ b/lib/count-trailing-zeros.h
@@ -19,12 +19,14 @@
 #ifndef COUNT_TRAILING_ZEROS_H
 #define COUNT_TRAILING_ZEROS_H 1
 
+/* This file uses _GL_INLINE_HEADER_BEGIN, _GL_INLINE.  */
+#if !_GL_CONFIG_H_INCLUDED
+ #error "Please include config.h first."
+#endif
+
 #include <limits.h>
 #include <stdlib.h>
 
-#ifndef _GL_INLINE_HEADER_BEGIN
- #error "Please include config.h first."
-#endif
 _GL_INLINE_HEADER_BEGIN
 #ifndef COUNT_TRAILING_ZEROS_INLINE
 # define COUNT_TRAILING_ZEROS_INLINE _GL_INLINE
diff --git a/lib/dirent-private.h b/lib/dirent-private.h
new file mode 100644
index 00000000000..012b6837198
--- /dev/null
+++ b/lib/dirent-private.h
@@ -0,0 +1,67 @@
+/* Private details of the DIR type.
+   Copyright (C) 2011-2023 Free Software Foundation, Inc.
+
+   This file is free software: you can redistribute it and/or modify
+   it under the terms of the GNU Lesser General Public License as
+   published by the Free Software Foundation; either version 2.1 of the
+   License, or (at your option) any later version.
+
+   This file is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+#ifndef _DIRENT_PRIVATE_H
+#define _DIRENT_PRIVATE_H 1
+
+#if HAVE_DIRENT_H                       /* mingw */
+
+# undef DIR
+
+struct gl_directory
+{
+  /* File descriptor to close during closedir().
+     Needed for implementing fdopendir().  */
+  int fd_to_close;
+  /* Pointer to the real DIR.  */
+  DIR *real_dirp;
+};
+
+/* Restore definition from dirent.h.  */
+# define DIR struct gl_directory
+
+#else                                   /* MSVC */
+
+# define WIN32_LEAN_AND_MEAN
+# include <windows.h>
+
+/* Don't assume that UNICODE is not defined.  */
+# undef WIN32_FIND_DATA
+# define WIN32_FIND_DATA WIN32_FIND_DATAA
+
+struct gl_directory
+{
+  /* File descriptor to close during closedir().
+     Needed for implementing fdopendir().  */
+  int fd_to_close;
+  /* Status, or error code to produce in next readdir() call.
+     -2 means the end of the directory is already reached,
+     -1 means the entry was already filled by FindFirstFile,
+     0 means the entry needs to be filled using FindNextFile.
+     A positive value is an error code.  */
+  int status;
+  /* Handle, reading the directory, at current position.  */
+  HANDLE current;
+  /* Found directory entry.  */
+  WIN32_FIND_DATA entry;
+  /* Argument to pass to FindFirstFile.  It consists of the absolutized
+     directory name, followed by a directory separator and the wildcards.  */
+  char dir_name_mask[1];
+};
+
+#endif
+
+#endif /* _DIRENT_PRIVATE_H */
diff --git a/lib/dirent.in.h b/lib/dirent.in.h
index 2aaabd054a8..d409a031ec8 100644
--- a/lib/dirent.in.h
+++ b/lib/dirent.in.h
@@ -29,6 +29,12 @@
 #ifndef _@GUARD_PREFIX@_DIRENT_H
 #define _@GUARD_PREFIX@_DIRENT_H
 
+/* This file uses _GL_ATTRIBUTE_DEALLOC, _GL_ATTRIBUTE_MALLOC,
+   _GL_ATTRIBUTE_PURE, GNULIB_POSIXCHECK, HAVE_RAW_DECL_*.  */
+#if !_GL_CONFIG_H_INCLUDED
+ #error "Please include config.h first."
+#endif
+
 /* Get ino_t.  Needed on some systems, including glibc 2.8.  */
 #include <sys/types.h>
 
@@ -50,11 +56,24 @@ struct dirent
 #  define DT_LNK    10          /* symbolic link */
 #  define DT_SOCK   12          /* socket */
 #  define DT_WHT    14          /* whiteout */
-typedef struct gl_directory DIR;
 #  define GNULIB_defined_struct_dirent 1
 # endif
 #endif
 
+#if !@DIR_HAS_FD_MEMBER@
+# if !GNULIB_defined_DIR
+/* struct gl_directory is a type with a field 'int fd_to_close'.
+   It is needed for implementing fdopendir().  */
+struct gl_directory;
+#  if @HAVE_DIRENT_H@
+#   define DIR struct gl_directory
+#  else
+typedef struct gl_directory DIR;
+#  endif
+#  define GNULIB_defined_DIR 1
+# endif
+#endif
+
 /* _GL_ATTRIBUTE_DEALLOC (F, I) declares that the function returns pointers
    that can be freed by passing them as the Ith argument to the
    function F.  */
@@ -143,7 +162,7 @@ _GL_CXXALIAS_SYS (opendir, DIR *, (const char *dir_name));
 # endif
 _GL_CXXALIASWARN (opendir);
 #else
-# if @GNULIB_CLOSEDIR@ && __GNUC__ >= 11 && !defined opendir
+# if @GNULIB_CLOSEDIR@ && !GNULIB_defined_DIR && __GNUC__ >= 11 && !defined opendir
 /* For -Wmismatched-dealloc: Associate opendir with closedir or
    rpl_closedir.  */
 _GL_FUNCDECL_SYS (opendir, DIR *,
@@ -161,10 +180,19 @@ _GL_WARN_ON_USE (opendir, "opendir is not portable - "
 #endif
 
 #if @GNULIB_READDIR@
-# if !@HAVE_READDIR@
+# if @REPLACE_READDIR@
+#  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
+#   undef readdir
+#   define readdir rpl_readdir
+#  endif
+_GL_FUNCDECL_RPL (readdir, struct dirent *, (DIR *dirp) _GL_ARG_NONNULL ((1)));
+_GL_CXXALIAS_RPL (readdir, struct dirent *, (DIR *dirp));
+# else
+#  if !@HAVE_READDIR@
 _GL_FUNCDECL_SYS (readdir, struct dirent *, (DIR *dirp) _GL_ARG_NONNULL ((1)));
-# endif
+#  endif
 _GL_CXXALIAS_SYS (readdir, struct dirent *, (DIR *dirp));
+# endif
 _GL_CXXALIASWARN (readdir);
 #elif defined GNULIB_POSIXCHECK
 # undef readdir
@@ -175,10 +203,19 @@ _GL_WARN_ON_USE (readdir, "readdir is not portable - "
 #endif
 
 #if @GNULIB_REWINDDIR@
-# if !@HAVE_REWINDDIR@
+# if @REPLACE_REWINDDIR@
+#  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
+#   undef rewinddir
+#   define rewinddir rpl_rewinddir
+#  endif
+_GL_FUNCDECL_RPL (rewinddir, void, (DIR *dirp) _GL_ARG_NONNULL ((1)));
+_GL_CXXALIAS_RPL (rewinddir, void, (DIR *dirp));
+# else
+#  if !@HAVE_REWINDDIR@
 _GL_FUNCDECL_SYS (rewinddir, void, (DIR *dirp) _GL_ARG_NONNULL ((1)));
-# endif
+#  endif
 _GL_CXXALIAS_SYS (rewinddir, void, (DIR *dirp));
+# endif
 _GL_CXXALIASWARN (rewinddir);
 #elif defined GNULIB_POSIXCHECK
 # undef rewinddir
diff --git a/lib/dirfd.c b/lib/dirfd.c
index b2b1d25cdbd..75b2163c353 100644
--- a/lib/dirfd.c
+++ b/lib/dirfd.c
@@ -22,6 +22,10 @@
 #include <dirent.h>
 #include <errno.h>
 
+#if GNULIB_defined_DIR
+# include "dirent-private.h"
+#endif
+
 #ifdef __KLIBC__
 # include <stdlib.h>
 # include <io.h>
@@ -78,11 +82,17 @@ _gl_unregister_dirp_fd (int fd)
 int
 dirfd (DIR *dir_p)
 {
+#if GNULIB_defined_DIR
+  int fd = dir_p->fd_to_close;
+  if (fd == -1)
+    errno = EINVAL;
+  return fd;
+#else
   int fd = DIR_TO_FD (dir_p);
   if (fd == -1)
-#ifndef __KLIBC__
+# ifndef __KLIBC__
     errno = ENOTSUP;
-#else
+# else
     {
       struct dirp_fd_list *dirp_fd;
 
@@ -92,7 +102,8 @@ dirfd (DIR *dir_p)
 
       errno = EINVAL;
     }
-#endif
+# endif
 
   return fd;
+#endif
 }
diff --git a/lib/eloop-threshold.h b/lib/eloop-threshold.h
index 510f261795d..d9b154e4868 100644
--- a/lib/eloop-threshold.h
+++ b/lib/eloop-threshold.h
@@ -19,6 +19,11 @@
 #ifndef _ELOOP_THRESHOLD_H
 #define _ELOOP_THRESHOLD_H      1
 
+/* This file uses _GL_ATTRIBUTE_CONST.  */
+#if !_LIBC && !_GL_CONFIG_H_INCLUDED
+ #error "Please include config.h first."
+#endif
+
 #include <limits.h>
 #ifdef _LIBC
 # include <sys/param.h>
diff --git a/lib/execinfo.in.h b/lib/execinfo.in.h
index ff9293b6327..56b04d1d862 100644
--- a/lib/execinfo.in.h
+++ b/lib/execinfo.in.h
@@ -20,9 +20,11 @@
 #ifndef _GL_EXECINFO_H
 #define _GL_EXECINFO_H
 
-#ifndef _GL_INLINE_HEADER_BEGIN
+/* This file uses _GL_INLINE_HEADER_BEGIN, _GL_INLINE.  */
+#if !_GL_CONFIG_H_INCLUDED
  #error "Please include config.h first."
 #endif
+
 _GL_INLINE_HEADER_BEGIN
 #ifndef _GL_EXECINFO_INLINE
 # define _GL_EXECINFO_INLINE _GL_INLINE
diff --git a/lib/fcntl.in.h b/lib/fcntl.in.h
index e034eaf9f5a..d0bb85f30b5 100644
--- a/lib/fcntl.in.h
+++ b/lib/fcntl.in.h
@@ -74,6 +74,11 @@
 #ifndef _@GUARD_PREFIX@_FCNTL_H
 #define _@GUARD_PREFIX@_FCNTL_H
 
+/* This file uses GNULIB_POSIXCHECK, HAVE_RAW_DECL_*.  */
+#if !_GL_CONFIG_H_INCLUDED
+ #error "Please include config.h first."
+#endif
+
 #ifndef __GLIBC__ /* Avoid namespace pollution on glibc systems.  */
 # include <unistd.h>
 #endif
diff --git a/lib/fdopendir.c b/lib/fdopendir.c
index aa841e3e819..0f43d6ff349 100644
--- a/lib/fdopendir.c
+++ b/lib/fdopendir.c
@@ -25,44 +25,27 @@
 
