This is not specific to C, but common to all evolving standards. If you want portable code just drive on the middle of the road. Often this is as easy as codin

This is not specific to C, but common to all evolving standards. If you want portable code just drive on the middle of the road. Often this is as easy as coding to an older standard, like C89 with a few selected features from later standards, and adding some compatibility features / problem detection in the build system. And don't rely on features that are difficult to explain and/or add only questionable value. Just return 0 from main, it's the obvious simple thing to do.