--- a/src/silly.c	2020-06-05 17:42:19.000000000 +0700
+++ b/src/silly.c	2020-09-29 11:54:29.000000000 +0700
@@ -14,4 +14,5 @@
 #include <stdlib.h>
 #include <math.h>
+#include <string.h>
 
 #ifndef WIN32