fix(esp8266): If MEMLEAK_DEBUG is defined, create an alternate function
called `.._trace` that for each of `pvPortMalloc`, `pvPortZalloc`,
`pvPortCalloc` and `vPortFree`. The original function delegates to this new
tracing function but uses NULL and 0 for the file and line number. This ensures
that the pvPortMalloc exists as a symbol that can be used by the binary blobs
without any problems.
Example output from earlier usage:
~~~
--------Show Malloc--------
F:ppT L:512 malloc 2064 @ 0x3ffefd08
F:pmT L:256 malloc 1040 @ 0x3fff0518
F:tiT L:512 malloc 2064 @ 0x3fff0928
F:uiT L:640 malloc 2576 @ 0x3fff1138
F:IDLE L:176 malloc 720 @ 0x3fff1b48
F:Tmr Svc L:512 malloc 2064 @ 0x3fff1e18
~~~
fix(lwip): Remove declarations of `pvPortMalloc()` and family.
This fixes some of the issues in espressif/ESP8266_RTOS_SDK#189 but some of the
example applications fails. Not ready for merge but comments on my approach
will be appreciated.
