with musicbrainz-2.1.1-r1 installed, tunepimp-0.3.0-r1 failed to configure looking for mb_GetVersion in -lmusicbrainz. After emergeing musicbrainz-2.1.2 the compile of tunepimp worked. Just a version bump on (R)DEPEND needed.
I don't know what caused it before but I can't reproduce it. Retested musicbrainz-2.1.2 with tunepimp-0.[34].0 and it worked fine.
Created attachment 90487 [details] emergelog proof that I wasn't insane when this popped up. Unfortunately I don't have config.log and can't reproduce. If anyone else is reading this saying this happened to me attach emerge info, the /var/tmp/portage/tunepimp-{version}/work/tunepimp-{version}/config.log and reopen this bug.