pkg-config output is inconsistent with example5.cpp

[yurivict]

$ c++ -o example5 example5.cpp `pkg-config --cflags --libs jrtplib`
example5.cpp:6:10: fatal error: 'rtpsession.h' file not found
#include "rtpsession.h"
         ^~~~~~~~~~~~~~

This is because rtpsession.h is installed into /usr/local/include/jrtplib3/rtpsession.h and pkg-config doesn't include this directory:

$ pkg-config --cflags --libs jrtplib
-I/usr/local/include -L/usr/local/lib -ljrtp