Pin the clang version to 11 for lean beause reasons.

nix/base-system/flake.nix

@@ -213,7 +213,11 @@ EOF";
       config = {
        
         nixpkgs.overlays = [
-         rust-overlay
+          (final: prev: {
+            # This is needed because the ccache used by lean4Pkg is broken
+            ccache = prev.ccache.override { doCheck = false; };
+          })
+          rust-overlay
         ];
 
         # TODO(jwall): This is needed for terraform
@@ -241,7 +245,9 @@ EOF";
             # 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
             #isabelle
-            lean4
+            # 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
+            (lean4.override { stdenv = stdenv.override { allowedRequisites = null; cc = llvmPackages_11.clang; }; })
             terraform # TODO(jeremy): Replace with opentofu when that is an option.
             consul
             consul-template
@@ -294,8 +300,9 @@ EOF";
             # TODO(jwall): I include these initially for nvim telescope
             ripgrep
             fd
-            lldb
+            lldb_11
-            llvmPackages.bintools-unwrapped
+            # TODO(jwall): For now it appears that a bunch of things around linking are broken on darwin so we are going to use clang11
+            llvmPackages_11.libcxxClang
             # TODO add sonic-pi here if it supports the arch
         ])
         ++ (with pkgs.ocamlPackages; [