diff --git a/libvo/aclib.c b/libvo/aclib.c
index 07f297f41f..13bb3df643 100644
--- a/libvo/aclib.c
+++ b/libvo/aclib.c
@@ -8,6 +8,7 @@
   runtime cpu detection by michael niedermayer (michaelni@gmx.at) is under GPL
 */
 #include <stddef.h>
+#include <string.h>
 #include "cpudetect.h"
 #include "fastmemcpy.h"
 #undef memcpy