Everything I have found is documented in their respective github repositories.

This is my main issue https://github.com/band115/ecirca/issues/38

I can't find much docs on how to use rebar's {pre_hooks, [{compile, ...

$ERL_CFLAGS is set to (note the extra quotes).

-I"/usr/local/Cellar/erlang/17.3.4/lib/erlang/lib/erl_interface-3.7.19/include" -I"/usr/local/Cellar/erlang/17.3.4/lib/erlang/erts-6.2.1/include"

I don't know if this issue befalls on the erlang distribution (homebrew) on my system, rebar or ecirca ..