Fix ssl_client2 and ssl_server2 if !PLATFORM_C
The CA callback changes introduce mbedtls_calloc() and
mbedtls_free() to ssl_client2 and ssl_server2, which
wasn't defined unless MBEDTLS_PLATFORM_C was set.
diff --git a/programs/ssl/ssl_client2.c b/programs/ssl/ssl_client2.c
index 2e99e96..d4c73fc 100644
--- a/programs/ssl/ssl_client2.c
+++ b/programs/ssl/ssl_client2.c
@@ -35,6 +35,8 @@
#define mbedtls_printf printf
#define mbedtls_fprintf fprintf
#define mbedtls_snprintf snprintf
+#define mbedtls_calloc calloc
+#define mbedtls_free free
#define mbedtls_exit exit
#define MBEDTLS_EXIT_SUCCESS EXIT_SUCCESS
#define MBEDTLS_EXIT_FAILURE EXIT_FAILURE
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