rewrite devshell with flake

.gitignore

@@ -1 +1,4 @@
 result*
+result-*
+*~
+.DS_Store

README.md

@@ -1,7 +1,3 @@
-# rust-for-linux/nix
+# Rust for Linux Nix
 
 Efforts for packaging the Rust for Linux project with the [Nix package manager](https://nixos.org/).
-
-```
-$ nix-build -A kernel
-```

flake.nix

@@ -0,0 +1,22 @@
+{
+  description = "A very basic flake";
+
+  inputs = {
+    nixpkgs.url = "github:nixos/nixpkgs?ref=nixos-unstable";
+    flake-utils.url = "github:numtide/flake-utils";
+    oxalica.url = "github:oxalica/rust-overlay";
+  };
+
+  outputs = inputs@{ self, nixpkgs, flake-utils, ... }: {
+  } // flake-utils.lib.eachDefaultSystem (system: let
+    pkgs = import nixpkgs {
+      inherit system;
+      overlays = [ inputs.oxalica.overlays.default ];
+    };
+  in {
+    devShells = {
+      default = pkgs.callPackage ./nix/shell.nix { rustAttrs = pkgs.rust-bin.stable.latest; llvmPackages = pkgs.llvmPackages_18; };
+      clang = self.devShells.${system}.default.override { isClang = true; };
+    };
+  });
+}

nix/shell.nix

@@ -0,0 +1,109 @@
+{ lib
+, mkShellNoCC
+, writeShellScriptBin
+
+, b4
+
+, gnumake
+, pkg-config
+, ncurses
+, rustAttrs
+, rust-bindgen-unwrapped
+
+, elfutils
+, bison
+, flex
+, perl
+, bc
+, nettools
+, openssl
+, rsync
+, gmp
+, libmpc
+, mpfr
+, zstd
+, python3Minimal
+, kmod
+, hexdump
+
+, isClang ? false
+, llvmPackages
+, gcc ? null
+}:
+
+#assert !isClang -> gcc;
+
+let
+  makeBinArg = package: name: bin: "${name}=${package}/bin/${bin}";
+  makeHostToolArg = package: unwrapped: name: bin: "${makeBinArg unwrapped name bin} ${makeBinArg package "HOST${name}" bin}";
+  makeMakeVars = vars: lib.concatStringsSep " \\\n  " ((map (v:
+    if v ? package-unwrapped then
+      makeHostToolArg v.package v.package-unwrapped v.name v.bin
+    else
+      makeBinArg v.package v.name v.bin)) vars);
+  clangTool = { name, bin, hostPackage ? "clang", package ? "${hostPackage}-unwrapped" }: [
+    { inherit name; value = "${llvmPackages.${package}}/bin/${bin}"; }
+    { name = "HOST${name}"; value = "${llvmPackages.${hostPackage}}/bin/${bin}"; }
+  ];
+
+  # Env variables that make wants
+  makeEnv = if isClang then ({
+    LLVM = "1";
+    NM = "${llvmPackages.libllvm}/bin/llvm-nm";
+    STRIP = "${llvmPackages.libllvm}/bin/llvm-strip";
+    OBJCOPY = "${llvmPackages.libllvm}/bin/llvm-objcopy";
+    READELF = "${llvmPackages.libllvm}/bin/llvm-readelf";
+    LLVM_AS = "${llvmPackages.libllvm}/bin/llvm-as";
+    LLVM_LINK = "${llvmPackages.libllvm}/bin/llvm-link";
+    KCFLAGS = "\"-isystem ${llvmPackages.clang}/resource-root/include\"";
+  } // (lib.listToAttrs (lib.flatten (map clangTool [
+    { name = "CC"; bin = "clang"; }
+    { name = "LD"; bin = "ld.lld"; hostPackage = "bintools"; }
+    { name = "AR"; bin = "ar"; hostPackage = "bintools"; }
+  ])))) else {
+    TODO = builtins.warn "TODO gcc build";
+  };
+
+  gnumake' = writeShellScriptBin "make" ''
+    ${gnumake}/bin/make "$@" \
+      ${lib.concatStringsSep " \\\n  " (lib.mapAttrsToList (name: value: "${name}=${value}") makeEnv)}
+  '';
+in mkShellNoCC {
+  name = "linux";
+
+  packages = [
+    b4
+
+    gnumake'
+    pkg-config
+    ncurses
+
+    elfutils
+    bison
+    flex
+    perl
+    bc
+    nettools
+    openssl
+    rsync
+    gmp
+    libmpc
+    mpfr
+    zstd
+    python3Minimal
+    kmod
+    hexdump
+
+    (rustAttrs.default.override {
+      extensions = [ "rust-src" "rust-analyzer" ];
+    })
+    rust-bindgen-unwrapped
+  ];
+
+  env = makeEnv;
+
+  LIBCLANG_PATH = "${llvmPackages.libclang.lib}/lib";
+
+  hardeningDisable =
+    [ "bindnow" "format" "fortify" "stackprotector" "pic" "pie" ];
+}