Ah, thank you! I replaced: "libs-windows-x86-dmd"
with: "sourceFiles-windows-x86-dmd" (and added a .lib suffix) and now everything works as expected.I see now that I was using "libs" improperly. It seems more for system-wide libraries / things in the library search path, not to be used for individual .lib files.
Thanks again, you saved me many hours this morning :)