Donnie is correct, disc brakes need a larger reservoir due to the volume of fluid needed. Internals (residual check valves are different between disc/drum ) are different, so theoretically a disc brake M/C with larger reservoirs can also work on drum brake set-up, but not a drum brake M/C on a disc set-up (because of the smaller reservoir).
Actually its done all the time. As long as the piston stroke and diameter are close, all they do is leave the residual valve out of the primary port. Not ideal, but safe enough the big companies have been selling that way for years.