--- atop-2.12.1.orig/atopacctd.c	2025-09-23 19:16:03.000000000 +0200
+++ atop-2.12.1/atopacctd.c	2026-07-07 02:05:12.758517636 +0200
@@ -36,7 +36,7 @@
 ** it under the terms of the GNU General Public License version 2 as
 ** published by the Free Software Foundation.
 */
-#define _POSIX_C_SOURCE
+#define _POSIX_C_SOURCE 200809L
 #define _XOPEN_SOURCE
 #define _GNU_SOURCE
 #define _DEFAULT_SOURCE
