(bitset_bytes, bitset_alloc, bitset_obstack_alloc):

(bitset_bytes, bitset_alloc, bitset_obstack_alloc):
Use size_t, not unsigned int, to count bytes.

(bitset_print): Use proper printf format for bitset types.

(bitset_next, bitset_prev, bitset_first, bitset_last):
Return BITSET_BINDEX_MAX (not -1) for no value,
since we now return the bitset_bindex type (not int).