NIXPKG1 http://nixos.org/releases/nixpkgs/nixpkgs-0.12/MANIFEST bison-2.3 x86_64-linux /nix/store/9dkca31jp4wlv0xhc7z0q6l90hl1rjgj-bison-2.3.drv /nix/store/0z395g1hsgs87v5gf066c9kwvp7496za-bison-2.3