Severity: minor The "# serial" lines are only considered by aclocal for the system-wide third-party '.m4' files, not for the Automake-provided ones (and even in that case, they are considered only when the '--install' aclocal option is used). So they serve no real purpose in the Automake '.m4' files.
In addition, now that we use git and topic branches, and that we are also writing the Automake-NG fork, the "# serial" lines are becoming more and more unreliable (different version of the same file in different branches can easily end up having the same serial numbers). So I propose we just nuke the "#serial" lines. Any objection? If not, I will proceed in a couple of days, in all of the 'maint', 'master' and 'ng/master' branches. Regards, Stefano