Allow cdylib targets

[vgwidt]

Adds a check to see if artifact is a cdylib target to fix regression in #476. Fixes #575

Checklist

• Updated CHANGELOG.md describing pertinent changes.
• Updated README.md with pertinent info (may not always apply).
• Updated site content with pertinent info (may not always apply).
• Squash down commits to one or two logical commits which clearly describe the work you've done. If you don't, then Dodd will 🤓.

[ctron]

I cherry-picked this into trunk-ng.

[arne-fuchs]

So only your fork supports cdylib? @vgwidt

[vgwidt]

ctron has it included in his fork as well, and he looks to be cutting releases in case you want other recent fixes: https://github.com/ctron/trunk

[ctron]

This was brought back to trunk with PR #623 and it should be part of the next release of trunk too.

[ctron]

This was released with trunk 0.18.0