Multiple outputs usable in nixpkgs

[shlevy]

I'd like to use this as a meta-issue linking to all the blockers that will need to be fixed before we can safely use multiple outputs in nixpkgs. @edolstra: could you make a list of what needs to be fixed? Or better yet make a bunch of issues and link to them here?

[edolstra]

Does GitHub even allow linking issues to each other? :-)

I've added this to the Nix 1.1 milestone.

[shlevy]

Blocked by #21

[bluescreen303]

With #21 fixed, are there any other blockers?
I would like to try getting rid of the gcc runtime dependency c++ programs have because of libstdc++.

[edolstra]

@bluescreen303 If you're going to work on that, please put it in the multiple-output branch. It already has some packages with multiple outputs (e.g. openssl, glib, ...).

[shlevy]

There are no real blockers for this anymore, right?