Earlier quoted context omitted.
The goal of the [nix]( http://nixos.org/ ) project is to solve this, and every time anyone brings up a package manager on HN, someone has to mention nix. The reality is that nix is really nice, but isn't any better than making a new package manager until it has wide adoption, so no one is using it.
It seems to be only for GNU/Linux systems, what about all other OSs out there?
The good news is that you can integrate your language-specific tools with Nix as well, such as has been done for Haskell, node.js and other things. (I'm looking at it so that we can integrate our Dylan stuff with it.)