After all the Ethernet cards/carts are different enough to ask for customized drivers. Building the drivers individually opens the option to use .ifdef's to customize them.
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".
* CS8900A
The Contiki driver allows to adjust the chip base addr at runtime (which allows to support different slots in the Apple II) and removes received frames from the chip if there's no room to send frames.
* LAN91C96
The Contiki driver was used by IP65 more or less unchanged in the first place.
* W5100
The Contiki driver allows to adjust the chip base addr at runtime (which allows to support different slots in the Apple II) and stays clear from the W5100 hybrid mode. It presumes a fully functional W5100 register auto-increment and pre-calculates necessary W5100 frame buffer wrap-arounds and thus achieves the maximal 6502 <-> W5100 transfer speed.
