Defaulting to user installation because normal site-packages is not writeable
Processing /tmp/pyerfa-2.0.0.1
  Installing build dependencies ... done
  Getting requirements to build wheel ... error
  ERROR: Command errored out with exit status 1:
   command: /usr/bin/python /usr/lib/python3.9/site-packages/pep517/in_process/_in_process.py get_requires_for_build_wheel /tmp/tmpzh5ys6sk
       cwd: /tmp/pip-req-build-9w07y1r1
  Complete output (18 lines):
  Traceback (most recent call last):
    File "/usr/lib/python3.9/site-packages/pep517/in_process/_in_process.py", line 349, in <module>
      main()
    File "/usr/lib/python3.9/site-packages/pep517/in_process/_in_process.py", line 331, in main
      json_out['return_val'] = hook(**hook_input['kwargs'])
    File "/usr/lib/python3.9/site-packages/pep517/in_process/_in_process.py", line 117, in get_requires_for_build_wheel
      return hook(config_settings)
    File "/tmp/pip-build-env-ahol4mwv/overlay/lib/python3.9/site-packages/setuptools/build_meta.py", line 162, in get_requires_for_build_wheel
      return self._get_build_requires(
    File "/tmp/pip-build-env-ahol4mwv/overlay/lib/python3.9/site-packages/setuptools/build_meta.py", line 143, in _get_build_requires
      self.run_setup()
    File "/tmp/pip-build-env-ahol4mwv/overlay/lib/python3.9/site-packages/setuptools/build_meta.py", line 158, in run_setup
      exec(compile(code, __file__, 'exec'), locals())
    File "setup.py", line 165, in <module>
      setuptools.setup(use_scm_version=use_scm_version, ext_modules=get_extensions())
    File "setup.py", line 72, in get_extensions
      raise RuntimeError(
  RuntimeError: Missing "liberfa" source files, unable to generate "erfa/ufunc.c" and "erfa/core.py". Please check your source tree. Maybe "git submodule update" could help.
  ----------------------------------------
WARNING: Discarding file:///tmp/pyerfa-2.0.0.1. Command errored out with exit status 1: /usr/bin/python /usr/lib/python3.9/site-packages/pep517/in_process/_in_process.py get_requires_for_build_wheel /tmp/tmpzh5ys6sk Check the logs for full command output.
ERROR: Command errored out with exit status 1: /usr/bin/python /usr/lib/python3.9/site-packages/pep517/in_process/_in_process.py get_requires_for_build_wheel /tmp/tmpzh5ys6sk Check the logs for full command output.