Signed-off-by: David Wood <david@davidtw.co>

Fixes rust-lang#121381

…=joshtriplett

os::net: expanding TcpStreamExt for Linux with `tcp_deferaccept`.

allows for socket to process only when there is data to process, the option sets a number of seconds until the data is ready.

coverage: Remove `pending_dups` from the span refiner

When extracting coverage spans from a function's MIR, we need to decide how to handle spans that are associated with more than one node (BCB) in the coverage control flow graph.

The existing code for managing those duplicate spans is very subtle and difficult to modify. But by eagerly deduplicating those extracted spans in a much simpler way, we can remove a massive chunk of complexity from the span refiner.

There is a tradeoff here, in that we no longer try to retain *all* nondominating BCBs that have the same span, only the last one in the (semi-arbitrary) dominance ordering. But in practice, this produces very little difference in our coverage tests, and the simplification is so significant that I think it's worthwhile.

`@rustbot` label +A-code-coverage

… r=wesleywiser

triagebot: add queue notifications

This seems like it could be useful.

r? `@wesleywiser`

…-errors

never patterns: Fix liveness analysis in the presence of never patterns

There's a bunch of code that only looks at the first alternative of an or-pattern, under the assumption that all alternatives have the same set of bindings. This is true except for never pattern alternatives  (e.g. `Ok(x) | Err(!)`), so we skip these. I expect there's other code with this problem, I'll have to check that later.

I don't have tests for this yet because mir lowering causes other issues; I'll have some in the next PR.

r? `@compiler-errors`

…trochenkov

Solaris linker does not support --strip-debug

Fixes rust-lang#121381

Add a couple tests

Fixes rust-lang#119857
Fixes rust-lang#115497