fix: activate --as-needed shared libraries for weak symbol references

[PritamP20]

When --as-needed is active, Wild was dropping shared libraries from DT_NEEDED if the only reference to one of their symbols was weak. This diverges from GNU ld and lld, which both include the library in this case.

The fix is in resolve_symbol in libwild/src/resolution.rs. Previously, try_request_file_id (which marks a library as needed) was only called for strong references. The condition now also activates shared libraries for weak references, while preserving the existing behaviour for archives weak references to archive members should still not force them to be pulled in.

Fixes #1665

Tests

Mold test as-needed-weak.sh now passes removed from misc skip group:

running 2 tests
test external_tests::mold_tests::verify_skipped_mold_tests_still_fail::mold_test_101__UP_external_test_suites_mold_test_as_needed_weak_sh ... ok
test external_tests::mold_tests::check_mold_tests_regression::mold_test_101__UP_external_test_suites_mold_test_as_needed_weak_sh ... ok

test result: ok. 2 passed; 0 failed; 0 ignored; 0 measured; 1045 filtered out; finished in 0.14s

[davidlattimore]

It might not be an archive. It could also be a regular object file right?

[PritamP20]

Yeah, it can be a regular object file too I'll fix the comment. The main thing this block handles is the case where a weak reference to a shared library wasn't activating it for --as-needed, so it was getting dropped from DT_NEEDED

[davidlattimore]

Do the tests pass for you locally? If they do, then you might want to look at your test-config.toml or copy test-config-ci.toml if you don't have one.