diff --git a/simulat0r/firmware/basic/delayms.c b/simulat0r/firmware/basic/delayms.c
index c0d69d3..2588a99 100644
--- a/simulat0r/firmware/basic/delayms.c
+++ b/simulat0r/firmware/basic/delayms.c
@@ -3,7 +3,8 @@
 
 /* Simulator improved version */
 
-#define _POSIX_C_SOURCE 199309
+#define _POSIX_C_SOURCE 199309L
+#define __USE_POSIX199309
 #include <time.h>
  
 void delayms(uint32_t ms)