[PATCH] samples/vfs: Undefine conflicting AT_RENAME_* macros in test-statx

[Madhur Kumar <madhurkumar004@gmail.com>]

The test-statx program in samples/vfs/ includes both <stdio.h> and
usr/include/linux/fcntl.h, leading to redefinition errors for
AT_RENAME_NOREPLACE, AT_RENAME_EXCHANGE, and AT_RENAME_WHITEOUT. These
macros, defined in both glibc headers (via <stdio.h>, likely including
<fcntl.h>) and the kernel's usr/include/linux/fcntl.h, are not directly
used in test-statx.c but cause a build failure with -Werror due to
redefinition warnings like:

    In file included from samples/vfs/test-statx.c:23:
    usr/include/linux/fcntl.h:160:9: error: ‘AT_RENAME_NOREPLACE’ redefined [-Werror]
    160 | #define AT_RENAME_NOREPLACE     0x0001
        |         ^~~~~~~~~~~~~~~~~~~
    In file included from samples/vfs/test-statx.c:13:
    /usr/include/stdio.h:171:10: note: this is the location of the previous definition
    171 | # define AT_RENAME_NOREPLACE RENAME_NOREPLACE
        |          ^~~~~~~~~~~~~~~~~~~
    usr/include/linux/fcntl.h:161:9: error: ‘AT_RENAME_EXCHANGE’ redefined [-Werror]
    161 | #define AT_RENAME_EXCHANGE      0x0002
        |         ^~~~~~~~~~~~~~~~~~
    /usr/include/stdio.h:173:10: note: this is the location of the previous definition
    173 | # define AT_RENAME_EXCHANGE RENAME_EXCHANGE
        |          ^~~~~~~~~~~~~~~~~~
    usr/include/linux/fcntl.h:162:9: error: ‘AT_RENAME_WHITEOUT’ redefined [-Werror]
    162 | #define AT_RENAME_WHITEOUT      0x0004
        |         ^~~~~~~~~~~~~~~~~~
    /usr/include/stdio.h:175:10: note: this is the location of the previous definition
    175 | # define AT_RENAME_WHITEOUT RENAME_WHITEOUT
        |          ^~~~~~~~~~~~~~~~~~

Since test-statx relies on other kernel-specific definitions from
usr/include/linux/fcntl.h, this patch adds #undef directives for the
conflicting macros before including the kernel header, ensuring the
kernel's definitions are used without warnings.

Signed-off-by: Madhur Kumar <madhurkumar004@gmail.com>
---
 samples/vfs/test-statx.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/samples/vfs/test-statx.c b/samples/vfs/test-statx.c
index 49c7a46cee07..17332100a2b5 100644
--- a/samples/vfs/test-statx.c
+++ b/samples/vfs/test-statx.c
@@ -20,6 +20,9 @@
 #include <sys/syscall.h>
 #include <sys/types.h>
 #include <linux/stat.h>
+#undef AT_RENAME_NOREPLACE
+#undef AT_RENAME_EXCHANGE
+#undef AT_RENAME_WHITEOUT
 #include <linux/fcntl.h>
 #define statx foo
 #define statx_timestamp foo_timestamp
-- 
2.51.0