 #if !HAVE_FDOPENDIR
 
-# include "openat.h"
-# include "openat-priv.h"
-# include "save-cwd.h"
+# if GNULIB_defined_DIR
+/* We are in control of the file descriptor of a DIR.  */
 
-# if GNULIB_DIRENT_SAFER
-#  include "dirent--.h"
-# endif
-
-# ifndef REPLACE_FCHDIR
-#  define REPLACE_FCHDIR 0
-# endif
-
-static DIR *fdopendir_with_dup (int, int, struct saved_cwd const *);
-static DIR *fd_clone_opendir (int, struct saved_cwd const *);
-
-/* Replacement for POSIX fdopendir.
+#  include "dirent-private.h"
 
-   First, try to simulate it via opendir ("/proc/self/fd/...").  Failing
-   that, simulate it by using fchdir metadata, or by doing
-   save_cwd/fchdir/opendir(".")/restore_cwd.
-   If either the save_cwd or the restore_cwd fails (relatively unlikely),
-   then give a diagnostic and exit nonzero.
-
-   If successful, the resulting stream is based on FD in
-   implementations where streams are based on file descriptors and in
-   applications where no other thread or signal handler allocates or
-   frees file descriptors.  In other cases, consult dirfd on the result
-   to find out whether FD is still being used.
+#  if !REPLACE_FCHDIR
+#   error "unexpected configuration: GNULIB_defined_DIR but fchdir not replaced"
+#  endif
 
-   Otherwise, this function works just like POSIX fdopendir.
+DIR *
+fdopendir (int fd)
+{
+  char const *name = _gl_directory_name (fd);
+  DIR *dirp = name ? opendir (name) : NULL;
+  if (dirp != NULL)
+    dirp->fd_to_close = fd;
+  return dirp;
+}
 
-   W A R N I N G:
+# elif defined __KLIBC__
 
-   Unlike other fd-related functions, this one places constraints on FD.
-   If this function returns successfully, FD is under control of the
-   dirent.h system, and the caller should not close or modify the state of
-   FD other than by the dirent.h functions.  */
-# ifdef __KLIBC__
 #  include <InnoTekLIBC/backend.h>
 
 DIR *
@@ -96,7 +79,48 @@ fdopendir (int fd)
 
   return dirp;
 }
+
 # else
+/* We are not in control of the file descriptor of a DIR, and therefore have to
+   play tricks with file descriptors before and after a call to opendir().  */
+
+#  include "openat.h"
+#  include "openat-priv.h"
+#  include "save-cwd.h"
+
+#  if GNULIB_DIRENT_SAFER
+#   include "dirent--.h"
+#  endif
+
+#  ifndef REPLACE_FCHDIR
+#   define REPLACE_FCHDIR 0
+#  endif
+
+static DIR *fdopendir_with_dup (int, int, struct saved_cwd const *);
+static DIR *fd_clone_opendir (int, struct saved_cwd const *);
+
+/* Replacement for POSIX fdopendir.
+
+   First, try to simulate it via opendir ("/proc/self/fd/...").  Failing
+   that, simulate it by using fchdir metadata, or by doing
+   save_cwd/fchdir/opendir(".")/restore_cwd.
+   If either the save_cwd or the restore_cwd fails (relatively unlikely),
+   then give a diagnostic and exit nonzero.
+
+   If successful, the resulting stream is based on FD in
+   implementations where streams are based on file descriptors and in
+   applications where no other thread or signal handler allocates or
+   frees file descriptors.  In other cases, consult dirfd on the result
+   to find out whether FD is still being used.
+
+   Otherwise, this function works just like POSIX fdopendir.
+
+   W A R N I N G:
+
+   Unlike other fd-related functions, this one places constraints on FD.
+   If this function returns successfully, FD is under control of the
+   dirent.h system, and the caller should not close or modify the state of
+   FD other than by the dirent.h functions.  */
 DIR *
 fdopendir (int fd)
 {
@@ -119,7 +143,6 @@ fdopendir (int fd)
 
   return dir;
 }
-# endif
 
 /* Like fdopendir, except that if OLDER_DUPFD is not -1, it is known
    to be a dup of FD which is less than FD - 1 and which will be
@@ -188,7 +211,7 @@ fd_clone_opendir (int fd, struct saved_cwd const *cwd)
           if (proc_file != buf)
             free (proc_file);
         }
-# if REPLACE_FCHDIR
+#  if REPLACE_FCHDIR
       if (! dir && EXPECTED_ERRNO (saved_errno))
         {
           char const *name = _gl_directory_name (fd);
@@ -203,7 +226,7 @@ fd_clone_opendir (int fd, struct saved_cwd const *cwd)
 
           return dp;
         }
-# endif
+#  endif
       errno = saved_errno;
       return dir;
     }
@@ -223,6 +246,8 @@ fd_clone_opendir (int fd, struct saved_cwd const *cwd)
     }
 }
 
+# endif
+
 #else /* HAVE_FDOPENDIR */
 
 # include <errno.h>
diff --git a/lib/file-has-acl.c b/lib/file-has-acl.c
index b31a2ea2523..38bc806dc49 100644
--- a/lib/file-has-acl.c
+++ b/lib/file-has-acl.c
@@ -29,7 +29,7 @@
 
 #include "acl-internal.h"
 
-#if USE_ACL && GETXATTR_WITH_POSIX_ACLS
+#if USE_ACL && HAVE_LINUX_XATTR_H && HAVE_LISTXATTR
 # include <string.h>
 # include <arpa/inet.h>
 # include <sys/xattr.h>
@@ -44,6 +44,20 @@ enum {
   ACE4_IDENTIFIER_GROUP        = 0x00000040
 };
 
+/* Return true if ATTR is in the set represented by the NUL-terminated
+   strings in LISTBUF, which is of size LISTSIZE.  */
+
+static bool
+have_xattr (char const *attr, char const *listbuf, ssize_t listsize)
+{
+  char const *blim = listbuf + listsize;
+  for (char const *b = listbuf; b < blim; b += strlen (b) + 1)
+    for (char const *a = attr; *a == *b; a++, b++)
+      if (!*a)
+        return true;
+  return false;
+}
+
 /* Return 1 if given ACL in XDR format is non-trivial, 0 if it is trivial.
    -1 upon failure to determine it.  Possibly change errno.  Assume that
    the ACL is valid, except avoid undefined behavior even if invalid.
@@ -137,37 +151,65 @@ file_has_acl (char const *name, struct stat const *sb)
   if (! S_ISLNK (sb->st_mode))
     {
 
-# if GETXATTR_WITH_POSIX_ACLS
-
-      ssize_t ret;
+# if HAVE_LINUX_XATTR_H && HAVE_LISTXATTR
       int initial_errno = errno;
 
-      ret = getxattr (name, XATTR_NAME_POSIX_ACL_ACCESS, NULL, 0);
-      if (ret < 0 && errno == ENODATA)
-        ret = 0;
-      else if (ret > 0)
-        return 1;
-
-      if (ret == 0 && S_ISDIR (sb->st_mode))
+      /* The max length of a trivial NFSv4 ACL is 6 words for owner,
+         6 for group, 7 for everyone, all times 2 because there are
+         both allow and deny ACEs.  There are 6 words for owner
+         because of type, flag, mask, wholen, "OWNER@"+pad and
+         similarly for group; everyone is another word to hold
+         "EVERYONE@".  */
+      typedef uint32_t trivial_NFSv4_xattr_buf[2 * (6 + 6 + 7)];
+
+      /* A buffer large enough to hold any trivial NFSv4 ACL,
+         and also useful as a small array of char.  */
+      union {
+        trivial_NFSv4_xattr_buf xattr;
+        char ch[sizeof (trivial_NFSv4_xattr_buf)];
+      } stackbuf;
+
+      char *listbuf = stackbuf.ch;
+      ssize_t listbufsize = sizeof stackbuf.ch;
+      char *heapbuf = NULL;
+      ssize_t listsize;
+
+      /* Use listxattr first, as this means just one syscall in the
+         typical case where the file lacks an ACL.  Try stackbuf
+         first, falling back on malloc if stackbuf is too small.  */
+      while ((listsize = listxattr (name, listbuf, listbufsize)) < 0
+             && errno == ERANGE)
         {
-          ret = getxattr (name, XATTR_NAME_POSIX_ACL_DEFAULT, NULL, 0);
-          if (ret < 0 && errno == ENODATA)
-            ret = 0;
-          else if (ret > 0)
-            return 1;
+          free (heapbuf);
+          listbufsize = listxattr (name, NULL, 0);
+          if (listbufsize < 0)
+            return -1;
+          if (SIZE_MAX < listbufsize)
+            {
+              errno = ENOMEM;
+              return -1;
+            }
+          listbuf = heapbuf = malloc (listbufsize);
+          if (!listbuf)
+            return -1;
         }
 
-      if (ret < 0)
+      int ret
+        = (listsize < 0 ? -1
+           : (have_xattr (XATTR_NAME_POSIX_ACL_ACCESS, listbuf, listsize)
+              || (S_ISDIR (sb->st_mode)
+                  && have_xattr (XATTR_NAME_POSIX_ACL_DEFAULT,
+                                 listbuf, listsize))));
+      bool nfsv4_acl_but_no_posix_acl
+        = ret == 0 && have_xattr (XATTR_NAME_NFSV4_ACL, listbuf, listsize);
+      free (heapbuf);
+
+      /* If there is an NFSv4 ACL but no POSIX ACL, follow up with a
+         getxattr syscall to see whether the NFSv4 ACL is nontrivial.  */
+      if (nfsv4_acl_but_no_posix_acl)
         {
-          /* Check for NFSv4 ACLs.  The max length of a trivial
-             ACL is 6 words for owner, 6 for group, 7 for everyone,
-             all times 2 because there are both allow and deny ACEs.
-             There are 6 words for owner because of type, flag, mask,
-             wholen, "OWNER@"+pad and similarly for group; everyone is
-             another word to hold "EVERYONE@".  */
-          uint32_t xattr[2 * (6 + 6 + 7)];
-
-          ret = getxattr (name, XATTR_NAME_NFSV4_ACL, xattr, sizeof xattr);
+          ret = getxattr (name, XATTR_NAME_NFSV4_ACL,
+                          stackbuf.xattr, sizeof stackbuf.xattr);
           if (ret < 0)
             switch (errno)
               {
@@ -177,7 +219,7 @@ file_has_acl (char const *name, struct stat const *sb)
           else
             {
               /* It looks like a trivial ACL, but investigate further.  */
-              ret = acl_nfs4_nontrivial (xattr, ret);
+              ret = acl_nfs4_nontrivial (stackbuf.xattr, ret);
               if (ret < 0)
                 {
                   errno = EINVAL;
diff --git a/lib/filemode.h b/lib/filemode.h
index 15a8dcc3760..3e1d9903eac 100644
--- a/lib/filemode.h
+++ b/lib/filemode.h
@@ -17,6 +17,12 @@
    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
 
