Building documentation on Windows

[Martin Bonner]

I am trying to build documentation on Windows with `make htmldocs`.
In additions to the modules I have installed for building tools (such
as  fit-check-sign), I have installed
    pacman -S mingw-w64-x86_64-python-sphinx
    pacman -S mingw-w64-x86_64-fontconfig
    pacman -S mingw-w64-x86_64-python-sphinx_rtd_theme
in response to errors.

My latest error is:
Extension error:
Could not import extension kfigure (exception: No module named 'six')
make[1]: *** [doc/Makefile:68: htmldocs] Error 2
make: *** [Makefile:2412: htmldocs] Error 2

so my natural instinct was `pip install six` - but this failed with
Requirement already satisfied: six in /usr/lib/python3.10/site-packages (1.16.0)

Does anyone have any suggestion how to fix this?

Martin