So far the base address of the Ethernet chip was a general property of all Ethernet drivers. It served two purposes:
1. Allowing to use a single Ethernet driver for a certain Ethernet chip, no matter what machine was connected to the chip.
2. Allowing use an Ethernet card in all Apple II slots.
However, we now use customized Ethernet drivers for the individual machines so 1.) isn't relevant anymore. In fact one wants to omit the overhead of a runtime-adjustable base address where it isn't needed.
So only the Apple II slots are left. But this should rather be a driver-internal approach then. We should just hand the driver the slot number the user wants to use and have the driver do its thing.
Independently from the aspect if the driver parameter is a base address or a slot number the parameter handling was changed too. For asm programs there was so far a specific init function to be called prior to the main init function if it was desired to chnage the parameter default. This was done to keep the main init function backward compatible. But now that the parameter (now the slot number) is only used on the Apple II anyhow it seems reasonable to drop the specific init function again and just provide the parameter to the main init function. All C64-only user code can stay as-is. Only Apple II user code needs to by adjusted. Please note that this change only affects asm programs, C programs always used a single init function with the Apple II slot number as parameter.
Now that we have per-target combo driver wrappers we can remove the W5100 support from the C64. There isn't any actual (known) W5100-based solution for the C64.
Up to now every IP65 library contained exactly one Ethernet driver. In scenarios without strict memory limitations I might however be benefitial to have an IP65 library containing all Ethernet drivers available for a given target.
The Ethernet hardware detection that was already present before is used in this scenario to try to initialize one Ethernet driver after the other until one succeeds. If all drivers fail to initialize the user gets informed as usual.
The WIZ811MJ driver was primarily introduced for orthogonality reasons. There are however at least two W5100-based prototypes for the C64 so it makes at least some sense. The name was chosen as sort of placeholder for "something containing a W5100 chip".
