@User: I have added the mapping above suggested by @User as well as those for the other standard cell libraries to open_pdks (https://github.com/RTimothyEdwards/open_pdks/pull/29) and openlane (https://github.com/efabless/openlane/tree/develop-dlatch_support). Btw, there's an open issue about that same thing at the yosys repo (https://github.com/YosysHQ/yosys/issues/1221).