comm: Properly handle I/O errors when reading input

[dezgeg]

No description provided.

[github-actions]

GNU testsuite comparison:

Skipping an intermittent issue tests/shuf/shuf-reservoir (passes in this run but fails in the 'main' branch)
Skipping an intermittent issue tests/sort/sort-stale-thread-mem (passes in this run but fails in the 'main' branch)
Skipping an intermittent issue tests/tail/inotify-dir-recreate (passes in this run but fails in the 'main' branch)
Congrats! The gnu test tests/basenc/bounded-memory is now passing!

[codspeed-hq]

Merging this PR will improve performance by 3.25%

⚡ 1 improved benchmark
✅ 141 untouched benchmarks
⏩ 180 skipped benchmarks¹

Performance Changes

	Mode	Benchmark	BASE	HEAD	Efficiency
⚡	Simulation	du_max_depth_balanced_tree[(6, 4, 10)]	33.1 ms	32.1 ms	+3.25%

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_{Comparing dezgeg:comm_ioerr (a2715e1) with main (fca717a)}

Footnotes

1. 180 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. ↩

[cakebaker]

Thanks!