Merge branch 'maint-0.3.5' into maint-0.4.3

  o Major bugfixes (NSS):

    - When running with NSS enabled, make sure that NSS knows to expect

      nonblocking sockets. Previously, we set our TCP sockets as blocking,

      but did not tell NSS about the fact, which in turn could lead to

      unexpected blocking behavior. Fixes bug 40035; bugfix on 0.3.5.1-alpha.

    return NULL;

  }

  /* even if though the socket is already nonblocking, we need to tell NSS

   * about the fact, so that it knows what to do when it says EAGAIN. */

  PRSocketOptionData data;

  data.option = PR_SockOpt_Nonblocking;

  data.value.non_blocking = 1;

  if (PR_SetSocketOption(ssl, &data) != PR_SUCCESS) {

    PR_Close(ssl);

    return NULL;

  }

  tor_tls_t *tls = tor_malloc_zero(sizeof(tor_tls_t));

  tls->magic = TOR_TLS_MAGIC;

  tls->context = ctx;