Workaround the broken symbols in libcxx on darwin.

We use a specific patched commit in nixpkgs until the permanent fix is merged.

Makefile

@@ -1,5 +1,2 @@
-build-darwin: nix/base-system/*
-	darwin-rebuild --flake ./nix/base-system build
-
-qpply-darwin: nix/base-system/*
-	darwin-rebuild --flake ./nix/base-system switch
+%-darwin:
+	darwin-rebuild --flake ./nix/base-system $*

nix/base-system/flake.lock

@@ -555,6 +555,22 @@
         "type": "github"
       }
     },
+    "patchedLibcxx": {
+      "locked": {
+        "lastModified": 1705990968,
+        "narHash": "sha256-MYonu7rb4/U++uQtORQqIMc3DX6M1PI1GETAt2br5Vo=",
+        "owner": "nixos",
+        "repo": "nixpkgs",
+        "rev": "1c4b0767f4ef0d277c7352eae00337c0a379b69d",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nixos",
+        "repo": "nixpkgs",
+        "rev": "1c4b0767f4ef0d277c7352eae00337c0a379b69d",
+        "type": "github"
+      }
+    },
     "root": {
       "inputs": {
         "agenix-flake": "agenix-flake",
@@ -567,6 +583,7 @@
         "nixpkgs": "nixpkgs_5",
         "nixpkgs-darwin": "nixpkgs-darwin",
         "nurl-flake": "nurl-flake",
+        "patchedLibcxx": "patchedLibcxx",
         "roslyn-lsp": "roslyn-lsp",
         "runwhen-flake": "runwhen-flake",
         "rust-overlay-flake": "rust-overlay-flake",

nix/base-system/flake.nix

@@ -3,6 +3,7 @@
     # Default to sane nixpkgs versions
     nixpkgs.url = "github:nixos/nixpkgs/23.11";
     unstable.url = "nixpkgs";
+    patchedLibcxx.url = "github:nixos/nixpkgs?rev=1c4b0767f4ef0d277c7352eae00337c0a379b69d";
     nixpkgs-darwin.url = "github:nixos/nixpkgs/nixpkgs-23.11-darwin";
     darwin = {
       url = "github:lnl7/nix-darwin";
@@ -57,6 +58,7 @@
     treesitter-context,
     roslyn-lsp,
     unstable,
+    patchedLibcxx,
     ... # We don't use the self or nixpkgs args here so we just glob it.
   }: 
   rec {
@@ -131,6 +133,7 @@ EOF";
                 vimagit
                 hoon-vim
                 nvim-treesitter
+                lean-nvim
                 roslyn-nvim
                 nvim-treesitter-context
                 nvim-treesitter-textobjects
@@ -198,6 +201,7 @@ EOF";
       age = agenix-flake.packages."${system}".default;
       nurl = nurl-flake.packages."${system}".default;
       unstablePkgs = import unstable { inherit system; };
+      patchedLibcxxPkgs = import patchedLibcxx { inherit system; };
     in { config, pkgs, ... }: let
         d2-lang = pkgs.callPackage ./d2.nix {};
 	in {
@@ -237,7 +241,8 @@ EOF";
         environment.systemPackages = (with pkgs; [
             # TODO(jwall): This appears to be broken due to: https://github.com/NixOS/nixpkgs/issues/166205
             # Should be fixed by: https://github.com/NixOS/nixpkgs/pull/282624
-            #unstablePkgs.isabelle
+            patchedLibcxxPkgs.isabelle
+            patchedLibcxxPkgs.lean4
             terraform # TODO(jeremy): Replace with opentofu when that is an option.
             consul
             consul-template