incude_lib question

[bokner]

Why include_lib works with application names for some applications and
doesn't for others? For example, I have exmpp application installed in
my Erlang lib directory, and include_lib doesn't see headers when I
do:

include_lib("exmpp/include/some_header.hrl"),

while it works for crypto, mnesia, kernel apps etc.?

There must be some packaging option that affects this, but I couldn't
find it. Thank you for help.