the same width as int. This reapplies a hunk of the 2002-08-12 patch
<http://mail.gnu.org/pipermail/bison-patches/2002-August/001111.html>,
which was inadvertently undone by the 2002-09-30 patch.
bitset_windex _offset = _index - (bset)->b.cindex; \
\
if (_offset < (bset)->b.csize) \
- (bset)->b.cdata[_offset] &= ~(1 << (_bitno % BITSET_WORD_BITS)); \
+ (bset)->b.cdata[_offset] &= \
+ ~((bitset_word) 1 << (_bitno % BITSET_WORD_BITS)); \
else \
BITSET_RESET_ ((bset), _bitno); \
} while (0)