The `->util` field corresponding to each string_list_item is used to
track the existence of some pack at the beginning of a repack operation
was originally intended to be used as a bitfield.
This bitfield tracked:
- (1 << 0): whether or not the pack should be deleted
- (1 << 1): whether or not the pack is cruft
The previous commit removed the use of the second bit, but a future
patch (from a different series than this one) will introduce a new use
of it.
So we could stop treating the util pointer as a bitfield and instead
start treating it as if it were a boolean. But this would require some
backtracking when that later patch is applied.
Instead, let's avoid touching the ->util field directly, and instead
introduce convenience functions like:
Helped-by: Junio C Hamano <gitster@pobox.com> Helped-by: Jeff King <peff@peff.net> Helped-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>