--- atop-2.12.1.orig/cgroups.c	2025-09-23 19:16:03.000000000 +0200
+++ atop-2.12.1/cgroups.c	2026-07-07 02:03:50.342212381 +0200
@@ -27,7 +27,7 @@
 ** Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 ** --------------------------------------------------------------------------
 */
-#define _POSIX_C_SOURCE
+#define _POSIX_C_SOURCE 200809L
 #define _XOPEN_SOURCE
 #define _GNU_SOURCE
 #define _DEFAULT_SOURCE
