flake: add missing attributes on rustc (for nixpkgs-unstable compat)

flake.lock

@@ -1,28 +1,12 @@
 {
   "nodes": {
-    "mozilla-overlay": {
-      "flake": false,
-      "locked": {
-        "lastModified": 1704373101,
-        "narHash": "sha256-+gi59LRWRQmwROrmE1E2b3mtocwueCQqZ60CwLG+gbg=",
-        "owner": "mozilla",
-        "repo": "nixpkgs-mozilla",
-        "rev": "9b11a87c0cc54e308fa83aac5b4ee1816d5418a2",
-        "type": "github"
-      },
-      "original": {
-        "owner": "mozilla",
-        "repo": "nixpkgs-mozilla",
-        "type": "github"
-      }
-    },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1727540905,
-        "narHash": "sha256-40J9tW7Y794J7Uw4GwcAKlMxlX2xISBl6IBigo83ih8=",
+        "lastModified": 1731652201,
+        "narHash": "sha256-XUO0JKP1hlww0d7mm3kpmIr4hhtR4zicg5Wwes9cPMg=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "fbca5e745367ae7632731639de5c21f29c8744ed",
+        "rev": "c21b77913ea840f8bcf9adf4c41cecc2abffd38d",
         "type": "github"
       },
       "original": {
@@ -34,8 +18,29 @@
     },
     "root": {
       "inputs": {
-        "mozilla-overlay": "mozilla-overlay",
-        "nixpkgs": "nixpkgs"
+        "nixpkgs": "nixpkgs",
+        "rust-overlay": "rust-overlay"
+      }
+    },
+    "rust-overlay": {
+      "inputs": {
+        "nixpkgs": [
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1719454714,
+        "narHash": "sha256-MojqG0lyUINkEk0b3kM2drsU5vyaF8DFZe/FAlZVOGs=",
+        "owner": "oxalica",
+        "repo": "rust-overlay",
+        "rev": "d1c527659cf076ecc4b96a91c702d080b213801e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "oxalica",
+        "ref": "snapshot/2024-08-01",
+        "repo": "rust-overlay",
+        "type": "github"
       }
     }
   },

flake.nix

@@ -2,29 +2,28 @@
   description = "Bare-metal Rust on Zynq-7000";
 
   inputs.nixpkgs.url = github:NixOS/nixpkgs/nixos-24.05;
-  inputs.mozilla-overlay = { url = github:mozilla/nixpkgs-mozilla; flake = false; };
+  inputs.rust-overlay = {
+    url = "github:oxalica/rust-overlay?ref=snapshot/2024-08-01";
+    inputs.nixpkgs.follows = "nixpkgs";
+  };
 
-  outputs = { self, nixpkgs, mozilla-overlay }:
+  outputs = { self, nixpkgs, rust-overlay }:
     let
-      pkgs = import nixpkgs { system = "x86_64-linux"; overlays = [ (import mozilla-overlay) crosspkgs-overlay ]; };
+      pkgs = import nixpkgs { system = "x86_64-linux"; overlays = [ (import rust-overlay) crosspkgs-overlay ]; };
       
-      rustManifest = pkgs.fetchurl {
-        url = "https://static.rust-lang.org/dist/2021-01-29/channel-rust-nightly.toml";
-        sha256 = "sha256-EZKgw89AH4vxaJpUHmIMzMW/80wAFQlfcxRoBD9nz0c=";
-      };
-      rustTargets = [];
-      rustChannelOfTargets = _channel: _date: targets:
-        (pkgs.lib.rustLib.fromManifestFile rustManifest {
-          inherit (pkgs) stdenv lib fetchurl patchelf;
-          }).rust.override {
-          inherit targets;
+      rust = pkgs.rust-bin.nightly."2021-01-28".default.override {
         extensions = [ "rust-src" ];
+        targets = [ ];
+      };
+      rustPlatform = pkgs.makeRustPlatform {
+        rustc = rust // {
+          # https://github.com/oxalica/rust-overlay/commit/c48c2d76b68dd9ede0815fec53479375c61af857
+          targetPlatforms = pkgs.lib.platforms.all;
+          tier1TargetPlatforms = pkgs.lib.platforms.all;
+          badTargetPlatforms = [ ];
         };
-      rust = rustChannelOfTargets "nightly" null rustTargets;
-      rustPlatform = pkgs.recurseIntoAttrs (pkgs.makeRustPlatform {
-        rustc = rust;
         cargo = rust;
-      });
+      };
 
       # https://doc.rust-lang.org/rustc/linker-plugin-lto.html#toolchain-compatibility
       llvmPackages_11 = pkgs.recurseIntoAttrs (pkgs.callPackage (import ./llvm/11) ({