Fix for bug #4809 (Backticks not handled in mysql)

static int

com_use(String *buffer __attribute__((unused)), char *line)

{

  char *tmp, buff[FN_REFLEN + 1];

  char tmp[FN_REFLEN], buff[FN_REFLEN + 1];

  MYSQL_RES *res;

  MYSQL_ROW row;

  char *c_buff, *c_tmp;

  while (isspace(*line))

    line++;

  strnmov(buff,line,sizeof(buff)-1);		// Don't destroy history

  if (buff[0] == '\\')				// Short command

    buff[1]=' ';

  tmp=(char *) strtok(buff," \t;");		// Skip connect command

  if (!tmp || !(tmp=(char *) strtok(NullS," \t;")))

  c_buff= buff;

  while ((*c_buff != ' ') && (*c_buff != '\t')) // Skip connect command

    c_buff++;

  c_buff++;

  while ((*c_buff == ' ') || (*c_buff == '\t'))

    c_buff++;

  c_tmp= tmp;

  if (*c_buff == '`')                           // Handling backticks

  {

    c_buff++;

    for (; *c_buff; c_tmp++)

    {

      if (*c_buff == '`')

      {

	if (c_buff[1] == '`')

	{

	  *c_tmp= '`';

	  c_buff+= 2;

	}

	else

	  break;

      }

      else

	*c_tmp= *(c_buff++);

    }

  }

  else

    for (; !strchr(" \t;", *c_buff); c_buff++, c_tmp++)

      *c_tmp= *c_buff;

  *c_tmp= '\0';

  if (!*tmp)

  {

    put_info("USE must be followed by a database name",INFO_ERROR);

    return 0;