made more pointers unsigned, as they were mostly used passed in to functions

struct send_request {

  /* Remaining data to send */

  const char *data;

  const unsigned char *data;

  int len;

  /* Next request in queue */

  time_t timeout;

  /* Query buf with length at beginning, for TCP transmission */

  char *tcpbuf;

  unsigned char *tcpbuf;

  int tcplen;

  /* Arguments passed to ares_send() (qbuf points into tcpbuf) */

  const char *qbuf;

  const unsigned char *qbuf;

  int qlen;

  ares_callback callback;

  void *arg;