Re: [PATCH v2 5/5] parse-options: detect mismatches in integer signedness

> Address the systemic issue by introducing two new build asserts
> `BARF_UNLESS_SIGNED()` and `BARF_UNLESS_UNSIGNED()`. As the names
> already hint at, those macros will cause a compiler error when passed a
> value that is not signed or unsigned, respectively.
>
> Adapt `OPT_INTEGER()`, `OPT_UNSIGNED()` as well as `OPT_MAGNITUDE()` to
> use those asserts. This uncovers a small set of sites where we indeed
> have the same bug as in git-backfill(1). Adapt all of them to use the
> correct option.