 #ifndef FILEMODE_H_
+# define FILEMODE_H_
+
+/* This file uses HAVE_DECL_STRMODE.  */
+# if !_GL_CONFIG_H_INCLUDED
+#  error "Please include config.h first."
+# endif
 
 # include <sys/types.h>
 # include <sys/stat.h>
diff --git a/lib/filevercmp.h b/lib/filevercmp.h
index 6b81ab32a7f..9e052bdd08c 100644
--- a/lib/filevercmp.h
+++ b/lib/filevercmp.h
@@ -20,6 +20,11 @@
 #ifndef FILEVERCMP_H
 #define FILEVERCMP_H
 
+/* This file uses _GL_ATTRIBUTE_PURE.  */
+#if !_GL_CONFIG_H_INCLUDED
+ #error "Please include config.h first."
+#endif
+
 #include <stddef.h>
 
 /* Compare strings A and B as file names containing version numbers,
diff --git a/lib/flexmember.h b/lib/flexmember.h
index a6cc876a6d5..8c5915ecf9c 100644
--- a/lib/flexmember.h
+++ b/lib/flexmember.h
@@ -20,6 +20,11 @@
 
    Written by Paul Eggert.  */
 
+/* This file uses _Alignof.  */
+#if !_GL_CONFIG_H_INCLUDED
+ #error "Please include config.h first."
+#endif
+
 #include <stddef.h>
 
 /* Nonzero multiple of alignment of TYPE, suitable for FLEXSIZEOF below.
diff --git a/lib/fpending.h b/lib/fpending.h
index 5e860db6810..1604ca0b7af 100644
--- a/lib/fpending.h
+++ b/lib/fpending.h
@@ -18,6 +18,12 @@
 
    Written by Jim Meyering.  */
 
+/* This file uses _GL_ATTRIBUTE_PURE, HAVE_STDIO_EXT_H,
+   HAVE_DECL___FPENDING.  */
+#if !_GL_CONFIG_H_INCLUDED
+ #error "Please include config.h first."
+#endif
+
 #include <stddef.h>
 #include <stdio.h>
 #if HAVE_STDIO_EXT_H
diff --git a/lib/gnulib.mk.in b/lib/gnulib.mk.in
index 47d08a5e27f..29861a31d12 100644
--- a/lib/gnulib.mk.in
+++ b/lib/gnulib.mk.in
@@ -221,6 +221,7 @@ DBUS_LIBS = @DBUS_LIBS@
 DBUS_OBJ = @DBUS_OBJ@
 DEFS = @DEFS@
 DESLIB = @DESLIB@
+DIR_HAS_FD_MEMBER = @DIR_HAS_FD_MEMBER@
 DOCMISC_W32 = @DOCMISC_W32@
 DUMPING = @DUMPING@
 DYNAMIC_LIB_SECONDARY_SUFFIX = @DYNAMIC_LIB_SECONDARY_SUFFIX@
@@ -444,6 +445,7 @@ GL_GNULIB_MBSSEP = @GL_GNULIB_MBSSEP@
 GL_GNULIB_MBSSPN = @GL_GNULIB_MBSSPN@
 GL_GNULIB_MBSSTR = @GL_GNULIB_MBSSTR@
 GL_GNULIB_MBSTOK_R = @GL_GNULIB_MBSTOK_R@
+GL_GNULIB_MBSTOWCS = @GL_GNULIB_MBSTOWCS@
 GL_GNULIB_MBTOWC = @GL_GNULIB_MBTOWC@
 GL_GNULIB_MDA_ACCESS = @GL_GNULIB_MDA_ACCESS@
 GL_GNULIB_MDA_CHDIR = @GL_GNULIB_MDA_CHDIR@
@@ -689,6 +691,7 @@ HAVE_DECL_MEMMEM = @HAVE_DECL_MEMMEM@
 HAVE_DECL_MEMRCHR = @HAVE_DECL_MEMRCHR@
 HAVE_DECL_OBSTACK_PRINTF = @HAVE_DECL_OBSTACK_PRINTF@
 HAVE_DECL_POSIX_SPAWN_SETSID = @HAVE_DECL_POSIX_SPAWN_SETSID@
+HAVE_DECL_PROGRAM_INVOCATION_NAME = @HAVE_DECL_PROGRAM_INVOCATION_NAME@
 HAVE_DECL_PUTW = @HAVE_DECL_PUTW@
 HAVE_DECL_SETENV = @HAVE_DECL_SETENV@
 HAVE_DECL_SETHOSTNAME = @HAVE_DECL_SETHOSTNAME@
@@ -956,6 +959,7 @@ LIB_WSOCK32 = @LIB_WSOCK32@
 LIB_XATTR = @LIB_XATTR@
 LIMITS_H = @LIMITS_H@
 LN_S_FILEONLY = @LN_S_FILEONLY@
+LOCALE_FR_UTF8 = @LOCALE_FR_UTF8@
 LTLIBGMP = @LTLIBGMP@
 LTLIBINTL = @LTLIBINTL@
 LTLIBOBJS = @LTLIBOBJS@
@@ -1127,7 +1131,9 @@ REPLACE_LSEEK = @REPLACE_LSEEK@
 REPLACE_LSTAT = @REPLACE_LSTAT@
 REPLACE_MALLOC_FOR_MALLOC_GNU = @REPLACE_MALLOC_FOR_MALLOC_GNU@
 REPLACE_MALLOC_FOR_MALLOC_POSIX = @REPLACE_MALLOC_FOR_MALLOC_POSIX@
+REPLACE_MBSTOWCS = @REPLACE_MBSTOWCS@
 REPLACE_MBTOWC = @REPLACE_MBTOWC@
+REPLACE_MB_CUR_MAX = @REPLACE_MB_CUR_MAX@
 REPLACE_MEMCHR = @REPLACE_MEMCHR@
 REPLACE_MEMMEM = @REPLACE_MEMMEM@
 REPLACE_MEMPCPY = @REPLACE_MEMPCPY@
@@ -1164,6 +1170,7 @@ REPLACE_RAISE = @REPLACE_RAISE@
 REPLACE_RANDOM = @REPLACE_RANDOM@
 REPLACE_RANDOM_R = @REPLACE_RANDOM_R@
 REPLACE_READ = @REPLACE_READ@
+REPLACE_READDIR = @REPLACE_READDIR@
 REPLACE_READLINK = @REPLACE_READLINK@
 REPLACE_READLINKAT = @REPLACE_READLINKAT@
 REPLACE_REALLOCARRAY = @REPLACE_REALLOCARRAY@
@@ -1173,6 +1180,7 @@ REPLACE_REALPATH = @REPLACE_REALPATH@
 REPLACE_REMOVE = @REPLACE_REMOVE@
 REPLACE_RENAME = @REPLACE_RENAME@
 REPLACE_RENAMEAT = @REPLACE_RENAMEAT@
+REPLACE_REWINDDIR = @REPLACE_REWINDDIR@
 REPLACE_RMDIR = @REPLACE_RMDIR@
 REPLACE_SELECT = @REPLACE_SELECT@
 REPLACE_SETENV = @REPLACE_SETENV@
@@ -1732,6 +1740,7 @@ dirent.h: dirent.in.h $(top_builddir)/config.status $(CXXDEFS_H) $(ARG_NONNULL_H
 	      -e 's|@''PRAGMA_SYSTEM_HEADER''@|@PRAGMA_SYSTEM_HEADER@|g' \
 	      -e 's|@''PRAGMA_COLUMNS''@|@PRAGMA_COLUMNS@|g' \
 	      -e 's|@''NEXT_DIRENT_H''@|$(NEXT_DIRENT_H)|g' \
+	      -e 's/@''DIR_HAS_FD_MEMBER''@/$(DIR_HAS_FD_MEMBER)/g' \
 	      -e 's/@''GNULIB_OPENDIR''@/$(GL_GNULIB_OPENDIR)/g' \
 	      -e 's/@''GNULIB_READDIR''@/$(GL_GNULIB_READDIR)/g' \
 	      -e 's/@''GNULIB_REWINDDIR''@/$(GL_GNULIB_REWINDDIR)/g' \
@@ -1750,6 +1759,8 @@ dirent.h: dirent.in.h $(top_builddir)/config.status $(CXXDEFS_H) $(ARG_NONNULL_H
 	      -e 's|@''HAVE_SCANDIR''@|$(HAVE_SCANDIR)|g' \
 	      -e 's|@''HAVE_ALPHASORT''@|$(HAVE_ALPHASORT)|g' \
 	      -e 's|@''REPLACE_OPENDIR''@|$(REPLACE_OPENDIR)|g' \
+	      -e 's|@''REPLACE_READDIR''@|$(REPLACE_READDIR)|g' \
+	      -e 's|@''REPLACE_REWINDDIR''@|$(REPLACE_REWINDDIR)|g' \
 	      -e 's|@''REPLACE_CLOSEDIR''@|$(REPLACE_CLOSEDIR)|g' \
 	      -e 's|@''REPLACE_DIRFD''@|$(REPLACE_DIRFD)|g' \
 	      -e 's|@''REPLACE_FDOPENDIR''@|$(REPLACE_FDOPENDIR)|g' \
@@ -1774,6 +1785,8 @@ libgnu_a_SOURCES += dirfd.c
 endif
 
 endif
+EXTRA_DIST += dirent-private.h
+
 endif
 ## end   gnulib module dirfd
 
@@ -1974,6 +1987,8 @@ ifneq (,$(GL_COND_OBJ_FDOPENDIR_CONDITION))
 libgnu_a_SOURCES += fdopendir.c
 endif
 
