Made Ethernet useable on 'Esp32 Dev Module'.

[reitowo]

Espressif's BSP changes the Client class and Server class's definition. When compiling on 'Esp32 Dev Module, we will receive messages indicating there are some pure virtual functions which are not implemented.
Adding these override functions will solve the following issues:

#97
#106
espressif/arduino-esp32#2786

[per1234]

Similar (but not exactly the same) to #95
As I commented there:

It seems like it would be better for the ESP32 core developers to follow the standard Arduino core API, rather than forcing every library to be patched to deal with the breakage they caused.

Related: #88

[per1234]

The need to have special declarations of EthernetClient::connect() for ESP32 was removed by espressif/arduino-esp32#3191.

Unfortunately, the situation with EthernetServer::begin() remains.

(Sorry for repeat comment. I realized this is more appropriate as a review than a comment.)

[berguinsson]

Hi guys!
Only one quick question. What does "BSP" mean?
The user called cnSchwarzer said Espressif's BSP changes...
I hope you can help me.
Thank you!

[per1234]

@berguinsson BSP is an acronym for "board support package". This is the term occasionally used to refer to the collection of software required to add support for specific boards to the Arduino development software. In this case, it's:
https://github.com/espressif/arduino-esp32
and more specifically, its core:
https://github.com/espressif/arduino-esp32/tree/master/cores/esp32
The officially recommended term is "platform", not "BSP".

[nmaas87]

Is there any updates on this? It is still failing builds on ESP32 :(
Thank you for your support :)!

[reitowo]

Reasonable, it is esp's fault, not this library.

[nmaas87]

Thank you for the information.
While I can understand Espressif should fix the interface, it will probably hurt the overall experience and for the users look like the Arduino library is faulty.

For those who come after me, because they badly need to use the sheer amount of libraries that build upon the Arduino Ethernet (especially MQTT, Webserver and Websocket) and now stand before a failing build: You'll need to frankenstein the src/Ethernet.h as shown in the pull request and it will make your other libaries work again