Your library paths look correct to me.

Did you try skipping declaring the namespace and create a pps object?
#include <qpps/object.h>
QPps::Object *testObject = new QPps::Object(QStringLiteral("/pps/services/test"), QPps::Object::PublishAndSubscribeMode, false, this);

You should be able to just do LIBS += -lqpps since you are setting the INCLUDEPATH and DEPENDPATH to it's directory.