Contributed patches for `port environment` and a more generalised `port info --var`

[René J.V. Bertin]

Hi,

A while back someone (or 2 someones) on here went ahead and implemented ideas I raised:

- `port environment` to dump an overview of the environment and context used when running Portfiles (not exactly what I was looking for but still useful from time to time)

- a more generalised `port info --var` implementation, which notably allows to dump the patchfiles used depending on variant (as far as that's truly possible). This is an option I use quite regularly, even if most of the time I simply look at the patchfiles in the .state file, where they're listed thanks to a patch of my own (submitted on trac).

I haven't kept the emails from back then (= can't find them), and neither of the above have made it to master. I don't want to submit patches I didn't write myself, not before knowing what their author(s) think about incorporating them.

R.