When packaging Siad (https://github.com/NebulousLabs/Sia) I'm getting missing dependencies when I nix-build the result.

• default.nix: https://github.com/NixOS/nixpkgs/compare/master...grahamc:sia?expand=1#diff-2ca016fb77cf0742c3396dc243dd0c6cR1 (modified to add subPackages = [ "siad" ];)
• deps.nix: https://github.com/NixOS/nixpkgs/compare/master...grahamc:sia?expand=1#diff-5549d2234c56be4ae44c96a69f071d87R1
• how I made these files: https://github.com/NixOS/nixpkgs/compare/master...grahamc:sia?expand=1#diff-1f8b3ed888bf7049648315e826cb5856R11

Interestingly they have a makefile: https://github.com/NebulousLabs/Sia/blob/master/Makefile but after the go get (without calling make) the resulting binary works fine. However, the nix package isn't correct and does not compile due to missing dependencies.