Have you considered to extend bsd.lib.mk suffix rules? The fact is that it already build multiple ABIs / signatures (.o / .po / .go / .so). I think that direction is more straightforward.
I'm considering to extend that for crunch binaries. Crunch object is another ABI, and *.cro (the one just before linked) is kind of a static library. Masao -- Masao Uebayashi / Tombi Inc. / Tel: +81-90-9141-4635