Changes
   * The ECP module, enabled by `MBEDTLS_ECP_C`, now depends on
     `MBEDTLS_CTR_DRBG_C` or `MBEDTLS_HMAC_DRBG_C` for some side-channel
     coutermeasures. If side channels are not a concern, this dependency can
     be avoided by enabling the new option `MBEDTLS_ECP_NO_INTERNAL_RNG`.