include/coap2/libcoap.h
_LIBCOAP_H_ to COAP_LIBCOAP_H_
src/coap_session.c
_COAP_SESSION_H_ to COAP_SESSION_C_
include/coap2/coap_session.h
_SESSION_H_ to COAP_SESSION_H_
otherwise, all #define _COAP_xxxxx wrappers are now COAP_xxxxx
Fixes#291
Automake is using the variable 'libcoap_include_HEADERS' as the list to
install the header files and is this list installing to $(prefix)
basically.
This commit is changing the primary installation folder for the header
files in addition to the previous commit.