[glibc] Add FD_PIDFS_ROOT from Linux 6.17 to bits/fcntl-linux.h

[Adhemerval Zanella]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=c0be0b4527dd97a9cbdb97f6b48471b12dcd9a94

commit c0be0b4527dd97a9cbdb97f6b48471b12dcd9a94
Author: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Date:   Fri Oct 3 16:39:04 2025 -0300

    Add FD_PIDFS_ROOT from Linux 6.17 to bits/fcntl-linux.h
    
    It was added by commit 3941e37f62fe2c3c8b8675c12183185f20450539
    
    Reviewed-by: Carlos O'Donell <carlos@redhat.com>

Diff:
---
 sysdeps/unix/sysv/linux/bits/fcntl-linux.h | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/sysdeps/unix/sysv/linux/bits/fcntl-linux.h b/sysdeps/unix/sysv/linux/bits/fcntl-linux.h
index 16c83e3349..f9b3de11f4 100644
--- a/sysdeps/unix/sysv/linux/bits/fcntl-linux.h
+++ b/sysdeps/unix/sysv/linux/bits/fcntl-linux.h
@@ -219,6 +219,9 @@
 
 /* For F_[GET|SET]FD.  */
 #define FD_CLOEXEC	1	/* Actually anything with low bit set goes */
+#ifdef __USE_GNU
+# define FD_PIDFS_ROOT	-10002	/* Root of the pidfs filesystem */
+#endif
 
 #ifndef F_RDLCK
 /* For posix fcntl() and `l_type' field of a `struct flock' for lockf().  */