diff --git a/Cryptlib/Include/OpenSslSupport.h b/Cryptlib/Include/OpenSslSupport.h
index f73bbc9..fff6a52 100644
--- a/Cryptlib/Include/OpenSslSupport.h
+++ b/Cryptlib/Include/OpenSslSupport.h
@@ -23,6 +23,11 @@ WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
 #include <Library/MemoryAllocationLib.h>
 #include <Library/DebugLib.h>
 
+/*
+ * Include stddef.h to avoid redefining "offsetof"
+ */
+#include <stddef.h>
+
 #define CONST const
 
 //