--- a/thermferm/thermferm.h	Sat May 04 13:49:36 2024 +0200
+++ b/thermferm/thermferm.h	Sat May 04 15:18:02 2024 +0200
@@ -5,6 +5,8 @@
 #define TRUE 1
 #define FALSE 0
 
+#define _GNU_SOURCE
+
 #include "../config.h"
 #include "pid.h"