diff --git a/programs/ssl/ssl_server2.c b/programs/ssl/ssl_server2.c
index 476a672..d1e45be 100644
--- a/programs/ssl/ssl_server2.c
+++ b/programs/ssl/ssl_server2.c
@@ -30,6 +30,7 @@
 #else
 #include <stdio.h>
 #include <stdlib.h>
+#define mbedtls_calloc     calloc
 #define mbedtls_free       free
 #define mbedtls_time       time
 #define mbedtls_time_t     time_t