diff --git a/sys/kms/gstkmssink.c b/sys/kms/gstkmssink.c
index fa814acf5c..488c5bcbf8 100644
--- a/sys/kms/gstkmssink.c
+++ b/sys/kms/gstkmssink.c
@@ -55,6 +55,7 @@
 #include <xf86drm.h>
 #include <xf86drmMode.h>
 #include <drm_fourcc.h>
+#include <string.h>
 
 #include "gstkmssink.h"
 #include "gstkmsutils.h"