+EXTRA_DIST += dirent-private.h
+
 endif
 ## end   gnulib module fdopendir
 
@@ -3209,6 +3224,7 @@ stdlib.h: stdlib.in.h $(top_builddir)/config.status $(CXXDEFS_H) \
 	      -e 's/@''GNULIB_GRANTPT''@/$(GL_GNULIB_GRANTPT)/g' \
 	      -e 's/@''GNULIB_MALLOC_GNU''@/$(GL_GNULIB_MALLOC_GNU)/g' \
 	      -e 's/@''GNULIB_MALLOC_POSIX''@/$(GL_GNULIB_MALLOC_POSIX)/g' \
+	      -e 's/@''GNULIB_MBSTOWCS''@/$(GL_GNULIB_MBSTOWCS)/g' \
 	      -e 's/@''GNULIB_MBTOWC''@/$(GL_GNULIB_MBTOWC)/g' \
 	      -e 's/@''GNULIB_MKDTEMP''@/$(GL_GNULIB_MKDTEMP)/g' \
 	      -e 's/@''GNULIB_MKOSTEMP''@/$(GL_GNULIB_MKOSTEMP)/g' \
@@ -3254,6 +3270,7 @@ stdlib.h: stdlib.in.h $(top_builddir)/config.status $(CXXDEFS_H) \
 	      -e 's|@''HAVE_DECL_FCVT''@|$(HAVE_DECL_FCVT)|g' \
 	      -e 's|@''HAVE_DECL_GCVT''@|$(HAVE_DECL_GCVT)|g' \
 	      -e 's|@''HAVE_DECL_GETLOADAVG''@|$(HAVE_DECL_GETLOADAVG)|g' \
+	      -e 's|@''HAVE_DECL_PROGRAM_INVOCATION_NAME''@|$(HAVE_DECL_PROGRAM_INVOCATION_NAME)|g' \
 	      -e 's|@''HAVE_GETPROGNAME''@|$(HAVE_GETPROGNAME)|g' \
 	      -e 's|@''HAVE_GETSUBOPT''@|$(HAVE_GETSUBOPT)|g' \
 	      -e 's|@''HAVE_GRANTPT''@|$(HAVE_GRANTPT)|g' \
@@ -3302,6 +3319,8 @@ stdlib.h: stdlib.in.h $(top_builddir)/config.status $(CXXDEFS_H) \
 	      -e 's|@''REPLACE_INITSTATE''@|$(REPLACE_INITSTATE)|g' \
 	      -e 's|@''REPLACE_MALLOC_FOR_MALLOC_GNU''@|$(REPLACE_MALLOC_FOR_MALLOC_GNU)|g' \
 	      -e 's|@''REPLACE_MALLOC_FOR_MALLOC_POSIX''@|$(REPLACE_MALLOC_FOR_MALLOC_POSIX)|g' \
+	      -e 's|@''REPLACE_MB_CUR_MAX''@|$(REPLACE_MB_CUR_MAX)|g' \
+	      -e 's|@''REPLACE_MBSTOWCS''@|$(REPLACE_MBSTOWCS)|g' \
 	      -e 's|@''REPLACE_MBTOWC''@|$(REPLACE_MBTOWC)|g' \
 	      -e 's|@''REPLACE_MKOSTEMP''@|$(REPLACE_MKOSTEMP)|g' \
 	      -e 's|@''REPLACE_MKOSTEMPS''@|$(REPLACE_MKOSTEMPS)|g' \
diff --git a/lib/inttypes.in.h b/lib/inttypes.in.h
index 5b7ef12dc7e..22643876ab3 100644
--- a/lib/inttypes.in.h
+++ b/lib/inttypes.in.h
@@ -46,6 +46,11 @@
 #if ! defined INTTYPES_H && ! defined _GL_JUST_INCLUDE_SYSTEM_INTTYPES_H
 #define INTTYPES_H
 
+/* This file uses GNULIB_POSIXCHECK, HAVE_RAW_DECL_*.  */
+#if !_GL_CONFIG_H_INCLUDED
+ #error "Please include config.h first."
+#endif
+
 /* Include <stdint.h> or the gnulib replacement.
    But avoid namespace pollution on glibc systems.  */
 #ifndef __GLIBC__
diff --git a/lib/limits.in.h b/lib/limits.in.h
index a01b4c6a280..45d46fd6897 100644
--- a/lib/limits.in.h
+++ b/lib/limits.in.h
@@ -99,6 +99,11 @@
 # endif
 #endif
 
+/* Assume no multibyte character is longer than 16 bytes.  */
+#ifndef MB_LEN_MAX
+# define MB_LEN_MAX 16
+#endif
+
 /* Macros specified by C23 and by ISO/IEC TS 18661-1:2014.  */
 
 #if (! defined ULLONG_WIDTH                                             \
diff --git a/lib/malloc/dynarray_emplace_enlarge.c b/lib/malloc/dynarray_emplace_enlarge.c
index 7da539316c1..65aabb1e4a5 100644
--- a/lib/malloc/dynarray_emplace_enlarge.c
+++ b/lib/malloc/dynarray_emplace_enlarge.c
@@ -22,7 +22,7 @@
 
 #include <dynarray.h>
 #include <errno.h>
-#include <intprops.h>
+#include <stdckdint.h>
 #include <stdlib.h>
 #include <string.h>
 
@@ -56,7 +56,7 @@ __libc_dynarray_emplace_enlarge (struct dynarray_header *list,
     }
 
   size_t new_size;
-  if (INT_MULTIPLY_WRAPV (new_allocated, element_size, &new_size))
+  if (ckd_mul (&new_size, new_allocated, element_size))
     return false;
   void *new_array;
   if (list->array == scratch)
diff --git a/lib/malloc/dynarray_resize.c b/lib/malloc/dynarray_resize.c
index 7ecd4de63b9..014f98c330e 100644
--- a/lib/malloc/dynarray_resize.c
+++ b/lib/malloc/dynarray_resize.c
@@ -22,7 +22,7 @@
 
 #include <dynarray.h>
 #include <errno.h>
-#include <intprops.h>
+#include <stdckdint.h>
 #include <stdlib.h>
 #include <string.h>
 
@@ -42,7 +42,7 @@ __libc_dynarray_resize (struct dynarray_header *list, size_t size,
      over-allocation here.  */
 
   size_t new_size_bytes;
-  if (INT_MULTIPLY_WRAPV (size, element_size, &new_size_bytes))
+  if (ckd_mul (&new_size_bytes, size, element_size))
     {
       /* Overflow.  */
       __set_errno (ENOMEM);
diff --git a/lib/md5.h b/lib/md5.h
index f34e7cb8dfa..92dc6038988 100644
--- a/lib/md5.h
+++ b/lib/md5.h
@@ -20,6 +20,11 @@
 #ifndef _MD5_H
 #define _MD5_H 1
 
+/* This file uses HAVE_OPENSSL_MD5.  */
+#if !_GL_CONFIG_H_INCLUDED
+ #error "Please include config.h first."
+#endif
+
 #include <stdio.h>
 #include <stdint.h>
 
diff --git a/lib/minmax.h b/lib/minmax.h
index 1fbfc6616cf..0ac40198e24 100644
--- a/lib/minmax.h
+++ b/lib/minmax.h
@@ -23,6 +23,11 @@
    MIN, MAX macro redefinitions on some systems; the workaround is to
    #include this file as the last one among the #include list.  */
 
+/* This file uses HAVE_MINMAX_IN_LIMITS_H, HAVE_MINMAX_IN_SYS_PARAM_H.  */
+#if !_GL_CONFIG_H_INCLUDED
+ #error "Please include config.h first."
+#endif
+
 /* Before we define the following symbols we get the <limits.h> file
    since otherwise we get redefinitions on some systems if <limits.h> is
    included after this file.  Likewise for <sys/param.h>.
diff --git a/lib/mktime.c b/lib/mktime.c
index 94a4320e6ca..8e80bcdbd16 100644
--- a/lib/mktime.c
+++ b/lib/mktime.c
@@ -46,6 +46,7 @@
 #include <errno.h>
 #include <limits.h>
 #include <stdbool.h>
+#include <stdckdint.h>
 #include <stdlib.h>
 #include <string.h>
 
@@ -379,7 +380,7 @@ __mktime_internal (struct tm *tp,
   /* Invert CONVERT by probing.  First assume the same offset as last
      time.  */
 
-  INT_SUBTRACT_WRAPV (0, off, &negative_offset_guess);
+  ckd_sub (&negative_offset_guess, 0, off);
   long_int t0 = ydhms_diff (year, yday, hour, min, sec,
 			    EPOCH_YEAR - TM_YEAR_BASE, 0, 0, 0,
 			    negative_offset_guess);
@@ -465,7 +466,7 @@ __mktime_internal (struct tm *tp,
 	for (direction = -1; direction <= 1; direction += 2)
 	  {
 	    long_int ot;
-	    if (! INT_ADD_WRAPV (t, delta * direction, &ot))
+	    if (! ckd_add (&ot, t, delta * direction))
 	      {
 		struct tm otm;
 		if (! ranged_convert (convert, &ot, &otm))
@@ -503,8 +504,8 @@ __mktime_internal (struct tm *tp,
   /* Set *OFFSET to the low-order bits of T - T0 - NEGATIVE_OFFSET_GUESS.
      This is just a heuristic to speed up the next mktime call, and
      correctness is unaffected if integer overflow occurs here.  */
-  INT_SUBTRACT_WRAPV (t, t0, offset);
-  INT_SUBTRACT_WRAPV (*offset, negative_offset_guess, offset);
+  ckd_sub (offset, t, t0);
+  ckd_sub (offset, *offset, negative_offset_guess);
 
   if (LEAP_SECONDS_POSSIBLE && sec_requested != tm.tm_sec)
     {
@@ -513,7 +514,7 @@ __mktime_internal (struct tm *tp,
       long_int sec_adjustment = sec == 0 && tm.tm_sec == 60;
       sec_adjustment -= sec;
       sec_adjustment += sec_requested;
-      if (INT_ADD_WRAPV (t, sec_adjustment, &t)
+      if (ckd_add (&t, t, sec_adjustment)
 	  || ! (mktime_min <= t && t <= mktime_max))
 	{
 	  __set_errno (EOVERFLOW);
diff --git a/lib/openat.h b/lib/openat.h
index 37d8eedbee4..97f066d10f8 100644
--- a/lib/openat.h
+++ b/lib/openat.h
@@ -19,15 +19,18 @@
 #ifndef _GL_HEADER_OPENAT
 #define _GL_HEADER_OPENAT
 
+/* This file uses _GL_INLINE_HEADER_BEGIN, _GL_INLINE, _Noreturn,
+   _GL_ATTRIBUTE_DEPRECATED, HAVE_OPENAT.  */
+#if !_GL_CONFIG_H_INCLUDED
+ #error "Please include config.h first."
+#endif
+
 #include <fcntl.h>
 
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <unistd.h>
 
-#ifndef _GL_INLINE_HEADER_BEGIN
- #error "Please include config.h first."
-#endif
 _GL_INLINE_HEADER_BEGIN
 
 #if !HAVE_OPENAT
diff --git a/lib/pathmax.h b/lib/pathmax.h
index 0dd8f3bc5ce..6930283b82a 100644
--- a/lib/pathmax.h
+++ b/lib/pathmax.h
@@ -39,6 +39,11 @@
          #endif
  */
 
+/* This file uses HAVE_SYS_PARAM_H.  */
+# if !_GL_CONFIG_H_INCLUDED
+#  error "Please include config.h first."
+# endif
+
 # include <unistd.h>
 
 # include <limits.h>
diff --git a/lib/pselect.c b/lib/pselect.c
index f5d21e1048a..52d38378783 100644
--- a/lib/pselect.c
+++ b/lib/pselect.c
@@ -45,6 +45,12 @@ pselect (int nfds, fd_set *restrict rfds,
   sigset_t origmask;
   struct timeval tv, *tvp;
 
