Re: autoconf-mode fontification

[Björn Bidar]

I don't exactly know. First thing I see is that autoconf.el
claims the autoconf-mode.el appears to be for Autoconf M4 sources
while autoconf-mode.el suggests the user to register
it to auto-mode-alist for configure.ac/configure.in

It would be great to clarify that and reduce duplicate work
if possible.
Would it make sense to crosspost this thread to them?

That the autoconf-mode from autoconf-mode.el didn't work for recent
Emacs seems to be because of the way it's activated in the autoconf-mode
function, I don't know exactly why but changing it to use
define-derived-mode fixed the issue for me, it should have used the
function in any case I think.