Chris Billington writes:
> - upstream uses git submodules for pugixml, SingleApplication, and the 
> 'elements' library. I have used the same pinned revisions in 
> SITES.xxx/DISTFILES.xxx as the upstream branch.

DIST_TUPLE would be a better fit for this.

> - The 'elements' user-submitted library (CC-BY-SA 3.0) is pinned against 
> a 9-month-old commit of the submodule repo.
> Is it permissible to use a recent commit instead, since that would still 
> make a reproducible build but would include more recent items?

If doing so provides value and doesn't introduce incompatibility, then
sure.

> - portcheck notes 3 Makefile lines longer than 80 chars, but it's not 
> easy to break them without sacrificing readability. Is that acceptable?

Yes.