Fix compile errors for non-Linux targets

[xtqqczze]

Contributes to #11019

to avoid compile errors on non-Linux platforms, failing pre-commit check

[github-actions]

GNU testsuite comparison:

Skip an intermittent issue tests/date/date-locale-hour (fails in this run but passes in the 'main' branch)
Skip an intermittent issue tests/misc/io-errors (fails in this run but passes in the 'main' branch)
Skipping an intermittent issue tests/cut/bounded-memory (passes in this run but fails in the 'main' branch)
Skipping an intermittent issue tests/tail/retry (passes in this run but fails in the 'main' branch)
Note: The gnu test tests/cut/cut-huge-range is now being skipped but was previously passing.
Skip an intermittent issue tests/pr/bounded-memory (was skipped on 'main', now failing)

[codspeed-hq]

Merging this PR will improve performance by 13.71%

⚡ 2 improved benchmarks
✅ 315 untouched benchmarks
⏩ 46 skipped benchmarks¹

Performance Changes

	Mode	Benchmark	BASE	HEAD	Efficiency
⚡	Memory	cp_recursive_deep_tree[(120, 4)]	699.2 KB	562.5 KB	+24.31%
⚡	Simulation	ls_recursive_balanced_tree[(6, 4, 15)]	50.9 ms	48.9 ms	+4.01%

Tip

Curious why this is faster? Comment @codspeedbot explain why this is faster on this PR, or directly use the CodSpeed MCP with your agent.

---

_{Comparing xtqqczze:not-supported-target (f203f6c) with main (d09f351)}

Footnotes

1. 46 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. ↩

[oech3]

I don't like this solution. This is already covered by feature.

[xtqqczze]

I would like to get cargo clippy --workspace --all-targets --all-features working.

[oech3]

It does not making a sense to clippy unsupported part.

[oech3]

At least, I think distributor does not want to distribute stubs if Mafefile included a bug someday. compile_error! is better behavior for distributors.

[oech3]

You should ask upstream to auto-skip clippy when compile_error! appear.
Stub should not be distributed accidentaly anyway.

[oech3]

rust-lang/cargo#1197

[xtqqczze]

We already use supports stubs for chcon and runcon: #8795

[oech3]

People on MSYS2 could try to replace system binary with main's binary, or replace cygwin binary with windows binary if cygpath is not an issue. In the case, people can incorrectly override proper nohup.exe by stub nohup.exe and break the system. (*con are accidentally exception since MSYS does not have them. But we should not have)

[xtqqczze]

I guess we could avoid stubs with:

#![cfg_attr(not(unix), no_main)]
#![cfg(unix)]
uucore::bin!(uu_nohup);

Then we get a linker error, but at least no compile errors.

[oech3]

How about just removing compile_error!?

[xtqqczze]

The crate fails compile for non-Unix, so it seems the only options are to use a stub, linker error, or compile error.

[oech3]

I passed cargo check -p uu_true with #![no_main] only. So it looks best solution.

[oech3]

I'll investigate what I can do for bin! macro itself.

[oech3]

not(clippy)

[xtqqczze]

not(clippy)

Doesn't help for compile errors, e.g. with cargo check.

[oech3]

Linker error should happen also for multicall-call binary.

[xtqqczze]

Linker error should happen also for multicall-call binary.

How can I test this?

[oech3]

cargo check --no-default-features --features nohup