PDBs reveal that these functions are also used in winspool.drv, but not imported from spoolss.dll to retain the client/server architecture.
As winspool.drv highly benefits from the MarshallUp* functions, I put them in a source file shared between spoolss.dll and winspool.drv.
The added API Tests cover my testing and all implemented features.
One more item done from https://reactos.org/wiki/Printing !
