GNU Make is used by so many people for so many things, and I'm leery of
creating some new facility that ends up being "not really right" for what
people want to do, but that then must be maintained forever going forward.
It seems to me to be an understandable problem where people very much wish to add things that suit them but the project cannot because of the implied support and the fact that they might not turn out to be desirable in the long run but still have to be supported forever.
Perhaps make could do with some sort of plugin mechanism? I know it has the load keyword within makefiles but I'm not sure if functions have access to enough global state to e.g. print out a list of targets. One might want other entry points like "after parsing" or "before reading a makefiule" or "after updating a target" where one's plugin functions might be called. Then you could get a list of updated targets or perform some special action to compress and transmit them without waiting for the build to finish or any number of wonderful possibilities.
One might want to have a way to "add a commandline option" where one might supply a flag to activate the plugin.
Ideally make would end up with some sort of repository for unsupported/unofficial modules/plugins and in the distant future there might be a way to automatically fetch them. This way you could take a decision later about how popular/useful some feature was and decide to include it in the standard release. The available entrypoints and "blessed" global variables or inputs would be an api with version numbering that would ensure one could make changes and know when your plugin needed chaning to accomodate them and when those changes were non-breaking.
I am sure the idea and implications are completely obvious - I'm just trying to suggest that there has to be a way out of the impasse.
Regards,
Timothy N Murphy