fuzz: fix Makefile default PYTHON_CONFIG_FLAGS to be modern
This is actually what we already do on oss-fuzz, so it's more correct as tests
go.
Differential Revision: https://phab.mercurial-scm.org/D9790
[tool.black]
line-length = 80
exclude = '''
build/
| wheelhouse/
| dist/
| packages/
| \.hg/
| \.mypy_cache/
| \.venv/
| mercurial/thirdparty/
'''
skip-string-normalization = true
quiet = true