diff --git a/cf/crypto.m4 b/cf/crypto.m4
index 5fa3b1008..6c5967938 100644
--- a/cf/crypto.m4
+++ b/cf/crypto.m4
@@ -11,6 +11,7 @@ m4_define([test_headers], [
 		#include <openssl/md4.h>
 		#include <openssl/md5.h>
 		#include <openssl/sha.h>
+		#define OPENSSL_DES_LIBDES_COMPATIBILITY
 		#include <openssl/des.h>
 		#include <openssl/rc4.h>
 		#include <openssl/rand.h>