Security
   * Fix definition of MBEDTLS_MD_MAX_BLOCK_SIZE, which was too
     small when MBEDTLS_SHA384_C was defined and MBEDTLS_SHA512_C was
     undefined. Mbed TLS itself was unaffected by this, but user code
     which used MBEDTLS_MD_MAX_BLOCK_SIZE could be affected. The only
     release containing this bug was Mbed TLS 3.4.0.