makeWrapper as part of stdenv/setup.sh?

[jonringer]

I would say it's used almost as commonly as something like substituteInPlace, not sure if we should just move makeWrapper and wrapProgram logic into stdenv. This avoids people having to add it separately, and with #7, it makes it more of something which is available through stdenv.mkDerivation.

For compatibility with nixpkgs, we could add makeWrapper = null;