treewide: remove unused clang from build closure (#360711)

pkgs/by-name/he/helvum/package.nix

@@ -1,6 +1,5 @@
 { lib
 , cargo
-, clang
 , desktop-file-utils
 , fetchFromGitLab
 , glib
@@ -35,7 +34,6 @@ stdenv.mkDerivation rec {
   };
 
   nativeBuildInputs = [
-    clang
     meson
     ninja
     pkg-config

pkgs/by-name/ni/niri/package.nix

@@ -1,6 +1,5 @@
 {
   lib,
-  clang,
   dbus,
   eudev,
   fetchFromGitHub,
@@ -51,7 +50,6 @@ rustPlatform.buildRustPackage rec {
   strictDeps = true;
 
   nativeBuildInputs = [
-    clang
     pkg-config
     rustPlatform.bindgenHook
   ];

pkgs/by-name/xe/xen-guest-agent/package.nix

@@ -2,7 +2,6 @@
   lib,
   fetchFromGitLab,
   rustPlatform,
-  llvmPackages,
   pkg-config,
   xen,
 }:
@@ -21,7 +20,6 @@ rustPlatform.buildRustPackage rec {
 
   nativeBuildInputs = [
     rustPlatform.bindgenHook
-    llvmPackages.clang
     pkg-config
   ];