+  if (nfds < 0 || nfds > FD_SETSIZE)
+    {
+      errno = EINVAL;
+      return -1;
+    }
+
   if (timeout)
     {
       if (! (0 <= timeout->tv_nsec && timeout->tv_nsec < 1000000000))
diff --git a/lib/regex_internal.h b/lib/regex_internal.h
index 149ec2e868a..0270091df70 100644
--- a/lib/regex_internal.h
+++ b/lib/regex_internal.h
@@ -29,6 +29,7 @@
 #include <locale.h>
 #include <wchar.h>
 #include <wctype.h>
+#include <stdckdint.h>
 #include <stdint.h>
 
 #ifndef _LIBC
@@ -822,7 +823,7 @@ re_string_elem_size_at (const re_string_t *pstr, Idx idx)
 }
 
 #ifdef _LIBC
-# if __GNUC__ >= 7
+# if __glibc_has_attribute (__fallthrough__)
 #  define FALLTHROUGH __attribute__ ((__fallthrough__))
 # else
 #  define FALLTHROUGH ((void) 0)
diff --git a/lib/regexec.c b/lib/regexec.c
index 13e0349e727..f05f38ae0e0 100644
--- a/lib/regexec.c
+++ b/lib/regexec.c
@@ -324,7 +324,7 @@ re_search_2_stub (struct re_pattern_buffer *bufp, const char *string1,
   char *s = NULL;
 
   if (__glibc_unlikely ((length1 < 0 || length2 < 0 || stop < 0
-			 || INT_ADD_WRAPV (length1, length2, &len))))
+			 || ckd_add (&len, length1, length2))))
     return -2;
 
   /* Concatenate the strings.  */
diff --git a/lib/sha1.h b/lib/sha1.h
index 5a58b567ceb..854213a9211 100644
--- a/lib/sha1.h
+++ b/lib/sha1.h
@@ -19,6 +19,11 @@
 #ifndef SHA1_H
 # define SHA1_H 1
 
+/* This file uses HAVE_OPENSSL_SHA1.  */
+# if !_GL_CONFIG_H_INCLUDED
+#  error "Please include config.h first."
+# endif
+
 # include <stdio.h>
 # include <stdint.h>
 
diff --git a/lib/sha256.h b/lib/sha256.h
index 2879477e89c..938b1067062 100644
--- a/lib/sha256.h
+++ b/lib/sha256.h
@@ -18,6 +18,11 @@
 #ifndef SHA256_H
 # define SHA256_H 1
 
+/* This file uses HAVE_OPENSSL_SHA256.  */
+# if !_GL_CONFIG_H_INCLUDED
+#  error "Please include config.h first."
+# endif
+
 # include <stdio.h>
 # include <stdint.h>
 
diff --git a/lib/sha512.h b/lib/sha512.h
index e3a98a2644c..f3465bc8a68 100644
--- a/lib/sha512.h
+++ b/lib/sha512.h
@@ -18,6 +18,11 @@
 #ifndef SHA512_H
 # define SHA512_H 1
 
+/* This file uses HAVE_OPENSSL_SHA512.  */
+# if !_GL_CONFIG_H_INCLUDED
+#  error "Please include config.h first."
+# endif
+
 # include <stdio.h>
 # include "u64.h"
 
diff --git a/lib/signal.in.h b/lib/signal.in.h
index fea12e6572d..418d59c582d 100644
--- a/lib/signal.in.h
+++ b/lib/signal.in.h
@@ -55,6 +55,11 @@
 #ifndef _@GUARD_PREFIX@_SIGNAL_H
 #define _@GUARD_PREFIX@_SIGNAL_H
 
+/* This file uses GNULIB_POSIXCHECK, HAVE_RAW_DECL_*.  */
+#if !_GL_CONFIG_H_INCLUDED
+ #error "Please include config.h first."
+#endif
+
 /* For testing the OpenBSD version.  */
 #if (@GNULIB_PTHREAD_SIGMASK@ || defined GNULIB_POSIXCHECK) \
     && defined __OpenBSD__
diff --git a/lib/stat-time.h b/lib/stat-time.h
index 92aa1e64e20..5b2702356ee 100644
--- a/lib/stat-time.h
+++ b/lib/stat-time.h
@@ -20,15 +20,18 @@
 #ifndef STAT_TIME_H
 #define STAT_TIME_H 1
 
+/* This file uses _GL_INLINE_HEADER_BEGIN, _GL_INLINE, _GL_UNUSED,
+   _GL_ATTRIBUTE_PURE, HAVE_STRUCT_STAT_*.  */
+#if !_GL_CONFIG_H_INCLUDED
+ #error "Please include config.h first."
+#endif
+
 #include <errno.h>
 #include <stdckdint.h>
 #include <stddef.h>
 #include <sys/stat.h>
 #include <time.h>
 
-#ifndef _GL_INLINE_HEADER_BEGIN
- #error "Please include config.h first."
-#endif
 _GL_INLINE_HEADER_BEGIN
 #ifndef _GL_STAT_TIME_INLINE
 # define _GL_STAT_TIME_INLINE _GL_INLINE
diff --git a/lib/stddef.in.h b/lib/stddef.in.h
index 6eadcc3d5a4..431e819b8bf 100644
--- a/lib/stddef.in.h
+++ b/lib/stddef.in.h
@@ -18,7 +18,7 @@
 /* Written by Eric Blake.  */
 
 /*
- * POSIX 2008 <stddef.h> for platforms that have issues.
+ * POSIX 2008 and ISO C 23 <stddef.h> for platforms that have issues.
  * <https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/stddef.h.html>
  */
 
@@ -37,9 +37,9 @@
    remember if special invocation has ever been used to obtain wint_t,
    in which case we need to clean up NULL yet again.  */
 
-# if !(defined _@GUARD_PREFIX@_STDDEF_H && defined _GL_STDDEF_WINT_T)
+# if !(defined _@GUARD_PREFIX@_STDDEF_H && defined _@GUARD_PREFIX@_STDDEF_WINT_T)
 #  ifdef __need_wint_t
-#   define _GL_STDDEF_WINT_T
+#   define _@GUARD_PREFIX@_STDDEF_WINT_T
 #  endif
 #  @INCLUDE_NEXT@ @NEXT_STDDEF_H@
    /* On TinyCC, make sure that the macros that indicate the special invocation
@@ -69,6 +69,7 @@ typedef long rpl_max_align_t;
 typedef long max_align_t;
 #     define _MAX_ALIGN_T
 #    endif
+#    define __CLANG_MAX_ALIGN_T_DEFINED
 #    define GNULIB_defined_max_align_t 1
 #   endif
 #  endif
@@ -79,7 +80,7 @@ typedef long max_align_t;
 
 /* On NetBSD 5.0, the definition of NULL lacks proper parentheses.  */
 #  if (@REPLACE_NULL@ \
-       && (!defined _@GUARD_PREFIX@_STDDEF_H || defined _GL_STDDEF_WINT_T))
+       && (!defined _@GUARD_PREFIX@_STDDEF_H || defined _@GUARD_PREFIX@_STDDEF_WINT_T))
 #   undef NULL
 #   ifdef __cplusplus
    /* ISO C++ says that the macro NULL must expand to an integer constant
@@ -100,6 +101,11 @@ typedef long max_align_t;
 #  ifndef _@GUARD_PREFIX@_STDDEF_H
 #   define _@GUARD_PREFIX@_STDDEF_H
 
+/* This file uses _Noreturn.  */
+#if !_GL_CONFIG_H_INCLUDED
+ #error "Please include config.h first."
+#endif
+
 /* Some platforms lack wchar_t.  */
 #if !@HAVE_WCHAR_T@
 # define wchar_t int
@@ -137,11 +143,49 @@ typedef union
   long int __i _GL_STDDEF_ALIGNAS (long int);
 } rpl_max_align_t;
 #   define max_align_t rpl_max_align_t
+#   define __CLANG_MAX_ALIGN_T_DEFINED
 #   define GNULIB_defined_max_align_t 1
 #  endif
 # endif
 #endif
 
+/* ISO C 23 § 7.21.1 The unreachable macro  */
+#ifndef unreachable
+
+/* Code borrowed from verify.h.  */
+# ifndef _GL_HAS_BUILTIN_UNREACHABLE
+#  if defined __clang_major__ && __clang_major__ < 5
+#   define _GL_HAS_BUILTIN_UNREACHABLE 0
+#  elif 4 < __GNUC__ + (5 <= __GNUC_MINOR__)
+#   define _GL_HAS_BUILTIN_UNREACHABLE 1
+#  elif defined __has_builtin
+#   define _GL_HAS_BUILTIN_UNREACHABLE __has_builtin (__builtin_unreachable)
+#  else
+#   define _GL_HAS_BUILTIN_UNREACHABLE 0
+#  endif
+# endif
+
+# if _GL_HAS_BUILTIN_UNREACHABLE
+#  define unreachable() __builtin_unreachable ()
+# elif 1200 <= _MSC_VER
+#  define unreachable() __assume (0)
+# else
+/* Declare abort(), without including <stdlib.h>.  */
+extern
+#  if defined __cplusplus
+"C"
+#  endif
+_Noreturn
+void abort (void)
+#  if defined __cplusplus && (__GLIBC__ >= 2)
+throw ()
+#  endif
+;
+#  define unreachable() abort ()
+# endif
+
+#endif
+
 #  endif /* _@GUARD_PREFIX@_STDDEF_H */
 # endif /* _@GUARD_PREFIX@_STDDEF_H */
 #endif /* __need_XXX */
diff --git a/lib/stdio.in.h b/lib/stdio.in.h
index 098f841738c..6be12c0525d 100644
--- a/lib/stdio.in.h
+++ b/lib/stdio.in.h
@@ -57,6 +57,12 @@
 #ifndef _@GUARD_PREFIX@_STDIO_H
 #define _@GUARD_PREFIX@_STDIO_H
 
+/* This file uses _GL_ATTRIBUTE_DEALLOC, _GL_ATTRIBUTE_FORMAT,
+   _GL_ATTRIBUTE_MALLOC, GNULIB_POSIXCHECK, HAVE_RAW_DECL_*.  */
+#if !_GL_CONFIG_H_INCLUDED
+ #error "Please include config.h first."
+#endif
+
 /* Get va_list.  Needed on many systems, including glibc 2.8.  */
 #include <stdarg.h>
 
@@ -127,6 +133,16 @@
 # endif
 #endif
 
+/* _GL_ATTRIBUTE_MALLOC declares that the function returns a pointer to freshly
+   allocated memory.  */
+#ifndef _GL_ATTRIBUTE_MALLOC
+# if __GNUC__ >= 3 || defined __clang__
+#  define _GL_ATTRIBUTE_MALLOC __attribute__ ((__malloc__))
+# else
+#  define _GL_ATTRIBUTE_MALLOC
+# endif
+#endif
+
 /* An __attribute__ __format__ specifier for a function that takes a format
    string and arguments, where the format string directives are the ones
    standardized by ISO C99 and POSIX.
@@ -204,6 +220,36 @@
 # undef putc_unlocked
 #endif
 
