[PATCH v3] uapi/linux/fcntl: remove AT_RENAME* macros

[Randy Dunlap <rdunlap@infradead.org>]

Don't define the AT_RENAME_* macros at all since the kernel does not
use them nor does the kernel need to provide them for userspace.
Leave them as comments in <uapi/linux/fcntl.h> only as an example.

The AT_RENAME_* macros have recently been added to glibc's <stdio.h>.
For a kernel allmodconfig build, this made the macros be defined
differently in 2 places (same values but different macro text),
causing build errors/warnings (duplicate definitions) in both
samples/watch_queue/watch_test.c and samples/vfs/test-statx.c.
(<linux/fcntl.h> is included indirecty in both programs above.)

Fixes: b4fef22c2fb9 ("uapi: explain how per-syscall AT_* flags should be allocated")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
---
Cc: Amir Goldstein <amir73il@gmail.com>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: Alexander Aring <alex.aring@gmail.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Aleksa Sarai <cyphar@cyphar.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: David Howells <dhowells@redhat.com>
CC: linux-api@vger.kernel.org
To: linux-fsdevel@vger.kernel.org
---
 include/uapi/linux/fcntl.h |    6 ++++++
 1 file changed, 6 insertions(+)

--- linux-next-20250819.orig/include/uapi/linux/fcntl.h
+++ linux-next-20250819/include/uapi/linux/fcntl.h
@@ -155,10 +155,16 @@
  * as possible, so we can use them for generic bits in the future if necessary.
  */
 
+/*
+ * Note: This is an example of how the AT_RENAME_* flags could be defined,
+ * but the kernel has no need to define them, so leave them as comments.
+ */
 /* Flags for renameat2(2) (must match legacy RENAME_* flags). */
+/*
 #define AT_RENAME_NOREPLACE	0x0001
 #define AT_RENAME_EXCHANGE	0x0002
 #define AT_RENAME_WHITEOUT	0x0004
+*/
 
 /* Flag for faccessat(2). */
 #define AT_EACCESS		0x200	/* Test access permitted for