* Fixed a warning in cacaball.c.

src/cacaball.c

@@ -14,6 +14,7 @@
 #include "config.h"
 
 #if !defined(__KERNEL__)
+#   include <string.h>
 #   include <math.h>
 #   ifndef M_PI
 #       define M_PI 3.14159265358979323846