diff --git a/mozilla/intl/locale/src/os2/nsCollationOS2.cpp b/mozilla/intl/locale/src/os2/nsCollationOS2.cpp
index 0bd06c38f67..ed8f7482f47 100644
--- a/mozilla/intl/locale/src/os2/nsCollationOS2.cpp
+++ b/mozilla/intl/locale/src/os2/nsCollationOS2.cpp
@@ -39,6 +39,7 @@
 #include "nsIOS2Locale.h"
 #include "nsCOMPtr.h"
 #include "nsString.h"
+#include "nsCRT.h"
 
 NS_IMPL_ISUPPORTS1(nsCollationOS2, nsICollation)