[coroutine.handle.resumption] "an instance of std::thread" is not an execution agent

[jwakely]

The wording (pre-Cologne) says:

has implementation-defined behavior unless each execution agent is either an instance of std::thread or the thread that executes main.

This is a category error. An instance of std::thread is an object with class type, not an execution agent.

I think it wants to say "unless each execution agent is a thread started by std::thread, or the thread that executes main."

[jwakely]

PR #3072 touches this wording, so fixing it should wait for that to land.

[jensmaurer]

#3072 has landed.

[jensmaurer]

Editorial meeting: Go with Jonathan's suggestion. Retain "either ... or".

Existing wording is actually wrong, so have SG1 / LWG oversight here. "started by" is probably right (given detached threads), but that's a normative change.