I'm afraid I forgot to include this change for the CD and the next WD (N4917), which now only has the __cpp_lib_format macro, without the splitting discussed above. However, I believe the feature test macros are overall editorial in nature, so I would be happy to make the change immediately now, and nobody needs to file NB comments about it? I gather also that there's been new discussion, so could you kindly confirm whether the plan from my previous mail is still acceptable or whether we'd like a different set of macros now?
JW> This is a normative change, and shouldn't be changed in the draft until the Tentatively Ready status changes to Resolved at the next plenary.
This is what Mr. Wakely had to say about adding flat_set macro which has the backing of an LWG issue. So if we’re not going to treat the addition of the macro as normative then we should file an LWG issue for format and we will fix it in the next draft. We don’t need NB comments to fix issues in the CD.