[user01010111]

Following the load-reporting changes in #3739, consolidate the repeated library selection in tools/nut-scanner/nutscan-init.c into one private helper and explicit candidate lists. Preserve resolver-first lookup, fallback ordering, unload/reset behaviour, availability results and diagnostics, including libupsclient's different Windows ordering. Adapter loaders and public interfaces remain unchanged.

Compatibility and platform-specific rationale comments are retained beside the shared helper or candidate lists.

Add tests/nutscan-selection-test.c and register nine variants in tests/Makefile.am. The tests exercise real initialisation and the shared unloader with independent expectations for candidate order, entry and re-entry state, ownership and logging.

Validation:

• Linux GCC suite 25/25, including all nine selection variants and 8,064 total cases.
• Strict Clang: nine variants, 8,064 total cases, zero failures.
• Native Windows/MinGW: affected library code built with strict warnings; suite 24/24, including all nine variants and 9,540 total cases with configured warning flags retained and NDEBUG enabled.
• make distcheck-light and style checks passed; the archive contains the tested versions of the three code and build files.

Valgrind checks of the production library-selection and loading/cleanup paths reported no errors or lost blocks; retained allocations matched the baseline.

AI assistance: OpenAI Codex for implementation and tests; Claude Opus 5.5 for review.

[github-actions]

A ZIP file with standard source tarball and another tarball with pre-built docs for commit 63bbb15 is temporarily available: NUT-tarballs-PR-3760.zip.

[AppVeyorBot]

✅ Build nut 2.8.5.5880-master completed (commit 13c001b6b4 by @jimklimov)

• artifacts
• A 7-zip archive with built NUT for Windows debug binaries is temporarily available: NUT-for-Windows-x86_64-SNAPSHOT-2.8.5.5880-master.7z
• ccache: 402 of 419 compilations were cache hits (95.9%); cache size 750 of 750 MiB after cleanup