Re: [PATCH 13/19] pack-objects: implement bitmap writing

> From: Vicent Marti <tanoku@gmail.com>
>
> This commit extends more the functionality of `pack-objects` by allowing
> it to write out a `.bitmap` index next to any written packs, together
> with the `.idx` index that currently gets written.
>
> If bitmap writing is enabled for a given repository (either by calling
> `pack-objects` with the `--write-bitmap-index` flag or by having
> `pack.writebitmaps` set to `true` in the config) and pack-objects is
> writing a packfile that would normally be indexed (i.e. not piping to
> stdout), we will attempt to write the corresponding bitmap index for the
> packfile.