clang-tidy.yml: updated to Clang 21 (#421) #20

	# Syntax reference https://help.github.com/en/actions/reference/workflow-syntax-for-github-actions
	# Environment reference https://help.github.com/en/actions/reference/virtual-environments-for-github-hosted-runners
	name: clang-tidy

	on: [push, pull_request]

	permissions:
	contents: read

	jobs:
	build:

	runs-on: ubuntu-24.04

	steps:
	- uses: actions/checkout@v4
	with:
	persist-credentials: false

	# the man-db trigger causes package installations to stall for several minutes at times. so just drop the package.
	# see https://github.com/actions/runner/issues/4030
	- name: Remove man-db package
	run: \|
	sudo apt-get update
	sudo apt-get remove man-db

	- name: Install missing software
	run: \|
	sudo apt-get update
	sudo apt-get install -y cmake make

	- name: Install clang
	run: \|
	wget https://apt.llvm.org/llvm.sh
	chmod +x llvm.sh
	sudo ./llvm.sh 21
	sudo apt-get install clang-tidy-21

	- name: Verify clang-tidy configuration
	run: \|
	clang-tidy-21 --verify-config

	- name: Prepare CMake
	run: \|
	cmake -S . -B cmake.output -Werror=dev --warn-uninitialized -DCMAKE_COMPILE_WARNING_AS_ERROR=On -DCMAKE_EXPORT_COMPILE_COMMANDS=ON
	env:
	CXX: clang-21

	- name: Clang-Tidy
	run: \|
	run-clang-tidy-21 -q -j $(nproc) -p=cmake.output

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