Add several constants needed to use multicast UDP

[jepler]

This was verified by @todbot to work on esp32 s2 and s3; the constant should match any system that uses LWIP numbering.

It enables use of multicast UDP and gets rid of the need for this block in https://github.com/todbot/CircuitPython_MicroOSC/blob/main/microosc.py#L55:

if impl == "circuitpython":
    # these defines are not yet in CirPy socket, known to work for ESP32 native WiFI
    IPPROTO_IP = 0  # super secret from @jepler
    IP_MULTICAST_TTL = 5  # super secret from @jepler
else:
    import socket
    IPPROTO_IP = socket.IPPROTO_IP
    IP_MULTICAST_TTL = socket.IP_MULTICAST_TTL

[dhalbert]

Maybe add this to 8.2.x?

[jepler]

re-worked to apply to 8.2.x.

[todbot]

awww thanks

[gamblor21]

Checked the values are correct and was able to build/test (UM FeatherS2):

import socketpool
socketpool.SocketPool.IPPROTO_IP
0
socketpool.SocketPool.IP_MULTICAST_TTL
5