The project's name is libbsc and not libsc, libsc PKGBUILD hasn't been updated in a while, while libbsc PKGBUILD provides the latest version. Both were submitted by the same person and judging from the submission time I think libsc was just a typo. https://aur.archlinux.org/packages/libbsc/ https://aur.archlinux.org/packages/libsc/