[erlang-questions] Emacs + Flycheck + rebar3 + proper

[Frans Schneider]

Hi all,

In emacs while editing PropEr tests, flycheck complains about not being 
able to find "proper/include/proper.hrl" which is obvious since that lib 
is somewhere sitting in the _build directory and not defined in ERL_LIBS.
How do you guys configure emacs in a situation like this?
PropEr is part of the test profile in rebar3.

Thanks.

Frans