uutests: gate by target support

[xtqqczze]

RUSTC_BOOTSTRAP=1 cargo clippy -q -Zbuild-std=std,panic_abort -p uutests --all-features --target=powerpc64-ibm-aix --target=x86_64-linux-android --target=x86_64-pc-cygwin --target=aarch64-apple-darwin --target=x86_64-unknown-freebsd --target=x86_64-unknown-haiku --target=x86_64-unknown-hermit --target=x86_64-unknown-hurd-gnu --target=aarch64-unknown-illumos --target=x86_64-unknown-linux-gnu --target=i686-unknown-netbsd --target=x86_64-unknown-openbsd --target=x86_64-unknown-redox --target=x86_64-pc-solaris --target=wasm32-wasip1 --target=x86_64-pc-windows-gnu

Closes #14935.

[github-actions]

Binary size comparison:

Individual binary size comparison VS main (threshold: >=5% AND >=4 KB).

Total size of compared binaries: 153.09 MB (+904 KB, +0.58%)

Significant per-binary changes:
  expr     2.76 MB ->    3.65 MB  (+908 KB, +32.11%)

[codspeed]

Merging this PR will degrade performance by 7.88%

⚠️ 124 benchmarks spent significant time in system calls

System calls cannot be consistently instrumented, so they are not included in the measure, which understates the real cost. Please switch to the Walltime instrument to accurately measure system calls.

Measurement and system calls

• du_wide_tree[(5000, 500)]
• du_all_wide_tree[(5000, 500)]
• sort_numeric_utf8_locale
• sort_mixed_utf8_locale
• cksum_default
• dd_copy_64k_blocks
• sort_unique_utf8_locale
• cksum_multiple_files
• cksum_crc32b
• dd_copy_partial
• …and 114 more

ℹ️ 1 benchmark has no flame graph

The flamegraph could not be generated because too much time was spent in runtime internals, making the visualization not useful for performance analysis.

• sort_dictionary_order[500000]

❌ 2 regressed benchmarks
✅ 332 untouched benchmarks
⏩ 137 skipped benchmarks¹

Warning

Please fix the performance issues or acknowledge them on CodSpeed.

Performance Changes

	Mode	Benchmark	BASE	HEAD	Efficiency
❌	Simulation	factor_five_38_bit_primes	1.6 s	1.8 s	-11.2%
❌ ⚠️	Simulation	du_wide_tree[(5000, 500)]	15.3 ms	16 ms	-4.44%

Tip

Investigate this regression by commenting @codspeedbot fix this regression on this PR, or directly use the CodSpeed MCP with your agent.

---

_{Comparing xtqqczze:targets-uutests (6f65a3b) with main (7654e67)}

Footnotes

1. 137 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

[github-actions]

GNU testsuite comparison:

Skip an intermittent issue tests/date/resolution (fails in this run but passes in the 'main' branch)

[sylvestre]

why a new crate? rustix already gives us setrlimit, and we still need rustix process for the other tests

[xtqqczze]

Without the rlimit switch, uutests would fail to build on Redox, blocking progress toward getting Redox CI working. Since this only affects tests, I don't think the additional dependency is a concern.

[sylvestre]

please split the rlimit switch and the target gating into two PRs

[xtqqczze]

I have #14739, but that is blocked on Redox CI.

[sylvestre]

why compile the whole crate to nothing on aix/horizon? what fails there?

[xtqqczze]

nix fails to compile on both:

$ RUSTC_BOOTSTRAP=1 cargo hack clippy -Zbuild-std=std,panic_abort --quiet -p uutests --all-features --lib --target powerpc64-ibm-aix
info: running `cargo clippy -Zbuild-std=std,panic_abort --quiet --all-features --lib --target powerpc64-ibm-aix` on uutests (1/1)
error[E0425]: cannot find type `Pid` in this scope
  --> ~/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/nix-0.31.3/src/pty.rs:38:16
   |
38 |         child: Pid,
   |                ^^^ not found in this scope
   |
help: consider importing this struct
   |
 3 + use crate::unistd::Pid;
   |
$ cargo +nightly hack clippy -Zbuild-std=std,panic_abort --quiet -p uutests --all-features --lib --target armv6k-nintendo-3ds
info: running `cargo clippy -Zbuild-std=std,panic_abort --quiet --all-features --lib --target armv6k-nintendo-3ds` on uutests (1/1)
error[E0432]: unresolved import `self::consts`
  --> /Users/matthew/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/nix-0.31.3/src/errno.rs:19:15
   |
19 | pub use self::consts::*;
   |               ^^^^^^ could not find `consts` in `self`