diff --git a/crypto/bn/bn_lib.c b/crypto/bn/bn_lib.c
index 096bcf183583d6c3d189abb65395bd3b6b266437..c71f0b0863e530564310505480d712f1409aa087 100644
--- a/crypto/bn/bn_lib.c
+++ b/crypto/bn/bn_lib.c
@@ -62,6 +62,7 @@
 #endif
 
 #include <assert.h>
+#include <limits.h>
 #include <stdio.h>
 #include "cryptlib.h"
 #include "bn_lcl.h"