fix: patch msc_find_lib.m4 for multiarch library detection

[fzipi]

ModSecurity v3.0.15 refactored library detection to centralize hardcoded architecture paths in build/msc_find_lib.m4. The ssdeep.m4 and pcre2.m4 files are now thin wrappers that delegate to MSC_CHECK_LIB.

Patch only msc_find_lib.m4 to replace 'i386-linux-gnu' with the actual detected architecture. This fixes SSDEEP library detection on arm64 and other non-x86 platforms.

Fixes build failures on linux/arm64 and linux/i386 with ModSecurity v3.0.15.

Summary by CodeRabbit

• Chores
  • Updated ModSecurity build configuration in Docker images (standard and Alpine variants) to refine multi-architecture support during the build process.

[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: e8b8c904-b94e-45ff-835e-6f3cffcac5fd

📥 Commits

Reviewing files that changed from the base of the PR and between dbcb017 and 5fd0a41.

📒 Files selected for processing (2)

• nginx/Dockerfile
• nginx/Dockerfile-alpine

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📝 Walkthrough

Walkthrough

This pull request updates the ModSecurity build-time architecture substitution logic in both nginx/Dockerfile and nginx/Dockerfile-alpine. The sed command that previously patched ssdeep.m4 and pcre2.m4 is changed to patch msc_find_lib.m4 instead, altering which build configuration script receives the architecture variable substitution.

Changes

ModSecurity Build Architecture Substitution

Layer / File(s)	Summary
Architecture substitution target redirection nginx/Dockerfile, nginx/Dockerfile-alpine	The build-time sed command that performs the i386-linux-gnu → ${ARCH} substitution is retargeted from build/ssdeep.m4 and build/pcre2.m4 to build/msc_find_lib.m4 in both Dockerfile variants.

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~3 minutes

Poem

A rabbit hops through Dockerfiles with glee,
Substituting paths where libraries be,
From ssdeep and pcre2's old nest,
To msc_find_lib—now that's the best! 🐰✨

🚥 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 accurately summarizes the main change: patching msc_find_lib.m4 to fix multiarch library detection in ModSecurity, which is the core objective of the PR.
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.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/modsec3-arch-detection

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[Copilot]

Pull request overview

This PR updates the ModSecurity v3 build patching logic for nginx images to match ModSecurity 3.0.15’s refactored library detection, where architecture-specific paths are centralized in build/msc_find_lib.m4.

Changes:

• Replaces separate patches to ssdeep.m4 and pcre2.m4.
• Applies the architecture replacement once in msc_find_lib.m4.
• Keeps both Debian-based and Alpine nginx builds aligned.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
nginx/Dockerfile	Updates Debian-based nginx ModSecurity v3 build patching to target msc_find_lib.m4.
nginx/Dockerfile-alpine	Updates Alpine nginx ModSecurity v3 build patching to target msc_find_lib.m4.

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