diff --git a/flake.nix b/flake.nix
index 5677d23..ecacc67 100644
--- a/flake.nix
+++ b/flake.nix
@@ -15,8 +15,6 @@
         config.allowUnfree = true;
       };
 
-      lib = pkgs.lib;
-
       packages = rec {
         proj = pkgs.python3Packages.callPackage ./pkgs/proj { 
           inherit pytest-skip-slow;
diff --git a/pkgs/doctest/default.nix b/pkgs/doctest/default.nix
index 53447e8..9540742 100644
--- a/pkgs/doctest/default.nix
+++ b/pkgs/doctest/default.nix
@@ -1,4 +1,5 @@
 { pkgs
+, fetchpatch
 }:
 
 pkgs.doctest.overrideAttrs ( old: rec {
@@ -11,5 +12,13 @@ pkgs.doctest.overrideAttrs ( old: rec {
   };
   patches = [
     ./doctest-template-test.patch
+
+    # Fix the build with Clang.
+    (fetchpatch {
+      name = "doctest-disable-warnings.patch";
+      url = "https://github.com/doctest/doctest/commit/c8d9ed2398d45aa5425d913bd930f580560df30d.patch";
+      excludes = [ ".github/workflows/main.yml" ];
+      hash = "sha256-kOBy0om6MPM2vLXZjNLXiezZqVgNr/viBI7mXrOZts8=";
+    })
   ];
 })
diff --git a/pkgs/ff-clang-format.nix b/pkgs/ff-clang-format.nix
index 4807b8f..130558b 100644
--- a/pkgs/ff-clang-format.nix
+++ b/pkgs/ff-clang-format.nix
@@ -1,4 +1,5 @@
-{ stdenv
+{ pkgs
+, stdenv
 , lib
 , autoPatchelfHook
 , fetchurl
@@ -10,12 +11,21 @@ stdenv.mkDerivation rec {
 
   system = "x86_64-linux";
 
-  src = fetchurl {
-    url = "https://github.com/muttleyxd/clang-tools-static-binaries/releases/download/${version}/clang-format-16_linux-amd64";
-    hash = "sha256-5eTzOVcmuvSNGr2lyQrBO2Rs0vOed5k7ICPw0IPq4sE=";
-  };
+  src = let
+    blobs = {
+      x86_64-linux = {
+        url = "https://github.com/muttleyxd/clang-tools-static-binaries/releases/download/${version}/clang-format-16_linux-amd64";
+        hash = "sha256-5eTzOVcmuvSNGr2lyQrBO2Rs0vOed5k7ICPw0IPq4sE=";
+      };
+      x86_64-darwin = {
+        url = "https://github.com/muttleyxd/clang-tools-static-binaries/releases/download/${version}/clang-format-16_macosx-amd64";
+        hash = "sha256-I9F/mn3I+ZAq2aDw0Mc9Imo+AJMwbzsjalqBSo/7DL4=";
+      };
+    };
+  in
+    fetchurl blobs.${pkgs.system};
 
-  nativeBuildInputs = [
+  nativeBuildInputs = lib.optionals stdenv.isLinux [
     autoPatchelfHook
   ];
 
@@ -29,6 +39,6 @@ stdenv.mkDerivation rec {
 
   meta = with lib; {
     homepage = "https://github.com/muttleyxd/clang-tools-static-binaries";
-    platforms = platforms.linux;
+    platforms = platforms.linux ++ platforms.darwin;
   };
 }
diff --git a/pkgs/proj/default.nix b/pkgs/proj/default.nix
index e319c81..ccd71d5 100644
--- a/pkgs/proj/default.nix
+++ b/pkgs/proj/default.nix
@@ -1,4 +1,5 @@
-{ buildPythonApplication
+{ pkgs
+, buildPythonApplication
 , pytestCheckHook
 , typing-extensions
 , enlighten
@@ -34,17 +35,21 @@
 }:
 
 let
+  lib = pkgs.lib;
+  stdenv = pkgs.stdenv;
+
   bins = [
-    valgrind
-    kcachegrind
     ff-clang-format
-    bencher-cli
-    hotspot
-    perf
     ccache
     compdb
     cmake
     lcov
+  ] ++ lib.optionals stdenv.isLinux [
+    bencher-cli
+    hotspot
+    valgrind
+    kcachegrind
+    perf
   ];
 in 
 buildPythonApplication {