Comment # 51 on bug 968405 from Egbert Eich

(In reply to Michael Schr�der from comment #45)
> Comment#42 and #43: Your macro change will also only take effect when the
> corresponding packages are released again, as the macros are already
> expanded in the binary packages. So I don't see any difference.

Of course. For any package released after the broken macros was released it is
too late.
The difference is: when you change the semantics, you will have to notify each
maintainer of a consumer of the macro of the change and make sure any possible
update is properly serialized with the update to systemd-rpm-macros.

Of course it would be possible to have both the new (macro option driven) and
old deprecated env variable driven semantics around in parallel for a while.