[...] At this point I'm inclined to give up and revert 3a60c8ff8. It's not clear that we can really make the warning situation better, as opposed to just moving the warnings from one platform to another.
Indeed, there are hundreds of warnings around "pg_printf_attribute_m" added with gcc 7.3.0 on by ubuntu 18.04 laptop, thanks to 3a60c8ff.
A revert would help. -- Fabien.
