No need to assign 0 to tm_yday here.
Fix typo in comment.
Explicitly assign values for bit.t in get_bit_file().
For end-of-minute, bit.t should be increased by 1000, not set to 2000.
Rename the process_new_minute() callback to process_new_second()
Add the value of bit.t/bit.realfreq to the end of each line in the log file, preceeded by a 'c'.

This allows us to adjust the cutoff value for a new minute if necessary by providing some statistics.
Add support for log files with cutoff values in get_bit_file().
The values themselves are currently skipped.

The function treats these entries as regular input, so take some precautions:
- bit.t is set to 0 to not increase acc_minlen
- a flag GETBIT_SKIPNEXT is set when the next character of the input is 'c',
  if set the value of bitpos is not increased. This prevents falsely setting
  DT_LONG and/or GETBIT_TOOLONG
- a flag GETBIT_SKIP is set when the current character of the iput is 'c',
  if set this non-existent bit is not displayed in mainloop() (which would
  result in the last real bit being displayed twice).

Note that we cannot simply set valid to 0 in get_bit_file() because that
confuses the end-of-line handling, resulting in parsing errors.
Group the assignments of minlen in mainloop(), so that both assignments
(bitpos + 1 or 61 when GETBIT_TOOLONG) both happen after the call to
next_bit().