Able to build zephyr toolchains

flake.nix

@@ -6,14 +6,11 @@
     utils.url = "github:numtide/flake-utils";
   };
 
-  outputs = { self, nixpkgs, utils }: utils.lib.eachDefaultSystem (system:
-    let
-      pkgs = import nixpkgs { inherit system; };
-    in
-    {
-      packages = {
-        zephyr = pkgs.callPackage ./packages/zephyr { };
-      };
+  outputs = { self, nixpkgs, utils }:
+    utils.lib.eachDefaultSystem (system:
+      let pkgs = import nixpkgs { inherit system; };
+      in {
+        packages = { zephyr = pkgs.callPackage ./packages/zephyr { }; };
 
         formatter = pkgs.nixfmt;
       });

packages/zephyr/default.nix

@@ -1,8 +1,14 @@
 { callPackage, stdenv, lib }:
 let assets = lib.importJSON ./assets.json;
-in {
+in rec {
   host-tools = callPackage ./host-tools.nix {
     inherit (assets) version hosts;
     sources = assets.host_tools;
   };
+
+  toolchains = lib.mapAttrs (target: sources:
+    callPackage ./toolchain.nix {
+      inherit target sources;
+      inherit (assets) version hosts;
+    }) assets.toolchains;
 }

packages/zephyr/toolchain.nix

@@ -0,0 +1,42 @@
+{ stdenv, lib, fetchurl, autoPatchelfHook, target, sources, version, hosts }:
+
+stdenv.mkDerivation {
+  pname = "zephyr-toolchain-${target}";
+  inherit version;
+
+  src = fetchurl (sources."${stdenv.hostPlatform.system}");
+
+  dontConfigure = true;
+  dontUnpack = true;
+  dontBuild = true;
+  # If we're building the same architecture as the target it will mess with files like
+  # crt1.o, so use autopatchelf and only some files
+  dontPatchELF = true;
+  dontAutoPatchelf = true;
+  nativeBuildInputs = [ autoPatchelfHook ];
+  autoPatchelfIgnoreMissingDeps = [ "libpython*" ];
+
+  installPhase = ''
+    runHook preInstall
+    mkdir -p "$out"
+    tar -C "$out" -xvf "$src"
+    runHook postInstall
+  '';
+
+  preFixup = ''
+    autoPatchelf ${target}/bin
+    autoPatchelf ${target}/${target}/bin
+    autoPatchelf ${target}/lib/bfd-plugins
+    autoPatchelf ${target}/lib/gcc/${target}/*/plugin ${target}/libexec/gcc/${target}
+    echo "done with my autopatchelf"
+  '';
+
+  meta = with lib; {
+    homepage = "https://www.zephyrproject.org/";
+    description =
+      "Toolchain for building Zephyr for the ${target} architecture";
+    license = licenses.asl20;
+    platforms = hosts;
+    maintainers = with maintainers; [ artemist ];
+  };
+}