external & build dependences in src tree

- external & build dependences boost licensed
  - ext_depends (external depends)
    - D-YAML
      - tinyendian
    - d2sqlite3
    - imageformats
  - build_depends
    - dub2nix

1 files changed, 82 insertions, 0 deletions

diff --git a/src/build_depends/dub2nix/README.md b/src/build_depends/dub2nix/README.md
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+# dub2nix
+CLI tool to create Nix expressions for D-lang Dub projects.
+
+![CI](https://github.com/lionello/dub2nix/workflows/CI/badge.svg)
+
+## Installation
+Install with `nix-env`:
+```sh
+nix-env -if https://github.com/lionello/dub2nix/archive/master.tar.gz
+```
+or add to your `shell.nix` and run `nix-shell`:
+```nix
+with import <nixpkgs> {};
+let
+  dub2nix-src = fetchTarball {
+    url = "https://github.com/lionello/dub2nix/archive/master.tar.gz";
+  };
+  dub2nix = (import dub2nix-src) { inherit pkgs; };
+in mkShell {
+  buildInputs = [
+    dub2nix # dub dmd rdmd ldc etc..
+  ];
+}
+```
+
+## Development
+Do `git clone` and `nix-shell` to build with `dub`:
+```sh
+nix-shell
+dub
+```
+Alternatively, use `direnv`:
+```sh
+echo use nix >> .envrc
+direnv allow
+dub
+```
+
+## Usage
+```
+Usage: dub2nix [OPTIONS] COMMAND
+
+Create Nix derivations for Dub package dependencies.
+
+Commands:
+  save         Write Nix files for Dub project
+
+Options:
+-i     --input Path of selections JSON; defaults to ./dub.selections.json
+-o    --output Output Nix file for Dub project
+-r  --registry URL to Dub package registry; default http://code.dlang.org/packages/
+-d --deps-file Output Nix file with dependencies; defaults to ./dub.selections.nix
+-h      --help This help information.
+```
+First, use `dub build` to generate the `dub.selections.json` for your Dub project.
+Then, run `dub2nix save` to read the `dub.selections.json` in the current folder and write a new file `dub.selections.nix`.
+
+This `dub.selections.nix` is used in `mkDubDerivation` (from `mkDub.nix`) to create a new derivation for your Dub project:
+```nix
+{pkgs}:
+with (import ./mkDub.nix {
+    inherit pkgs;
+});
+mkDubDerivation {
+    version = "0.1.0"; # optional
+    src = ./.;
+}
+```
+
+When your project has no dependencies at all, this will fail because `dub.selections.nix` is missing. Set `deps` to override the dependencies:
+```nix
+{pkgs}:
+with (import ./mkDub.nix {
+    inherit pkgs;
+});
+mkDubDerivation {
+    src = ./.;
+    deps = [];
+}
+```
+
+Use the `--output` option to write a `.nix` file with a skeleton derivation for your dub project. This will also create the `mkDub.nix` file for importing into the derivation.