Patch eap.o memory leak

[mhightower83]

WiFi Enterprise option can leak up to 3 allocations per connect/disconnect cycle (configuration dependent): anonymous Identity, password, and some unidentified allocation.

This solution patches eap.o from libwpa2.a to call a special 2-part wrapper instead of vPortFree at cleanup.

This is supplemental to #8529 (comment) and should not be merged prior.

There may be a better way of doing this. My knowledge of xtensa-lx106-elf-objcopy is near zero and everything that sounded promising didn't work the way I needed.

I don't have a use case for WiFi Enterprise so my testing has been limited. More testing is needed.

To minimize resources used, the patch will only be linked in when you have a call to enable_wifi_enterprise_patch().

Use something like this to enable patch:

#include <ESP8266WiFi.h>
#include <coredecls.h>
// ...
void setup() {
  enable_wifi_enterprise_patch();
// ...
}

[Flole998]

Excellent job, I am really impressed. I tried to do something similar but failed miserably.

[earlephilhower]

I've been watching this for a while and just want to say, great work @mhightower83 ! You must have spent much time delving through disassembled code to fix this!

[mhightower83]

@earlephilhower Thanks! I started using this bug to test some code I was working on to catch a double free. I ended out making several more debug enhancements to umm_malloc. These helped reduce the amount of assembly code I was reading.