[Backport] Fix linking of relative modules and external preamble #54

	---
	name: Python Black Formatting

	on:
	- push
	- pull_request
	- fork

	jobs:
	black:
	name: Black
	runs-on: ubuntu-latest

	steps:
	- uses: actions/checkout@v3

	- name: Set up Python
	uses: actions/setup-python@v4
	with:
	python-version: '3.10'

	- name: Install
	run: \|
	python -m pip install --upgrade pip
	pip install black==23.3.0

	- name: Run Black
	run: \|
	black --check --diff setup.py run.py ctypesgen/ \
	--exclude='${{ env.EXCLUDE }}'
	env:
	EXCLUDE: ".*tab.py\|ctypesgen/parser/cgrammar.py\|\
	ctypesgen/parser/lex.py\|ctypesgen/parser/yacc.py"

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