diff --git a/crypto/bn/bn_local.h b/crypto/bn/bn_local.h
index ec90338510..1c9c018cf2 100644
--- a/crypto/bn/bn_local.h
+++ b/crypto/bn/bn_local.h
@@ -22,6 +22,7 @@
 # endif
 
 # include "crypto/bn.h"
+# include "internal/cryptlib.h"
 
 /*
  * These preprocessor symbols control various aspects of the bignum headers