make -C docs/ linkcheck
make: Entering directory '/tmp/cirrus-ci-build/docs'
Traceback (most recent call last):
  File "/usr/local/bin/sphinx-build", line 8, in <module>
    sys.exit(main())
             ^^^^^^
  File "/usr/local/lib/python3.12/site-packages/sphinx/cmd/build.py", line 326, in main
    locale.setlocale(locale.LC_ALL, '')
  File "/usr/local/lib/python3.12/locale.py", line 615, in setlocale
    return _setlocale(category, locale)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
locale.Error: unsupported locale setting
make: *** [Makefile:19: linkcheck] Error 1
make: Leaving directory '/tmp/cirrus-ci-build/docs'

Exit status: 2