tcpto.c: initialize firstwhen variable

[mbhangui]

Initialize firstwhen variable in tcpto.c and fix compiler warning

[mbhangui]

have reduced the scope of the variable

[moon-chilled]

The compiler warning is wrong—firstwhen will never be used uninitialized—and actually initializing firstwhen obscures that fact.

I think it would be better to refactor the whole loop, if you really want to avoid the warning; something like this maybe:

if (i >= n && n == 0)
  i = -1;
else if (i >= n)
 {
  int firstpos;
  datetime_sec firstwhen;
  record = tcpto_buf;
  firstpos = 0;
  firstwhen = when = extract_record(&record);
  for (i = 1;i < n;++i)
   {
    when = extract_record(&record);
    if ((firstpos < 0) || (when < firstwhen))
     {
      firstpos = i;
      firstwhen = when;
     }
   }
  i = firstpos;
 }