With this option enabled some lwip input processing occurs in the pp task which
works well for some uses but some code uses a lot of stack (e.g. mdns) and will
overflow the pp task stask, or might unnecessarily slow the critical pp task,
so disable this by default and if not already defined.
Also reduces the IRAM footprint of the fatal exception handler, as only
the prelude (which disables interrupts & enables the flash mapping) is
in IRAM now.
Closes#54, relevant to #133.
* This fixes the problem of axTLS symbols hmac_md5/hmac_sha1 having same
name as symbols in libwpa (which have incompatible signatures)
* Also allows for easier identification and piece-by-piece removal of
binary functions.
* Some libc symbols are not renamed, list is in lib/symbols_norename.txt
