LWG4521 Improve [atomics.order] p10 to have a consistent way with [intro.races]

[jwakely]

https://cplusplus.github.io/LWG/issue4521

This one needs SG1 consideration too.

[rarutyun]

SG1 looked at this in Croydon, March 2026.

Poll: Approve option B to resolve LWG4521 and send it back to LWG

Outcome: No objection to unanimous consent

[Dani-Hub]

Thanks, applied the discussion result and adjusted P/R accordingly