+
+/* Maximum number of characters produced by printing a NaN value.  */
+#ifndef _PRINTF_NAN_LEN_MAX
+# if defined __FreeBSD__ || defined __DragonFly__ \
+     || defined __NetBSD__ \
+     || (defined __APPLE__ && defined __MACH__)
+/* On BSD systems, a NaN value prints as just "nan", without a sign.  */
+#  define _PRINTF_NAN_LEN_MAX 3
+# elif (__GLIBC__ >= 2) || MUSL_LIBC || defined __OpenBSD__ || defined __sun || defined __CYGWIN__
+/* glibc, musl libc, OpenBSD, Solaris libc, and Cygwin produce "[-]nan".  */
+#  define _PRINTF_NAN_LEN_MAX 4
+# elif defined _AIX
+/* AIX produces "[-]NaNQ".  */
+#  define _PRINTF_NAN_LEN_MAX 5
+# elif defined _WIN32 && !defined __CYGWIN__
+/* On native Windows, the output can be:
+   - with MSVC ucrt: "[-]nan" or "[-]nan(ind)" or "[-]nan(snan)",
+   - with mingw: "[-]1.#IND" or "[-]1.#QNAN".  */
+#  define _PRINTF_NAN_LEN_MAX 10
+# elif defined __sgi
+/* On IRIX, the output typically is "[-]nan0xNNNNNNNN" with 8 hexadecimal
+   digits.  */
+#  define _PRINTF_NAN_LEN_MAX 14
+# else
+/* We don't know, but 32 should be a safe maximum.  */
+#  define _PRINTF_NAN_LEN_MAX 32
+# endif
+#endif
+
+
 #if @GNULIB_DPRINTF@
 # if @REPLACE_DPRINTF@
 #  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
@@ -286,7 +332,8 @@ _GL_CXXALIASWARN (fcloseall);
 #  endif
 _GL_FUNCDECL_RPL (fdopen, FILE *,
                   (int fd, const char *mode)
-                  _GL_ARG_NONNULL ((2)) _GL_ATTRIBUTE_DEALLOC (fclose, 1));
+                  _GL_ARG_NONNULL ((2)) _GL_ATTRIBUTE_DEALLOC (fclose, 1)
+                  _GL_ATTRIBUTE_MALLOC);
 _GL_CXXALIAS_RPL (fdopen, FILE *, (int fd, const char *mode));
 # elif defined _WIN32 && !defined __CYGWIN__
 #  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
@@ -299,7 +346,8 @@ _GL_CXXALIAS_MDA (fdopen, FILE *, (int fd, const char *mode));
 /* For -Wmismatched-dealloc: Associate fdopen with fclose or rpl_fclose.  */
 _GL_FUNCDECL_SYS (fdopen, FILE *,
                   (int fd, const char *mode)
-                  _GL_ARG_NONNULL ((2)) _GL_ATTRIBUTE_DEALLOC (fclose, 1));
+                  _GL_ARG_NONNULL ((2)) _GL_ATTRIBUTE_DEALLOC (fclose, 1)
+                  _GL_ATTRIBUTE_MALLOC);
 #  endif
 _GL_CXXALIAS_SYS (fdopen, FILE *, (int fd, const char *mode));
 # endif
@@ -309,7 +357,8 @@ _GL_CXXALIASWARN (fdopen);
 /* For -Wmismatched-dealloc: Associate fdopen with fclose or rpl_fclose.  */
 _GL_FUNCDECL_SYS (fdopen, FILE *,
                   (int fd, const char *mode)
-                  _GL_ARG_NONNULL ((2)) _GL_ATTRIBUTE_DEALLOC (fclose, 1));
+                  _GL_ARG_NONNULL ((2)) _GL_ATTRIBUTE_DEALLOC (fclose, 1)
+                  _GL_ATTRIBUTE_MALLOC);
 # endif
 # if defined GNULIB_POSIXCHECK
 #  undef fdopen
@@ -420,7 +469,8 @@ _GL_CXXALIASWARN (fileno);
 #  endif
 _GL_FUNCDECL_RPL (fopen, FILE *,
                   (const char *restrict filename, const char *restrict mode)
-                  _GL_ARG_NONNULL ((1, 2)) _GL_ATTRIBUTE_DEALLOC (fclose, 1));
+                  _GL_ARG_NONNULL ((1, 2)) _GL_ATTRIBUTE_DEALLOC (fclose, 1)
+                  _GL_ATTRIBUTE_MALLOC);
 _GL_CXXALIAS_RPL (fopen, FILE *,
                   (const char *restrict filename, const char *restrict mode));
 # else
@@ -967,6 +1017,10 @@ _GL_WARN_ON_USE (gets, "gets is a security hole - use fgets instead");
 _GL_CXXALIAS_MDA (getw, int, (FILE *restrict stream));
 # else
 #  if @HAVE_DECL_GETW@
+#   if defined __APPLE__ && defined __MACH__
+/* The presence of the declaration depends on _POSIX_C_SOURCE.  */
+_GL_FUNCDECL_SYS (getw, int, (FILE *restrict stream));
+#   endif
 _GL_CXXALIAS_SYS (getw, int, (FILE *restrict stream));
 #  endif
 # endif
@@ -1071,13 +1125,15 @@ _GL_WARN_ON_USE (perror, "perror is not always POSIX compliant - "
 #  endif
 _GL_FUNCDECL_RPL (popen, FILE *,
                   (const char *cmd, const char *mode)
-                  _GL_ARG_NONNULL ((1, 2)) _GL_ATTRIBUTE_DEALLOC (pclose, 1));
+                  _GL_ARG_NONNULL ((1, 2)) _GL_ATTRIBUTE_DEALLOC (pclose, 1)
+                  _GL_ATTRIBUTE_MALLOC);
 _GL_CXXALIAS_RPL (popen, FILE *, (const char *cmd, const char *mode));
 # else
 #  if !@HAVE_POPEN@ || __GNUC__ >= 11
 _GL_FUNCDECL_SYS (popen, FILE *,
                   (const char *cmd, const char *mode)
-                  _GL_ARG_NONNULL ((1, 2)) _GL_ATTRIBUTE_DEALLOC (pclose, 1));
+                  _GL_ARG_NONNULL ((1, 2)) _GL_ATTRIBUTE_DEALLOC (pclose, 1)
+                  _GL_ATTRIBUTE_MALLOC);
 #  endif
 _GL_CXXALIAS_SYS (popen, FILE *, (const char *cmd, const char *mode));
 # endif
@@ -1087,7 +1143,8 @@ _GL_CXXALIASWARN (popen);
 /* For -Wmismatched-dealloc: Associate popen with pclose or rpl_pclose.  */
 _GL_FUNCDECL_SYS (popen, FILE *,
                   (const char *cmd, const char *mode)
-                  _GL_ARG_NONNULL ((1, 2)) _GL_ATTRIBUTE_DEALLOC (pclose, 1));
+                  _GL_ARG_NONNULL ((1, 2)) _GL_ATTRIBUTE_DEALLOC (pclose, 1)
+                  _GL_ATTRIBUTE_MALLOC);
 # endif
 # if defined GNULIB_POSIXCHECK
 #  undef popen
@@ -1210,6 +1267,10 @@ _GL_CXXALIASWARN (puts);
 _GL_CXXALIAS_MDA (putw, int, (int w, FILE *restrict stream));
 # else
 #  if @HAVE_DECL_PUTW@
+#   if defined __APPLE__ && defined __MACH__
+/* The presence of the declaration depends on _POSIX_C_SOURCE.  */
+_GL_FUNCDECL_SYS (putw, int, (int w, FILE *restrict stream));
+#   endif
 _GL_CXXALIAS_SYS (putw, int, (int w, FILE *restrict stream));
 #  endif
 # endif
@@ -1421,13 +1482,15 @@ _GL_CXXALIASWARN (tempnam);
 #   define tmpfile rpl_tmpfile
 #  endif
 _GL_FUNCDECL_RPL (tmpfile, FILE *, (void)
-                                   _GL_ATTRIBUTE_DEALLOC (fclose, 1));
+                                   _GL_ATTRIBUTE_DEALLOC (fclose, 1)
+                                   _GL_ATTRIBUTE_MALLOC);
 _GL_CXXALIAS_RPL (tmpfile, FILE *, (void));
 # else
 #  if __GNUC__ >= 11
 /* For -Wmismatched-dealloc: Associate tmpfile with fclose or rpl_fclose.  */
 _GL_FUNCDECL_SYS (tmpfile, FILE *, (void)
-                                   _GL_ATTRIBUTE_DEALLOC (fclose, 1));
+                                   _GL_ATTRIBUTE_DEALLOC (fclose, 1)
+                                   _GL_ATTRIBUTE_MALLOC);
 #  endif
 _GL_CXXALIAS_SYS (tmpfile, FILE *, (void));
 # endif
@@ -1438,7 +1501,8 @@ _GL_CXXALIASWARN (tmpfile);
 # if @GNULIB_FCLOSE@ && __GNUC__ >= 11 && !defined tmpfile
 /* For -Wmismatched-dealloc: Associate tmpfile with fclose or rpl_fclose.  */
 _GL_FUNCDECL_SYS (tmpfile, FILE *, (void)
-                                   _GL_ATTRIBUTE_DEALLOC (fclose, 1));
+                                   _GL_ATTRIBUTE_DEALLOC (fclose, 1)
+                                   _GL_ATTRIBUTE_MALLOC);
 # endif
 # if defined GNULIB_POSIXCHECK
 #  undef tmpfile
diff --git a/lib/stdlib.in.h b/lib/stdlib.in.h
index a91f4e23d67..1479a2b2871 100644
--- a/lib/stdlib.in.h
+++ b/lib/stdlib.in.h
@@ -37,6 +37,12 @@
 #ifndef _@GUARD_PREFIX@_STDLIB_H
 #define _@GUARD_PREFIX@_STDLIB_H
 
+/* This file uses _Noreturn, _GL_ATTRIBUTE_DEALLOC, _GL_ATTRIBUTE_MALLOC,
+   _GL_ATTRIBUTE_PURE, GNULIB_POSIXCHECK, HAVE_RAW_DECL_*.  */
+#if !_GL_CONFIG_H_INCLUDED
+ #error "Please include config.h first."
+#endif
+
 /* NetBSD 5.0 mis-defines NULL.  */
 #include <stddef.h>
 
@@ -67,9 +73,7 @@
 #  include <random.h>
 # endif
 
-# if !@HAVE_STRUCT_RANDOM_DATA@ || @REPLACE_RANDOM_R@ || !@HAVE_RANDOM_R@
-#  include <stdint.h>
-# endif
+# include <stdint.h>
 
