[PATCH] doc: add support for adding configure options as Sphinx tags

[David Bremner]

Jani Nikula <jani at nikula.org> writes:

> Add the configure options specified in $(TAGS) that equal 1 as tags on
> the Sphinx command line using the -t option. The tags may be used to
> conditionally include documentation using the Sphinx "only" directive
> [1].
>
> As an example, indicate in the documentation whether the Xapian field
> processor is likely to be available (assuming the notmuch binary was
> built in the same environment as the documentation).
>
> [1] http://www.sphinx-doc.org/en/stable/markup/misc.html#including-content-based-on-tags
>
> ---
>
> This is something I wrote two years ago, ISTR David asking about
> something like this on IRC, but I've already forgotten what it was
> about...

The urgent-ish issue is getting the docs building without
emacs. Hopefully similar technology can comment out the emacs docs from
the sphinx index page?

d