Use new cargo argument in bootstrap for cfg checking

[Urgau]

This PR use new cargo argument in bootstrap for doing cfg checking.

Follow-up to #97044 and #97214.

r? @Mark-Simulacrum

[Mark-Simulacrum]

@bors r+ rollup=never

[bors]

📌 Commit 71f60b43514cc14abbf18c5336b165742008d7d8 has been approved by Mark-Simulacrum

[bors]

⌛ Testing commit 71f60b43514cc14abbf18c5336b165742008d7d8 with merge 549c79c9bda4ba63fa8e8cb466e9697a98bf739d...

[bors]

💔 Test failed - checks-actions

[Urgau]

@jyn514@Mark-Simulacrum (bootstrap team, idk if there things are already setup or not)

Would any of you know why when at this stage Building rustdoc for stage2 (x86_64-unknown-illumos) only the rustflags are added and not the cargo ones ?

Context: This PR move some args handling from the rustflags var to the cargo var but it as still leave some unstable things in rustflags. If the cargo flags where added they would also cover the rustflags but it seems that only the rustflags are added and not the cargo flags otherwise it wouldn't failed saying that it's missing -Zunstable-options (passed by the cargo flags). Also note that it has worked for many previous steps.

[Urgau]

Hum... It's seems that from the last run that the problem lies in the cargo implementation of check cfg and not in bootstrap as the arg is indeed passed but cargo doesn't create the args for rustc.

I will figure this out and fix it on the cargo side but in the mean time I will just back-up the merging of all the args (as I don't think it's a huge issue that checking of features is not done when cross-compiling).

EDIT: Actually I'm not so sure anymore. I'm not even sure cargo is involved at all. Which would be the reason why it's failing (as the code assume that cargo is used).

[Urgau]

After some more investigation on CI I'm pretty sure that it's not at all a cargo problem (cargo does not seems to be involve at all when the problem occur) but simply bootstrap who use the rustflags without using the cargo arguments, which leads to the error. To fix the problem I just re-added -Zunstable-options to the rustflags.

@rustbot ready

[Mark-Simulacrum]

@bors r+

Seems OK for now.

[bors]

📌 Commit ff33001 has been approved by Mark-Simulacrum

[bors]

⌛ Testing commit ff33001 with merge 3a8e713...

[bors]

☀️ Test successful - checks-actions
Approved by: Mark-Simulacrum
Pushing 3a8e713 to master...

[rust-timer]

Finished benchmarking commit (3a8e713): comparison url.

Instruction count

This benchmark run did not return any relevant results for this metric.

Max RSS (memory usage)

Results

• Primary benchmarks: no relevant changes found
• Secondary benchmarks: 😿 relevant regressions found

	mean1	max	count2
Regressions 😿 (primary)	N/A	N/A	0
Regressions 😿 (secondary)	3.1%	4.2%	3
Improvements 🎉 (primary)	N/A	N/A	0
Improvements 🎉 (secondary)	N/A	N/A	0
All 😿🎉 (primary)	N/A	N/A	0

Cycles

Results

• Primary benchmarks: 😿 relevant regression found
• Secondary benchmarks: no relevant changes found

	mean1	max	count2
Regressions 😿 (primary)	2.3%	2.3%	1
Regressions 😿 (secondary)	N/A	N/A	0
Improvements 🎉 (primary)	N/A	N/A	0
Improvements 🎉 (secondary)	N/A	N/A	0
All 😿🎉 (primary)	2.3%	2.3%	1

If you disagree with this performance assessment, please file an issue in rust-lang/rustc-perf.

@rustbot label: -perf-regression

Footnotes

1. the arithmetic mean of the percent change↩↩²

2. number of relevant changes↩↩²