 # if !@HAVE_STRUCT_RANDOM_DATA@
 /* Define 'struct random_data'.
@@ -461,7 +465,7 @@ _GL_WARN_ON_USE (getloadavg, "getloadavg is not portable - "
 #   undef getprogname
 #   define getprogname rpl_getprogname
 #  endif
-#  ifdef HAVE_DECL_PROGRAM_INVOCATION_NAME
+#  if @HAVE_DECL_PROGRAM_INVOCATION_NAME@
 _GL_FUNCDECL_RPL (getprogname, const char *, (void) _GL_ATTRIBUTE_PURE);
 #  else
 _GL_FUNCDECL_RPL (getprogname, const char *, (void));
@@ -469,7 +473,7 @@ _GL_FUNCDECL_RPL (getprogname, const char *, (void));
 _GL_CXXALIAS_RPL (getprogname, const char *, (void));
 # else
 #  if !@HAVE_GETPROGNAME@
-#   ifdef HAVE_DECL_PROGRAM_INVOCATION_NAME
+#   if @HAVE_DECL_PROGRAM_INVOCATION_NAME@
 _GL_FUNCDECL_SYS (getprogname, const char *, (void) _GL_ATTRIBUTE_PURE);
 #   else
 _GL_FUNCDECL_SYS (getprogname, const char *, (void));
@@ -589,6 +593,51 @@ _GL_WARN_ON_USE (malloc, "malloc is not POSIX compliant everywhere - "
 # endif
 #endif
 
+/* Return maximum number of bytes of a multibyte character.  */
+#if @REPLACE_MB_CUR_MAX@
+# if !GNULIB_defined_MB_CUR_MAX
+static inline
+int gl_MB_CUR_MAX (void)
+{
+  /* Turn the value 3 to the value 4, as needed for the UTF-8 encoding.  */
+  return MB_CUR_MAX + (MB_CUR_MAX == 3);
+}
+#  undef MB_CUR_MAX
+#  define MB_CUR_MAX gl_MB_CUR_MAX ()
+#  define GNULIB_defined_MB_CUR_MAX 1
+# endif
+#endif
+
+/* Convert a string to a wide string.  */
+#if @GNULIB_MBSTOWCS@
+# if @REPLACE_MBSTOWCS@
+#  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
+#   undef mbstowcs
+#   define mbstowcs rpl_mbstowcs
+#  endif
+_GL_FUNCDECL_RPL (mbstowcs, size_t,
+                  (wchar_t *restrict dest, const char *restrict src,
+                   size_t len)
+                  _GL_ARG_NONNULL ((2)));
+_GL_CXXALIAS_RPL (mbstowcs, size_t,
+                  (wchar_t *restrict dest, const char *restrict src,
+                   size_t len));
+# else
+_GL_CXXALIAS_SYS (mbstowcs, size_t,
+                  (wchar_t *restrict dest, const char *restrict src,
+                   size_t len));
+# endif
+# if __GLIBC__ >= 2
+_GL_CXXALIASWARN (mbstowcs);
+# endif
+#elif defined GNULIB_POSIXCHECK
+# undef mbstowcs
+# if HAVE_RAW_DECL_MBSTOWCS
+_GL_WARN_ON_USE (mbstowcs, "mbstowcs is unportable - "
+                 "use gnulib module mbstowcs for portability");
+# endif
+#endif
+
 /* Convert a multibyte character to a wide character.  */
 #if @GNULIB_MBTOWC@
 # if @REPLACE_MBTOWC@
@@ -1009,7 +1058,9 @@ _GL_FUNCDECL_SYS (random, long, (void));
                                int.  */
 _GL_CXXALIAS_SYS_CAST (random, long, (void));
 # endif
+# if __GLIBC__ >= 2
 _GL_CXXALIASWARN (random);
+# endif
 #elif defined GNULIB_POSIXCHECK
 # undef random
 # if HAVE_RAW_DECL_RANDOM
@@ -1034,7 +1085,9 @@ _GL_FUNCDECL_SYS (srandom, void, (unsigned int seed));
                                        unsigned long seed.  */
 _GL_CXXALIAS_SYS_CAST (srandom, void, (unsigned int seed));
 # endif
+# if __GLIBC__ >= 2
 _GL_CXXALIASWARN (srandom);
+# endif
 #elif defined GNULIB_POSIXCHECK
 # undef srandom
 # if HAVE_RAW_DECL_SRANDOM
diff --git a/lib/string.in.h b/lib/string.in.h
index b6bf432e1f1..912d0f7a306 100644
--- a/lib/string.in.h
+++ b/lib/string.in.h
@@ -44,6 +44,12 @@
 #ifndef _@GUARD_PREFIX@_STRING_H
 #define _@GUARD_PREFIX@_STRING_H
 
+/* This file uses _GL_ATTRIBUTE_DEALLOC, _GL_ATTRIBUTE_MALLOC,
+   _GL_ATTRIBUTE_PURE, GNULIB_POSIXCHECK, HAVE_RAW_DECL_*.  */
+#if !_GL_CONFIG_H_INCLUDED
+ #error "Please include config.h first."
+#endif
+
 /* NetBSD 5.0 mis-defines NULL.  */
 #include <stddef.h>
 
diff --git a/lib/strtol.c b/lib/strtol.c
index d11269b2622..b93483dca49 100644
--- a/lib/strtol.c
+++ b/lib/strtol.c
@@ -288,6 +288,11 @@ INTERNAL (strtol) (const STRING_TYPE *nptr, STRING_TYPE **endptr,
           s += 2;
           base = 16;
         }
+      else if ((base == 0 || base == 2) && TOUPPER (s[1]) == L_('B'))
+        {
+          s += 2;
+          base = 2;
+        }
       else if (base == 0)
         base = 8;
     }
@@ -378,11 +383,14 @@ INTERNAL (strtol) (const STRING_TYPE *nptr, STRING_TYPE **endptr,
 noconv:
   /* We must handle a special case here: the base is 0 or 16 and the
      first two characters are '0' and 'x', but the rest are no
-     hexadecimal digits.  This is no error case.  We return 0 and
-     ENDPTR points to the 'x'.  */
+     hexadecimal digits.  Likewise when the base is 0 or 2 and the
+     first two characters are '0' and 'b', but the rest are no binary
+     digits.  This is no error case.  We return 0 and ENDPTR points to
+     the 'x' or 'b'.  */
   if (endptr != NULL)
     {
-      if (save - nptr >= 2 && TOUPPER (save[-1]) == L_('X')
+      if (save - nptr >= 2
+          && (TOUPPER (save[-1]) == L_('X') || TOUPPER (save[-1]) == L_('B'))
           && save[-2] == L_('0'))
         *endptr = (STRING_TYPE *) &save[-1];
       else
diff --git a/lib/sys_random.in.h b/lib/sys_random.in.h
index 8dca1326837..b240033bcbf 100644
--- a/lib/sys_random.in.h
+++ b/lib/sys_random.in.h
@@ -45,6 +45,11 @@
 #ifndef _@GUARD_PREFIX@_SYS_RANDOM_H
 #define _@GUARD_PREFIX@_SYS_RANDOM_H
 
+/* This file uses GNULIB_POSIXCHECK, HAVE_RAW_DECL_*.  */
+#if !_GL_CONFIG_H_INCLUDED
+ #error "Please include config.h first."
+#endif
+
 #include <sys/types.h>
 
 /* Define the GRND_* constants.  */
diff --git a/lib/sys_select.in.h b/lib/sys_select.in.h
index 13440fa6f0a..3abfc48af09 100644
--- a/lib/sys_select.in.h
+++ b/lib/sys_select.in.h
@@ -19,6 +19,13 @@
 # endif
 @PRAGMA_COLUMNS@
 
+/* This file uses #include_next of a system file that defines time_t.
+   For the 'year2038' module to work right, <config.h> needs to have been
+   included before.  */
+#if !_GL_CONFIG_H_INCLUDED
+ #error "Please include config.h first."
+#endif
+
 /* On OSF/1 and Solaris 2.6, <sys/types.h> and <sys/time.h>
    both include <sys/select.h>.
    On Cygwin and OpenBSD, <sys/time.h> includes <sys/select.h>.
@@ -71,6 +78,11 @@
 
 #ifndef _@GUARD_PREFIX@_SYS_SELECT_H
 
+/* This file uses GNULIB_POSIXCHECK, HAVE_RAW_DECL_*.  */
+#if !_GL_CONFIG_H_INCLUDED
+ #error "Please include config.h first."
+#endif
+
 /* On many platforms, <sys/select.h> assumes prior inclusion of
    <sys/types.h>.  Also, mingw defines sigset_t there, instead of
    in <signal.h> where it belongs.  */
diff --git a/lib/sys_stat.in.h b/lib/sys_stat.in.h
index 0c2f39c12bf..ad4da17fa46 100644
--- a/lib/sys_stat.in.h
+++ b/lib/sys_stat.in.h
@@ -25,6 +25,13 @@
 #endif
 @PRAGMA_COLUMNS@
 
+/* This file uses #include_next of a system file that defines time_t.
+   For the 'year2038' module to work right, <config.h> needs to have been
+   included before.  */
+#if !_GL_CONFIG_H_INCLUDED
+ #error "Please include config.h first."
+#endif
+
 #if defined __need_system_sys_stat_h
 /* Special invocation convention.  */
 
@@ -48,6 +55,11 @@
 #ifndef _@GUARD_PREFIX@_SYS_STAT_H
 #define _@GUARD_PREFIX@_SYS_STAT_H
 
+/* This file uses GNULIB_POSIXCHECK, HAVE_RAW_DECL_*.  */
+#if !_GL_CONFIG_H_INCLUDED
+ #error "Please include config.h first."
+#endif
+
 /* The definitions of _GL_FUNCDECL_RPL etc. are copied here.  */
 
 /* The definition of _GL_ARG_NONNULL is copied here.  */
diff --git a/lib/sys_time.in.h b/lib/sys_time.in.h
index e833d551677..59cce1440da 100644
--- a/lib/sys_time.in.h
+++ b/lib/sys_time.in.h
@@ -24,6 +24,13 @@
 #endif
 @PRAGMA_COLUMNS@
 
+/* This file uses #include_next of a system file that defines time_t.
+   For the 'year2038' module to work right, <config.h> needs to have been
+   included before.  */
+#if !_GL_CONFIG_H_INCLUDED
+ #error "Please include config.h first."
+#endif
+
 /* On Cygwin and on many BSDish systems, <sys/time.h> includes itself
    recursively via <sys/select.h>.
    Simply delegate to the system's header in this case; it is a no-op.
@@ -41,6 +48,11 @@
 #ifndef _@GUARD_PREFIX@_SYS_TIME_H
 #define _@GUARD_PREFIX@_SYS_TIME_H
 
