The sidplay libraries are stupidly split up into not two, but three separate libraries! Or so it seems. There is libsidplay, libsidutils, and libresidbuilder. When I try to compile mpd with sidplay support, it complains about either libsidutils or libresidbuilder missing.
So I google for libsidresidbuilder, and I get a packages.debian.org page for the package. I download and unpack it and hmm, it looks exactly like the libsidplay package from portage! There are libsidplay, libsidutils, resid, and builder subdirectories.
My guess is that libsidplay in portage is just not compiling the resid and libresidutils? Maybe some USE flags need to be suggested to allow building these, although I can’t imagine why you wouldn’t want to build them.
Tags: libsidplay, mpd, sid