diff --git a/indra/llcommon/llstring.h b/indra/llcommon/llstring.h
index d728221b54c8280f20ddaeebe226827a1cfdfa30..1a1dbd40b6d2a99ba8a23bae4b888f1e7c78e227 100644
--- a/indra/llcommon/llstring.h
+++ b/indra/llcommon/llstring.h
@@ -49,6 +49,8 @@ const char LL_UNKNOWN_CHAR = '?';
 
 #if LL_DARWIN || LL_LINUX || LL_SOLARIS
 // Template specialization of char_traits for U16s. Only necessary on Mac and Linux (exists on Windows already)
+#include <cstring>
+
 namespace std
 {
 template<>