What's the line length limit in the Emacs codebase?

[Philipp Stephani]

Hi,

There seem to be conflicting settings for the line length limit in the
Emacs codebase: .dir-locals.el sets fill-column to 70, but large areas
of the source code (including comments) seem to use 80. Can we pick
one value and use it consistently (for new/changed code)?

Thanks,
Philipp