Resynchronise pkgs/dmd with Nixpkgs dmd.

[dukc]

An year ago or so, the generic.nix and binary.nix in OldDDerivations were basically the same as in Nixpkgs. It was easy to upstream and downstream any improvements, Nixpkgs only lacking the version-specific hash files.

If possible, I would like to reintroduce this synergy. Obviously this does depend on reaching agreement with other Nixpkgs maintainers (I'm one of the dmd maintainers there though so I should have some power). However, I think we should first get DMD versions from 2.084.1 (oldest in OldDDerivations) to the latest stable working first, otherwise people in Nixpkgs don't have much reason to accept any changes from here.

[nekowinston]

There's currently an open PR for nixpkgs#dmd (NixOS/nixpkgs#111525) that slims down the package, would be nice if this could get added here if needed. I haven't been able to try this repo's dmd package yet, since dmd is x86 exclusive.

[dukc]

Agreed.