RFC: Don't create local/* in 4.0

3.0 introduced include if exists which we use a lot, for example for the local/ include files. Nevertheless, we still create empty/comment-only local/ files.

All those empty/comment-only files in local/ make it harder than necessary to find files that were actually edited.

I propose to no longer create the local/ dummy files in 4.0. (At least by default - maybe we {c,sh}ould offer a separate make target for those who still want them.)

Known issues: Packagers will need to find a way to avoid that existing modified local/ files get renamed to *.rpmsave and similar. For rpm, using %ghost might be an option to prevent the renaming. (It might also prevent the automatic cleanup, but that's the smaller problem.)

Feedback, comments and opinions welcome.