Add AT_* constants from Linux 6.12

[Joseph Myers]

Linux 6.12 adds AT_RENAME_* aliases for RENAME_* flags for renameat2,
and also AT_HANDLE_MNT_ID_UNIQUE.  Add the first set of aliases to
stdio.h alongside the RENAME_* names, and AT_HANDLE_MNT_ID_UNIQUE to
bits/fcntl-linux.h.

Tested for x86_64.

diff --git a/libio/stdio.h b/libio/stdio.h
index 4436525731..d042b36618 100644
--- a/libio/stdio.h
+++ b/libio/stdio.h
@@ -168,8 +168,11 @@ extern int renameat (int __oldfd, const char *__old, int __newfd,
 #ifdef __USE_GNU
 /* Flags for renameat2.  */
 # define RENAME_NOREPLACE (1 << 0)
+# define AT_RENAME_NOREPLACE RENAME_NOREPLACE
 # define RENAME_EXCHANGE (1 << 1)
+# define AT_RENAME_EXCHANGE RENAME_EXCHANGE
 # define RENAME_WHITEOUT (1 << 2)
+# define AT_RENAME_WHITEOUT RENAME_WHITEOUT
 
 /* Rename file OLD relative to OLDFD to NEW relative to NEWFD, with
    additional flags.  */
diff --git a/sysdeps/unix/sysv/linux/bits/fcntl-linux.h b/sysdeps/unix/sysv/linux/bits/fcntl-linux.h
index dfc554aafc..f425a4bf22 100644
--- a/sysdeps/unix/sysv/linux/bits/fcntl-linux.h
+++ b/sysdeps/unix/sysv/linux/bits/fcntl-linux.h
@@ -379,6 +379,8 @@ struct file_handle
 						identity and may not
 						be usable to
 						open_by_handle_at.  */
+# define AT_HANDLE_MNT_ID_UNIQUE 1 /* Return the 64-bit unique mount
+				      ID.  */
 #endif
 
 __BEGIN_DECLS

-- 
Joseph S. Myers
josmyers@redhat.com