In other words, you should be able to compile and run any A/UX application
under System V.2, as long as the A/UX application does NOT either interact
with hardware or make library calls to the Apple enhancements to System V
-- such as Toolbox, rpc services, BNet (sockets), etc.
The reverse is also true: because A/UX has passed SVVS (System V Validation
Suite), any System V program that follows the SVID (System V Interface
Definition) will run under A/UX.