install: retry strip program spawn on ETXTBSY

[krosci]

On Linux, exec(2) of a script (e.g. the #!/bin/sh strip wrapper) transiently fails with ETXTBSY when another process is concurrently exec'ing the same interpreter, because the kernel denies write access to the file for the duration of the exec; CI's parallel test load turns this into an intermittent failure. BSD kernels already sleep and retry on ETXTBSY (see exec(3)), and install now does the same, retrying the strip-program spawn up to three times with a short delay, so genuine errors (missing program, permission, non-zero exit) still fail immediately. Unit tests cover the retry path and confirm only ETXTBSY triggers a retry.

Closes #14520

[github-actions]

GNU testsuite comparison:

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

[krosci]

@xtqqczze could you take a look at it? Thanks!

[xtqqczze]

could you take a look at it? Thanks!

With #14586, it would be possible to remove all the cfg(unix) annotations. I’ll wait for a decision on that PR before proceeding.

[xtqqczze]

Please rebase to remove the unrelated whitespace changes.

[krosci]

It's already at the last commit.

[xtqqczze]

Sorry, this is a bad merge.

[xtqqczze]

You will need to cherry-pick from the commit before @sylvestre pushed a merge commit into your branch:

git fetch upstream
git checkout fix/install-strip-text-file-busy
git reset --hard upstream/main
git cherry-pick db64ed6cbe422cc36f2035625fe7774f27094dbd

[krosci]

I believe I'm done

[codspeed]

Merging this PR will degrade performance by 15.86%

❌ 1 regressed benchmark
✅ 75 untouched benchmarks
⏩ 355 skipped benchmarks¹

Warning

Please fix the performance issues or acknowledge them on CodSpeed.

Performance Changes

	Benchmark	BASE	HEAD	Efficiency
❌	false_consecutive_calls	294.7 ns	350.2 ns	-15.86%

Tip

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

---

_{Comparing krosci:fix/install-strip-text-file-busy (ddb44cc) with main (93e535b)²}

Footnotes

1. 355 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. ↩

2. No successful run was found on main (47df573) during the generation of this report, so 93e535b was used instead as the comparison base. There might be some changes unrelated to this pull request in this report. ↩