draft: package c2rust as a "nix flake"

flake.nix

@@ -0,0 +1,74 @@
+{
+  description = "help migrate C99-compliant code to Rust";
+
+  inputs.crane.url = "github:ipetkov/crane";
+  inputs.crane.inputs.flake-utils.follows = "flake-utils";
+  inputs.crane.inputs.nixpkgs.follows = "nixpkgs";
+
+  inputs.flake-utils.url = "github:numtide/flake-utils";
+
+  inputs.nixpkgs.url = "nixpkgs/nixpkgs-unstable";
+
+  inputs.rust-overlay.url = "github:oxalica/rust-overlay";
+  inputs.rust-overlay.inputs.flake-utils.follows = "flake-utils";
+  inputs.rust-overlay.inputs.nixpkgs.follows = "nixpkgs";
+
+  outputs = {self, nixpkgs, crane, rust-overlay, flake-utils}:
+    flake-utils.lib.simpleFlake {
+      inherit self nixpkgs;
+      name = "c2rust";
+      systems = flake-utils.lib.allSystems;
+      preOverlays = [ rust-overlay.overlay ];
+      overlay = final: prev: {
+        c2rust = rec {
+          c2rust = lib.c2rust { isShell = false; };
+          devShell = lib.c2rust { isShell = true; };
+          defaultPackage = c2rust;
+
+          rust = with final; with pkgs; (rust-bin.nightly."2022-02-14".minimal.override {
+            extensions = [ "rustfmt-preview" "rust-src" "rustc-dev" "llvm-tools-preview" ];
+	  });
+
+          lib.c2rust = { isShell, subpkg ? "c2rust", subdir ? "." }:
+            let
+              buildInputs = with final; with pkgs; [
+                rust
+                llvmPackages_latest.clang
+                llvmPackages_latest.libclang
+                cmake
+                llvmPackages_latest.llvm
+                openssl
+                pkgconfig
+                python3
+                rustup
+                zlib
+                curl
+              ] ++ final.lib.optionals isShell [
+                entr
+              ] ++ final.lib.optionals stdenv.isDarwin (with darwin.apple_sdk.frameworks; [
+                Security
+              ]) ++ final.lib.optionals stdenv.isLinux ([
+              ]);
+            in with final; with pkgs; crane.lib.${final.system}.buildPackage {
+            pname = "${subpkg}";
+            version = "0.1";
+
+            src = self;
+
+            inherit buildInputs;
+            dontUseCmakeConfigure = true;
+            RUST_SYSROOT = "${rust}";
+            cargoExtraArgs = "--features dynamic-instrumentation";
+
+            preFixup = final.lib.optionalString stdenv.isDarwin ''
+              if [ -f "$out/bin/c2rust-instrument" ]; then
+                install_name_tool -add_rpath "${rust}/lib" "$out/bin/c2rust-instrument"
+              fi
+            '';
+
+            doCheck = false;
+          };
+        };
+      };
+    };
+}