LWIP errno handling

[podaen]

I'm starting with an old ESP32 and I refuse to step over to an newer device until those problems are solved.

After investigating the network #6664 , I have seen that pings fluctuations can influence the behavior of receiving data, even transmitting data.

After investigation of the WiFi network data doesn't come in properly. Out of my testing the data of the WiFiClient is not able to collect all data with the current LWIP. Read is required!

To do, Errno handling is needed to collected WiFiClient data. The current flags MSG_DONTWAIT is not able to handle EAGAIN properly with read. Errno 11 is only confirming to MSG_OOB, MSG_PEEK, and MSG_WAITALL. MSG_OBB and those doesn't support older protocols without header that are convenient with newer data streams

To enable the read in the LWIP, #if LWIP_POSIX_SOCKETS_IO_NAMES needs to be #defined in lwipopts and this causes a conflict with previous declaration int fcntl(int, int, ...).

Can this addaped... added to the read the ESP socket or maybe declared in a higher hierarchic?

[podaen]

There is nothing wrong with the current settings, they just need a little attention.