As @tomyun mentioned in #3827, macOS does not have the `ar' flag D, so linking with our default flags crD fails.
Can anyone with macOS experience recommend a good set of ar flags?
@ecraven since none of us understood the original commit due to ar flags being absolutely impossible to Google, or to understand once you have found something, can you tell us what ar flags are for? And what D was supposed to do?
Just thinking that if we didn't need them previously, can we just remove them again?
If we do not set ARFLAGS, they are cru by default with autotools. ar complains while linking with a warning. The intention of the fix was to get rid of that warning.
I think the best way forward would be to have different ARFLAGS on linux and macOS (crD for linux, cru for macOS). I'll start a PR later, but I cannot test on macOS :-/
Separate configs would be best I think then. From reading the feedback @tomyun gave it looks like they just need leaving blank on OSX.