yac is built using preconfigured configure script and further flags added to yac and yaxt to bring it close to icon

lib64 folder added to fyaml-libs only if it exists (thank you levante); minor change to run on macos

cleaned up the partial building of deps via yac and made it entirely a user responsibility to manage the yaco deps enforced via the icon-stack

changed the way of handling yaco version in the yaco-build script to avoid extra step in the release