diff --git a/indra/llmath/v3color.h b/indra/llmath/v3color.h
index 56cb2ae73e57be7f0cdce9c1065479a965819cf6..daf3a6857b489c5f01701ebfb9bbb66169b0c4de 100644
--- a/indra/llmath/v3color.h
+++ b/indra/llmath/v3color.h
@@ -33,6 +33,7 @@ class LLVector4;
 #include "llerror.h"
 #include "llmath.h"
 #include "llsd.h"
+#include <string.h>
 
 //  LLColor3 = |r g b|