Upstream fixes for @yearly, @monthly, @weekly, @daily and @hourly.

Upstream fixes for @yearly, @monthly, @weekly, @daily and @hourly.
The bit_nset() macro was being called with the high value one too
large for the special strings.  There is no security impact due to
the layout of the bit strings but this was somewhat lucky.  This
introduces a set_range() function that performs range checks before
calling bit_nset().