compat: Ensure alignment of reading dword width

[cosmo0920]

Sometimes, static inline uint32_t FLB_ALIGNED_DWORD_READ(unsigned char *source) function causes SEGV.
This is because just reading the bare pointer of unsigned char *source does not ensure the alignment.

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Fluent Bit is licensed under Apache 2.0, by submitting this pull request I understand that this code will be released under the terms of that license.

Summary by CodeRabbit

• Bug Fixes
  • Improved compatibility when reading unaligned data on platforms without strict alignment enforcement.
  • Prevented potential memory access issues by using safer byte-copy operations.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: f9744ca7-4def-42f0-b858-e4e3c82f3fe2

📥 Commits

Reviewing files that changed from the base of the PR and between ae51533 and 3882ca0.

📒 Files selected for processing (1)

• include/fluent-bit/flb_compat.h

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📝 Walkthrough

Walkthrough

The compatibility header adds the required string library include and updates non-aligned DWORD reads to copy four bytes into a uint32_t with memcpy.

Changes

Aligned DWORD reads

Layer / File(s)	Summary
Memcpy-based DWORD read include/fluent-bit/flb_compat.h	Adds <string.h> and replaces the potentially unaligned pointer dereference with memcpy into a local uint32_t result.

Estimated code review effort: 2 (Simple) | ~10 minutes

Mergeability Score: ⚪ Minimal · up to 3882c

This is a localized compatibility change, and no actionable merge-blocking risk remains after normal checks and review.

Suggested reviewers: edsiper, leonardo-albertovich

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly summarizes the main change: ensuring aligned 32-bit reads in the compatibility code.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

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🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch cosmo0920-plug-segv-on-sb

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[chatgpt-codex-connector]

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