install: validate -o, -g, and -f values when run with -U #2158

	name: Style Checker

	# Runs my simple style(9) checker on pull requests.

	on:
	pull_request: # maybe pull_request_target
	branches: [ main ]
	types: [ opened, reopened, edited, synchronize ]
	paths: [ '.S', '.c', '.cc', '.cpp', '.h', '.hh', '**.hpp' ]

	permissions:
	contents: read

	jobs:
	build:
	name: Style Checker
	runs-on: ubuntu-latest
	steps:
	# Unfortunately there doesn't seem to be a way to
	# do this without an extra step.
	- name: Get depth
	run: \|
	echo "DEPTH=$(( ${{ github.event.pull_request.commits }} + 1 ))" >> $GITHUB_ENV
	- name: checkout
	uses: actions/checkout@v4
	with:
	fetch-depth: ${{ env.DEPTH }}
	ref: ${{ github.event.pull_request.head.sha }}
	- name: Install packages
	run: \|
	sudo apt-get update --quiet \|\| true
	sudo apt-get -yq --no-install-suggests --no-install-recommends install perl
	- name: Run checker
	run: \|
	sha=$(git rev-parse HEAD~${{ github.event.pull_request.commits }})
	tools/build/checkstyle9.pl --github ${sha}..${{ github.event.pull_request.head.sha }}

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