diff --git a/dansguardian/src/authplugins/ntlm.cpp b/dansguardian/src/authplugins/ntlm.cpp

index 8fc2982..b95fa06 100644

--- a/dansguardian/src/authplugins/ntlm.cpp

+++ b/dansguardian/src/authplugins/ntlm.cpp

@@ -23,6 +23,7 @@

 	#include "dgconfig.h"

 #endif

+#include <stddef.h>

 #include "../Auth.hpp"

 #include "../FDTunnel.hpp"

 #include "../OptionContainer.hpp"