Fixups for f9029f3e9661ad9bce39907422b1a4e02272d96f

Make sure announcements work again.
Transform wday[] into a function get_weekday() to prevent duplicated definitions when including/linking against decode_time.h
Remove unused "flags" parameter from add_minute() which propagated into the otherwise unused parameter "old_dt"
- Refactor code to fill the civil warning buffer into fill_civil_buffer()
- Rename buf[] in decode_alarm.c to civbuf[] and internalize it
- Introduce CIVBUFLEN
- Introduce init_alarm(), get_civil_buffer() and get_civil_status()
- Cleanup some variables in dcf77pi*.c, convert if statements into a switch
dcf77pi-analyze: Make 'bitpos' local to main()