Fix typo in platform macro defines for examples
diff --git a/programs/ssl/ssl_mail_client.c b/programs/ssl/ssl_mail_client.c
index a414864..04f8910 100644
--- a/programs/ssl/ssl_mail_client.c
+++ b/programs/ssl/ssl_mail_client.c
@@ -34,7 +34,7 @@
 #define mbedtls_time_t          time_t
 #define mbedtls_fprintf         fprintf
 #define mbedtls_printf          printf
-#define MBEDTLS_EXTI_SUCCESS    EXIT_SUCCESS
+#define MBEDTLS_EXIT_SUCCESS    EXIT_SUCCESS
 #define MBEDTLS_EXIT_FAILURE    EXIT_FAILURE
 #endif /* MBEDTLS_PLATFORM_C */