Add a verbose-on option.

[desumn]

Implementation of #5331

Add a verbose-on=PACKAGES parameters to build options. For the time being, it's equivalent to a simple -v for a list of package.

I'm not sure how I'd be able to simulate a modification of the opam file of a specific package to change add the verbose flag, so it's not exactly what #5331 asked for, however if there's a way I'd be glad to implement it!

[rjbou]

Thanks a lot for this first PR!
I've put some comments, but the general idea on how you add it is good!
Please tell me if you need more precision!

[rjbou]

Here you have verbose_on and a name & version opt list, but only names are used. It'll be better to take only name list. You can use OpamArg.name_list

Suggested change

	Arg.(some (list package)) None ~vopt:(Some [])
	Arg.(some name_list) None ~vopt:(Some [])

[rjbou]

I've added a test (tests/reftests/verbose-on.test), like that you can it is possible to test your feature, and we'll keep it as a new test in the testsuite, to be sure to detect regression in PRs.

I've also rebased your PR, we prefer rebasing on master than merging master for PRs, it eases history/commits lookup.

[desumn]

Thanks for your review, I did it a bit late... but I think there's nothing more to do about what you said, I'll however say I don't exactly know how to test env variables, and I'm not sure if what I did works (at least it compiles!)

[rjbou]

No worry! We'll try to review the changes in the next weeks. We are also focused on the 2.2 release on our side :)

[desumn]

It's been some time, do you have any update on this?

[rjbou]

Sorry for the delay, we are still diving into the release of 2.2 (that is in its beta2 since 2 days). I've put some comments, with these modification and an update of master_changes (points to add in Client, Reftests, and API), the PR should be nearly complete.

[desumn]

Thanks for your reviews, I commited the changes.