Build error on Arch Linux with python-build

On Arch Linux with these make dependencies installed: python-build python-installer python-setuptools python-wheel and running python -m build --wheel --no-isolation (as per https://wiki.archlinux.org/title/Python_package_guidelines#Standards_based_(PEP_517)) leads to the following:

* Getting build dependencies for wheel...
validate_pyproject.api.load_builtin_plugin defines `tool.distutils` schema
validate_pyproject.api.load_builtin_plugin defines `tool.setuptools` schema
No `packages` or `py_modules` configuration, performing automatic discovery.
`flat-layout` detected -- analysing .
discovered packages -- ['mrhlpr', 'mrtest', 'mrhlpr.data']
Traceback (most recent call last):
  File "/usr/lib/python3.12/site-packages/pyproject_hooks/_in_process/_in_process.py", line 373, in <module>
    main()
  File "/usr/lib/python3.12/site-packages/pyproject_hooks/_in_process/_in_process.py", line 357, in main
    json_out["return_val"] = hook(**hook_input["kwargs"])
                             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/site-packages/pyproject_hooks/_in_process/_in_process.py", line 134, in get_requires_for_build_wheel
    return hook(config_settings)
           ^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/site-packages/setuptools/build_meta.py", line 325, in get_requires_for_build_wheel
    return self._get_build_requires(config_settings, requirements=['wheel'])
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/site-packages/setuptools/build_meta.py", line 295, in _get_build_requires
    self.run_setup()
  File "/usr/lib/python3.12/site-packages/setuptools/build_meta.py", line 311, in run_setup
    exec(code, locals())
  File "<string>", line 1, in <module>
  File "/usr/lib/python3.12/site-packages/setuptools/__init__.py", line 103, in setup
    return distutils.core.setup(**attrs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/site-packages/setuptools/_distutils/core.py", line 159, in setup
    dist.parse_config_files()
  File "/usr/lib/python3.12/site-packages/setuptools/dist.py", line 627, in parse_config_files
    pyprojecttoml.apply_configuration(self, filename, ignore_option_errors)
  File "/usr/lib/python3.12/site-packages/setuptools/config/pyprojecttoml.py", line 72, in apply_configuration
    config = read_configuration(filepath, True, ignore_option_errors, dist)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/site-packages/setuptools/config/pyprojecttoml.py", line 137, in read_configuration
    return expand_configuration(asdict, root_dir, ignore_option_errors, dist)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/site-packages/setuptools/config/pyprojecttoml.py", line 162, in expand_configuration
    return _ConfigExpander(config, root_dir, ignore_option_errors, dist).expand()
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/site-packages/setuptools/config/pyprojecttoml.py", line 210, in expand
    self._expand_all_dynamic(dist, package_dir)
  File "/usr/lib/python3.12/site-packages/setuptools/config/pyprojecttoml.py", line 255, in _expand_all_dynamic
    version=self._obtain_version(dist, package_dir),
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/site-packages/setuptools/config/pyprojecttoml.py", line 304, in _obtain_version
    return _expand.version(self._obtain(dist, "version", package_dir))
                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/site-packages/setuptools/config/pyprojecttoml.py", line 293, in _obtain
    return self._expand_directive(
           ^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/site-packages/setuptools/config/pyprojecttoml.py", line 287, in _expand_directive
    return _expand.read_attr(directive["attr"], package_dir, root_dir)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/site-packages/setuptools/config/expand.py", line 188, in read_attr
    _parent_path, path, module_name = _find_module(module_name, package_dir, root_dir)
                                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/site-packages/setuptools/config/expand.py", line 229, in _find_module
    if package_dir:
       ^^^^^^^^^^^
  File "/usr/lib/python3.12/site-packages/setuptools/config/expand.py", line 459, in __len__
    return len(self._target())
               ^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/site-packages/setuptools/config/expand.py", line 452, in _target
    self._value = self._obtain()
                  ^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/site-packages/setuptools/config/expand.py", line 422, in _get_package_dir
    self()
  File "/usr/lib/python3.12/site-packages/setuptools/config/expand.py", line 412, in __call__
    self._dist.set_defaults(name=False)  # Skip name, we can still be parsing
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/site-packages/setuptools/discovery.py", line 353, in __call__
    self._analyse_package_layout(ignore_ext_modules)
  File "/usr/lib/python3.12/site-packages/setuptools/discovery.py", line 387, in _analyse_package_layout
    or self._analyse_flat_layout()
       ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/site-packages/setuptools/discovery.py", line 444, in _analyse_flat_layout
    return self._analyse_flat_packages() or self._analyse_flat_modules()
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/site-packages/setuptools/discovery.py", line 450, in _analyse_flat_packages
    self._ensure_no_accidental_inclusion(top_level, "packages")
  File "/usr/lib/python3.12/site-packages/setuptools/discovery.py", line 480, in _ensure_no_accidental_inclusion
    raise PackageDiscoveryError(cleandoc(msg))
setuptools.errors.PackageDiscoveryError: Multiple top-level packages discovered in a flat-layout: ['mrhlpr', 'mrtest'].

To avoid accidental inclusion of unwanted files or directories,
setuptools will not proceed with this build.

If you are trying to create a single distribution with multiple packages
on purpose, you should not rely on automatic discovery.
Instead, consider the following options:

1. set up custom discovery (`find` directive with `include` or `exclude`)
2. use a `src-layout`
3. explicitly set `py_modules` or `packages` with a list of names

To find more information, look for "package discovery" on setuptools docs.

ERROR Backend subprocess exited when trying to invoke get_requires_for_build_wheel

Perhaps the gpep517 that is used for Alpine packaging works a bit differently?