+/* This file uses GNULIB_POSIXCHECK, HAVE_RAW_DECL_*.  */
+#if !_GL_CONFIG_H_INCLUDED
+ #error "Please include config.h first."
+#endif
+
 #if ! @HAVE_SYS_TIME_H@
 # include <time.h>
 #endif
diff --git a/lib/sys_types.in.h b/lib/sys_types.in.h
index 082a6c674de..ea77e140be9 100644
--- a/lib/sys_types.in.h
+++ b/lib/sys_types.in.h
@@ -20,6 +20,13 @@
 #endif
 @PRAGMA_COLUMNS@
 
+/* This file uses #include_next of a system file that defines time_t.
+   For the 'year2038' module to work right, <config.h> needs to have been
+   included before.  */
+#if !_GL_CONFIG_H_INCLUDED
+ #error "Please include config.h first."
+#endif
+
 #if defined _WIN32 && !defined __CYGWIN__ \
     && (defined __need_off_t || defined __need___off64_t \
         || defined __need_ssize_t || defined __need_time_t)
diff --git a/lib/time.in.h b/lib/time.in.h
index 3f9af920e34..06428adb1d0 100644
--- a/lib/time.in.h
+++ b/lib/time.in.h
@@ -20,6 +20,13 @@
 #endif
 @PRAGMA_COLUMNS@
 
+/* This file uses #include_next of a system file that defines time_t.
+   For the 'year2038' module to work right, <config.h> needs to have been
+   included before.  */
+#if !_GL_CONFIG_H_INCLUDED
+ #error "Please include config.h first."
+#endif
+
 /* Don't get in the way of glibc when it includes time.h merely to
    declare a few standard symbols, rather than to declare all the
    symbols.  (However, skip this for MinGW as it treats __need_time_t
@@ -45,6 +52,12 @@
 
 # @INCLUDE_NEXT@ @NEXT_TIME_H@
 
+/* This file uses _GL_ATTRIBUTE_DEPRECATED, GNULIB_POSIXCHECK,
+   HAVE_RAW_DECL_*.  */
+# if !_GL_CONFIG_H_INCLUDED
+#  error "Please include config.h first."
+# endif
+
 /* NetBSD 5.0 mis-defines NULL.  */
 # include <stddef.h>
 
@@ -154,7 +167,9 @@ _GL_CXXALIAS_RPL (time, time_t, (time_t *__tp));
 #  else
 _GL_CXXALIAS_SYS (time, time_t, (time_t *__tp));
 #  endif
+#  if __GLIBC__ >= 2
 _GL_CXXALIASWARN (time);
+#  endif
 # endif
 
 /* Sleep for at least RQTP seconds unless interrupted,  If interrupted,
@@ -341,7 +356,9 @@ _GL_CXXALIASWARN (strptime);
 #   if !(defined __cplusplus && defined GNULIB_NAMESPACE)
 #    define ctime rpl_ctime
 #   endif
+#   ifndef __cplusplus
 _GL_ATTRIBUTE_DEPRECATED
+#   endif
 _GL_FUNCDECL_RPL (ctime, char *, (time_t const *__tp)
                                  _GL_ARG_NONNULL ((1)));
 _GL_CXXALIAS_RPL (ctime, char *, (time_t const *__tp));
diff --git a/lib/timespec.h b/lib/timespec.h
index ba78647f09a..0bdfd76ef78 100644
--- a/lib/timespec.h
+++ b/lib/timespec.h
@@ -19,11 +19,14 @@
 #if ! defined TIMESPEC_H
 #define TIMESPEC_H
 
-#include <time.h>
-
-#ifndef _GL_INLINE_HEADER_BEGIN
+/* This file uses _GL_INLINE_HEADER_BEGIN, _GL_INLINE, _GL_ATTRIBUTE_CONST,
+   _GL_ATTRIBUTE_PURE, _GL_CMP.  */
+#if !_GL_CONFIG_H_INCLUDED
  #error "Please include config.h first."
 #endif
+
+#include <time.h>
+
 _GL_INLINE_HEADER_BEGIN
 #ifndef _GL_TIMESPEC_INLINE
 # define _GL_TIMESPEC_INLINE _GL_INLINE
diff --git a/lib/u64.h b/lib/u64.h
index 0353ad4d9af..8a99335b6aa 100644
--- a/lib/u64.h
+++ b/lib/u64.h
@@ -17,11 +17,13 @@
 
 /* Written by Paul Eggert.  */
 
-#include <stdint.h>
-
-#ifndef _GL_INLINE_HEADER_BEGIN
+/* This file uses _GL_INLINE_HEADER_BEGIN, _GL_INLINE.  */
+#if !_GL_CONFIG_H_INCLUDED
  #error "Please include config.h first."
 #endif
+
+#include <stdint.h>
+
 _GL_INLINE_HEADER_BEGIN
 #ifndef _GL_U64_INLINE
 # define _GL_U64_INLINE _GL_INLINE
diff --git a/lib/unistd.in.h b/lib/unistd.in.h
index 8ba9867894e..2ae040a76b3 100644
--- a/lib/unistd.in.h
+++ b/lib/unistd.in.h
@@ -69,6 +69,12 @@
 #if !defined _@GUARD_PREFIX@_UNISTD_H && !defined _GL_INCLUDING_WINSOCK2_H
 #define _@GUARD_PREFIX@_UNISTD_H
 
+/* This file uses _GL_INLINE_HEADER_BEGIN, _GL_INLINE, GNULIB_POSIXCHECK,
+   HAVE_RAW_DECL_*.  */
+#if !_GL_CONFIG_H_INCLUDED
+ #error "Please include config.h first."
+#endif
+
 /* NetBSD 5.0 mis-defines NULL.  Also get size_t.  */
 /* But avoid namespace pollution on glibc systems.  */
 #ifndef __GLIBC__
@@ -170,9 +176,6 @@
 # include <getopt-pfx-core.h>
 #endif
 
-#ifndef _GL_INLINE_HEADER_BEGIN
- #error "Please include config.h first."
-#endif
 _GL_INLINE_HEADER_BEGIN
 #ifndef _GL_UNISTD_INLINE
 # define _GL_UNISTD_INLINE _GL_INLINE
diff --git a/lib/unlocked-io.h b/lib/unlocked-io.h
index fdef624ab9c..4830df4a747 100644
--- a/lib/unlocked-io.h
+++ b/lib/unlocked-io.h
@@ -31,6 +31,11 @@
    the *_unlocked functions directly.  On hosts that lack those
    functions, invoke the non-thread-safe versions instead.  */
 
+/* This file uses HAVE_DECL_*_UNLOCKED.  */
+# if !_GL_CONFIG_H_INCLUDED
+#  error "Please include config.h first."
+# endif
+
 # include <stdio.h>
 
 # if HAVE_DECL_CLEARERR_UNLOCKED || defined clearerr_unlocked
diff --git a/lib/utimens.h b/lib/utimens.h
index a7056981f32..4a21792a7e4 100644
--- a/lib/utimens.h
+++ b/lib/utimens.h
@@ -17,6 +17,11 @@
 
 /* Written by Paul Eggert.  */
 
+/* This file uses _GL_INLINE_HEADER_BEGIN, _GL_INLINE.  */
+#if !_GL_CONFIG_H_INCLUDED
+ #error "Please include config.h first."
+#endif
+
 #include <time.h>
 int fdutimens (int, char const *, struct timespec const [2]);
 int utimens (char const *, struct timespec const [2]);
@@ -26,9 +31,6 @@ int lutimens (char const *, struct timespec const [2]);
 # include <fcntl.h>
 # include <sys/stat.h>
 
-#ifndef _GL_INLINE_HEADER_BEGIN
- #error "Please include config.h first."
-#endif
 _GL_INLINE_HEADER_BEGIN
 #ifndef _GL_UTIMENS_INLINE
 # define _GL_UTIMENS_INLINE _GL_INLINE
diff --git a/lib/verify.h b/lib/verify.h
index f0b3fc5851b..e4af91517e6 100644
--- a/lib/verify.h
+++ b/lib/verify.h
@@ -241,10 +241,16 @@ template <int w>
 #   define _Static_assert(...) \
       _GL_VERIFY (__VA_ARGS__, "static assertion failed", -)
 #  else
-    /* Work around MSVC preprocessor incompatibility with ISO C; see
-       <https://stackoverflow.com/questions/5134523/>.  */
-#   define _Static_assert(R, ...) \
-      _GL_VERIFY ((R), "static assertion failed", -)
+#   if defined __cplusplus && _MSC_VER >= 1910
+     /* In MSVC 14.1 or newer, static_assert accepts one or two arguments,
+        but _Static_assert is not defined.  */
+#    define _Static_assert static_assert
+#   else
+     /* Work around MSVC preprocessor incompatibility with ISO C; see
+        <https://stackoverflow.com/questions/5134523/>.  */
+#    define _Static_assert(R, ...) \
+       _GL_VERIFY ((R), "static assertion failed", -)
+#   endif
 #  endif
 # endif
 /* Define static_assert if needed.  */
@@ -252,7 +258,7 @@ template <int w>
       && __STDC_VERSION__ < 202311 \
       && (!defined __cplusplus \
           || (__cpp_static_assert < 201411 \
-              && __GNUG__ < 6 && __clang_major__ < 6)))
+              && __GNUG__ < 6 && __clang_major__ < 6 && _MSC_VER < 1910)))
 #  if defined __cplusplus && _MSC_VER >= 1900 && !defined __clang__
 /* MSVC 14 in C++ mode supports the two-arguments static_assert but not
    the one-argument static_assert, and it does not support _Static_assert.
@@ -285,14 +291,16 @@ template <int w>
 # define _GL_HAS_BUILTIN_TRAP 0
 #endif
 
-#if defined __clang_major__ && __clang_major__ < 5
-# define _GL_HAS_BUILTIN_UNREACHABLE 0
-#elif 4 < __GNUC__ + (5 <= __GNUC_MINOR__)
-# define _GL_HAS_BUILTIN_UNREACHABLE 1
-#elif defined __has_builtin
-# define _GL_HAS_BUILTIN_UNREACHABLE __has_builtin (__builtin_unreachable)
-#else
-# define _GL_HAS_BUILTIN_UNREACHABLE 0
+#ifndef _GL_HAS_BUILTIN_UNREACHABLE
+# if defined __clang_major__ && __clang_major__ < 5
+#  define _GL_HAS_BUILTIN_UNREACHABLE 0
+# elif 4 < __GNUC__ + (5 <= __GNUC_MINOR__)
+#  define _GL_HAS_BUILTIN_UNREACHABLE 1
+# elif defined __has_builtin
+#  define _GL_HAS_BUILTIN_UNREACHABLE __has_builtin (__builtin_unreachable)
+# else
+#  define _GL_HAS_BUILTIN_UNREACHABLE 0
+# endif
 #endif
 
 /* Each of these macros verifies that its argument R is nonzero.  To