Do work on curl/mbedtls/zstd

This change fixes stderr to be unbuffered. Added hardware AES on ARM64
to help safeguard against timing attacks. The curl.com command will be
somewhat more pleasant to use.

third_party/mbedtls/aes.h

@@ -46,12 +46,14 @@ mbedtls_aes_context;
 typedef struct mbedtls_aes_xts_context
 {
     mbedtls_aes_context crypt; /*!< The AES context to use for AES block
-                                        encryption or decryption. */
+                                    encryption or decryption. */
     mbedtls_aes_context tweak; /*!< The AES context used for tweak
-                                        computation. */
+                                    computation. */
 } mbedtls_aes_xts_context;
 #endif /* MBEDTLS_CIPHER_MODE_XTS */
 
+int mbedtls_aes_uses_hardware( void );
+
 /**
  * \brief          This function initializes the specified AES context.
  *