[racket] info.rkt `deps` (was: Package fails to compile during 'make in-place' but not 'raco pkg install')

>> Does `raco setup` not show this when run as part of `raco pkg install`?
>
> Yes, in fact that difference is the topic of the message from Matthew
> that you replied to when starting this sub-thread. ;)

Um, brain buffer overflow?

So: In my .travis.yml files I already run `raco pkg install`. What I
think I will do is also run `raco setup` to look for undeclared
dependencies. If that gives a non-zero exit code for undeclared deps,
done. Otherwise I guess I'll grep the output for "raco setup:
undeclared dependency detected". Either way, I make Travis say "build
status: failed".

That way I'll be alerted if the deps are wrong for a new package, or
after changing an existing one, or even for pull requests from other
folks (since Travis automatically runs on PRs, too).