diff --git a/ssl/ssl_lib.c b/ssl/ssl_lib.c
index d606c7f..34e88fd 100644
--- a/ssl/ssl_lib.c
+++ b/ssl/ssl_lib.c
@@ -138,6 +138,8 @@
  * OTHER ENTITY BASED ON INFRINGEMENT OF INTELLECTUAL PROPERTY RIGHTS OR
  * OTHERWISE. */
 
+#include <openssl/ssl.h>
+
 #include <assert.h>
 #include <stdio.h>
 #include <string.h>