diff --git a/src/cursor.c b/src/cursor.c
index e7a4a5d7..53de192b 100644
--- a/src/cursor.c
+++ b/src/cursor.c
@@ -1,4 +1,5 @@
 // SPDX-License-Identifier: GPL-2.0-only
+#define _POSIX_C_SOURCE 200809L
 #include <assert.h>
 #include <linux/input-event-codes.h>
 #include <sys/time.h>