Note that there is Meteotime information available in dcf77pi-analyze
Add a function setclock_ok() in setclock.* and use it in dcf77pi.c
Actually clean up when exiting readpin.c with SIGINT by installing a handler for it.
Make acc_minlen a first-class entity in decode_time.

Remove it as an argument from the print_minute callback function in mainloop().
Remove it as a parameter from decode_time().
lint(1) fix: do not mask some(?) external declaration of "time".
For live decoding, increase acc_minlen by the actually measured bit length in milliseconds instead of 1000 or 2500 for a radio error.

Use dummy values when decoding from a file.
Clear newtime structure to prevent nonsense values when acc_minlen is somehow < 59000.
lint(1) fix, use an explicit cast.