Add missing platform macro defines in cert_app.c
diff --git a/programs/x509/cert_app.c b/programs/x509/cert_app.c
index 7ad4e86..c57ecca 100644
--- a/programs/x509/cert_app.c
+++ b/programs/x509/cert_app.c
@@ -30,11 +30,13 @@
#else
#include <stdio.h>
#include <stdlib.h>
-#define mbedtls_time time
-#define mbedtls_time_t time_t
-#define mbedtls_fprintf fprintf
-#define mbedtls_printf printf
-#endif
+#define mbedtls_time time
+#define mbedtls_time_t time_t
+#define mbedtls_fprintf fprintf
+#define mbedtls_printf printf
+#define MBEDTLS_EXIT_SUCCESS EXIT_SUCCESS
+#define MBEDTLS_EXIT_FAILURE EXIT_FAILURE
+#endif /* MBEDTLS_PLATFORM_C */
#if !defined(MBEDTLS_BIGNUM_C) || !defined(MBEDTLS_ENTROPY_C) || \
!defined(MBEDTLS_SSL_TLS_C) || !defined(MBEDTLS_SSL_CLI_C) || \