Support alwayslink for linking with clang

[cerisier]

Simple approach to fix #1271

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[cerisier]

Thanks for having a look at this @scentini Just applied your suggestions.

[scentini]

Thank you for your contribution! CI says you also need to run ./docs/update_docs.sh before we can merge.

[archshift]

Any progress on this? It would be really great to see!

[cerisier]

@scentini up to date and docs generated.

[scentini]

Thanks @cerisier !