message: core: wait for at least 1 byte
  We want to wait for at least 1 byte, otherwise this is basically still a
  nonblocking read and results in a busy loop.
diff: @@ -82,8 +82,8 @@ DroneCore::ConnectionResult SerialConnection::setup_port()
  tc.c_cflag &= ~(CSIZE | PARENB | CBAUD | CRTSCTS);
  tc.c_cflag |= CS8 | BOTHER;
  - tc.c_cc[VMIN] = 0;
  - tc.c_cc[VTIME] = 0;
  + tc.c_cc[VMIN] = 1; // We want at least 1 byte to be available.
  + tc.c_cc[VTIME] = 0; // We don't timeout but wait indefinitely.
  tc.c_ispeed = _baudrate;
  tc.c_ospeed = _baudrate;
  