diff --git a/crypto/ecdh/ecdh.h b/crypto/ecdh/ecdh.h
index cc6d858d6..db6fd4870 100644
--- a/crypto/ecdh/ecdh.h
+++ b/crypto/ecdh/ecdh.h
@@ -69,6 +69,8 @@
 #ifndef HEADER_ECDH_H
 #define HEADER_ECDH_H
 
+#include <openssl/opensslconf.h>
+
 #ifdef OPENSSL_NO_ECDH
 #error ECDH is disabled.
 #endif