$ qlist libclc | grep pkgconfig /usr/lib/pkgconfig/libclc.pc while that's not a valid pkg-config directory. If it's arch-agnostic, it should be /usr/share/pkgconfig. If it's not, it should be /usr/$(get_libdir) (lib64 here). Happens both with 0.0.1_pre20130524 and 9999.
This has been fixed upstream.