Convert statusbar() to a function that shall be threaded, merge check_timer() into it.

Use nanosleep() on the thread to wait instead of counting bitpos.
Convert setclock() to use the new statusbar() function and use the correct type for "time" parameter.

FIXME: crashes a while after displaying the "Setting time" message.
Use tzset() to initialize the time zone for the mktime() call.

On UTC clocks the time is still either an hour ahead or -1.