doc: add modRoot package option for building Go modules

[mbbx6spp]

Motivation for this change

Update nixpkgs language packaging documentation referencing and explaining what modRoot to building Go modules.

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS linux)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Determined the impact on package closure size (by running nix path-info -S before and after)
• Ensured that relevant documentation is up to date
• Fits CONTRIBUTING.md.

[SuperSandro2000]

The default is . so we do not need to specify it.

[mbbx6spp]

This specific doc example it is "." but it is common to need to override with Go modules so it should be in the documentation.

[mbbx6spp]

Maybe we add a special note so people don't have to go into the Nix lambda (which they often won't) to look up how to set this up for typical Go modules (not the most basic pet example here)? This is a very basic example that doesn't represent a lot of Go modules in the wild.

[SuperSandro2000]

This specific doc example it is "." but it is common to need to override with Go modules so it should be in the documentation.

Maybe we find a better example where it isn't the default value?

Maybe we add a special note so people don't have to go into the Nix lambda

What do you mean exactly?

[stale]

I marked this as stale due to inactivity. → More info