std: Fix build for NuttX targets

[thaliaarchi]

Fix std build for all NuttX targets. It is the single largest set of failures on https://does-it-build.noratrieb.dev/. Although, ESP-IDF also requires these same gates, there are other issues for those targets.

This can verified be running x check library/std --target= for all NuttX targets.

cc @no1wudi

[rustbot]

r? @Mark-Simulacrum

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[no1wudi]

LGTM, thanks!

BTW, the missing SIGABRT will be fixed by rust-lang/libc#4353

[thaliaarchi]

Nice! When I saw the missing SIGABRT via x check library, I decided to scale back my ambition and only fix x check library/std for now, haha.

[bors]

☔ The latest upstream changes (presumably #139401) made this pull request unmergeable. Please resolve the merge conflicts.

[thaliaarchi]

@Mark-Simulacrum Hey, friendly two-week ping.

I've checked it again locally, rebased onto master, and it's still necessary for building NuttX.

[Mark-Simulacrum]

@bors r+

[bors]

📌 Commit 0acac2c has been approved by Mark-Simulacrum

It is now in the queue for this repository.

[bors]

⌛ Testing commit 0acac2c with merge 4b79f3c...

[rust-log-analyzer]

The job armhf-gnu failed! Check out the build log: (web) (plain)

Click to see the possible cause of the failure (guessed by this bot)

[bors]

💔 Test failed - checks-actions

[thaliaarchi]

This PR has been quite unlucky with CI 😅. The failures in the first two rollups were caused by other PRs. The third rollup and when tested alone look spurious. The only kind of failure we could possibly get for this is a compile error, but since the platforms changed here aren't tested in CI, it effectively changes nothing.

Can we try again in the queue?

Rollup #139717 (comment) (caused by #137494)

error: unused variable: `open_devnull`
  --> library/std/src/sys/pal/unix/mod.rs:65:17
   |
65 |         let mut open_devnull = || {
   |                 ^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_open_devnull`

error: variable does not need to be mutable
  --> library/std/src/sys/pal/unix/mod.rs:65:13
   |
65 |         let mut open_devnull = || {
   |             ----^^^^^^^^^^^^

Rollup #139723 (comment) (caused by #138881)

---- [codegen] tests/codegen/array-cmp.rs stderr ----
error: verification with 'FileCheck' failed
/checkout/tests/codegen/array-cmp.rs:43:12: error: CHECK: expected string not found in input
 // CHECK: %[[PA01:.+]] = getelementptr{{.+}}i8, ptr %a, i64 2

Rollup #139728 (comment)

curl: (6) Could not resolve host: ci-mirrors.rust-lang.org
Process completed with exit code 6.

Alone #138972 (comment)

---- [ui] tests/ui/abi/extern/extern-call-deep.rs stderr ----
thread 'main' panicked at src/tools/remote-test-client/src/main.rs:309:9:
client.read_exact(&mut header) failed with Connection reset by peer (os error 104)

[jieyouxu]

2025-04-13T03:57:03.7507822Z thread 'main' panicked at src/tools/remote-test-client/src/main.rs:309:9:
2025-04-13T03:57:03.7509260Z client.read_exact(&mut header) failed with Connection reset by peer (os error 104)
2025-04-13T03:57:03.7510193Z note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

@bors retry