base32/base64/basenc: accept a -w value starting with - to match GNU

[AlejandroCoronadoN]

base64 -w -5 (and any -w value that starts with -, e.g. -w -d) was rejected by the argument parser with unexpected argument '-5' found, while GNU takes the token after -w as the wrap size and reports invalid wrap size:

$ printf abc | base64 -w -5
error: unexpected argument '-5' found
$ printf abc | gbase64 -w -5
gbase64: invalid wrap size: '-5'

Adding allow_hyphen_values(true) to the -w/--wrap argument lets the value reach the existing wrap-size parser, which already emits the GNU-matching message. Verified against GNU for -w -5, -w -d, -w -x (all invalid wrap size), with valid values (-w 5, -w0, --wrap=5) and decoding unchanged. The shared base_common.rs covers base32, base64 and basenc.

[codspeed-hq]

Merging this PR will improve performance by 3.7%

⚠️ Different runtime environments detected

Some benchmarks with significant performance changes were compared across different runtime environments,
which may affect the accuracy of the results.

Open the report in CodSpeed to investigate

⚡ 2 improved benchmarks
✅ 355 untouched benchmarks
⏩ 50 skipped benchmarks¹

Performance Changes

	Mode	Benchmark	BASE	HEAD	Efficiency
⚡	Simulation	cksum_crc32b	39.7 ms	38.1 ms	+4.19%
⚡	Simulation	cksum_sysv	68.4 ms	66.3 ms	+3.22%

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.

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_{Comparing AlejandroCoronadoN:base-wrap-hyphen-value (48e182d) with main (36947fc)}

Footnotes

1. 50 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/tail/pid-pipe (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)

[oech3]

Suggested change

// GNU takes the token after -w as the wrap size even when it starts with '-'.

Comment is unnecessary if you added test.