i18n: conditionally load SELinux/Smack locale strings based on feature flag

[ChrisDryden]

One of the issues with enabling the Smack support is that adding the locale for the SMACK errors adds a bunch of overhead even to the non-SELINUX or SMACK enabled utilities. The goal here is to reduce the overhead of adding new shared locale files by gating them behind the feature flag.

[oech3]

Cannot we do it at clap?

[codspeed-hq]

CodSpeed Performance Report

Merging this PR will degrade performance by 3.55%

_{Comparing ChrisDryden:selinux-locale-feature-gate (c358571) with main (20a5c3a)}

Summary

⚡ 18 improved benchmarks
❌ 1 regressed benchmark
✅ 121 untouched benchmarks
⏩ 37 skipped benchmarks¹

⚠️ Please fix the performance issues or acknowledge them on CodSpeed.

Performance Changes

	Benchmark	BASE	HEAD	Efficiency
⚡	wc_bytes_synthetic[500]	191.6 µs	176.9 µs	+8.34%
⚡	split_bytes	515.7 µs	498.9 µs	+3.38%
⚡	split_number_chunks	289.4 µs	279.9 µs	+3.38%
⚡	complex_relative_date	247.4 µs	235.6 µs	+5.03%
⚡	single_date_now	190.7 µs	177.9 µs	+7.18%
⚡	rm_single_file	123.8 ms	111.8 ms	+10.68%
❌	sort_long_line[160000]	1.7 ms	1.8 ms	-3.55%
⚡	tsort_input_parsing_heavy[5000]	73.7 ms	71.1 ms	+3.73%
⚡	cksum_blake3	219.2 µs	204.3 µs	+7.33%
⚡	b64_decode_synthetic	171 µs	157.2 µs	+8.79%
⚡	b64_decode_ignore_garbage_synthetic	169 µs	155.2 µs	+8.88%
⚡	b64_encode_synthetic	168.5 µs	153.6 µs	+9.73%
⚡	factor_multiple_u64s[2]	224.3 ms	195.8 ms	+14.56%
⚡	cp_large_file[16]	371.2 µs	355.4 µs	+4.44%
⚡	mv_force_overwrite	149.5 ms	128.5 ms	+16.34%
⚡	mv_single_file	140.9 ms	128.4 ms	+9.77%
⚡	dd_copy_8k_blocks	1 ms	1 ms	+3.22%
⚡	dd_copy_partial	572.1 µs	540.6 µs	+5.82%
⚡	dd_copy_64k_blocks	618.1 µs	589.4 µs	+4.85%

Footnotes

1. 37 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:

GNU test failed: tests/shuf/shuf-reservoir. tests/shuf/shuf-reservoir is passing on 'main'. Maybe you have to rebase?
GNU test failed: tests/sort/sort-stale-thread-mem. tests/sort/sort-stale-thread-mem is passing on 'main'. Maybe you have to rebase?
Skip an intermittent issue tests/timeout/timeout (fails in this run but passes in the 'main' branch)
Congrats! The gnu test tests/dd/nocache_eof is no longer failing!

[ChrisDryden]

@oech3 Can you elaborate on what you mean by that?

[oech3]

clap should recognize cfg-like config from *.ftl.

[ChrisDryden]

Now that the SMACK changes are in I can also do this for the SMACK locale translations, I'll update this PR

[github-actions]

GNU testsuite comparison:

Skipping an intermittent issue tests/tty/tty-eof (passes in this run but fails in the 'main' branch)

[ChrisDryden]

Now that we have an approach of not loading the translation files until they are needed, we don't really need to take this approach anymore