python3Packages.hawkmoth: fix broken state with llvm 21 by using 20

Hawkmoth is broken with LLVM 21 release. This is already reported, but
there is no stable fix on the Hawkmoth's size, yet. Thus this changes
the used LLVM version in Hawkmoth to 20.

https://github.com/jnikula/hawkmoth/pull/291

pkgs/development/python-modules/hawkmoth/default.nix

@@ -3,13 +3,18 @@
   buildPythonPackage,
   fetchFromGitHub,
   hatchling,
+  llvmPackages_20,
   libclang,
   sphinx,
-  clang,
   pytestCheckHook,
   strictyaml,
 }:
+let
+  libclang_20 = libclang.override {
+    llvmPackages = llvmPackages_20;
+  };
 
+in
 buildPythonPackage rec {
   pname = "hawkmoth";
   version = "0.21.0";
@@ -25,13 +30,13 @@ buildPythonPackage rec {
   build-system = [ hatchling ];
 
   dependencies = [
-    libclang
+    libclang_20
     sphinx
   ];
-  propagatedBuildInputs = [ clang ];
+  propagatedBuildInputs = [ llvmPackages_20.clang ];
 
   nativeCheckInputs = [
-    clang
+    llvmPackages_20.clang
     pytestCheckHook
     strictyaml
   ];