Q:

Printable PDF output with links as footnotes

I'm using sphinx to generate the documentation of a python project and I'm making heavy use of  external links. I'd like to build html and latexpdf outputs with these as clickable links (which is the default), but also a PDF version that will be printed, with these links showing up in footnotes.
In short: is there a way to write external links in a .rst file like this:
Ask a question on `my favorite Q&A website <http://stackoverflow.com/>`_.

and have a special output that will interpret this as if it was a footnote written like this:
Ask a question on my favorite Q&A website [#SO]_.

.. [#SO] http://stackoverflow.com/

while keeping the normal behavior (clickable link without a footnote) in other outputs?

A:

Jongware's comment made me look at parts of the sphinx documentation I didn't see, and I realized there actually is a configuration variable that does what I want:
latex_show_urls = 'footnote'

As I wanted to be able to generate the usual pdf and the one with the footnotes without changing the conf.py file, I left the default value and added the following rule to the sphinx's Makefile:
.PHONY: printpdf
printpdf: SPHINXOPTS+=-Dlatex_show_urls=footnote
printpdf: latexpdf

This rule calls the regular latexpdf rule, adding -Dlatex_show_urls=footnote to the options given to sphinx-build.
With this, we can generate the PDF to be printed (with footnotes) with:
make printpdf

And if we want a regular PDF, without the potentially numerous and (here) useless footnotes, the regular rule still does it:
make latexpdf

