How to make rsyslog tcpflood?

I have setup a rsyslog-server and want to test it. I am following link how-to-use-tcpflood for it.

This link says, "This tool is included in the local rsyslog folder in ‘tests’". What does it mean by local rsyslog folder? I have rsyslog (v 8.24.0-0adiscon2xenial1) installed on ubuntu machine; but it does not have any folder named "tests".

Assuming that, it might be the source code from github for rsyslog, I cloned http://ift.tt/2kMEDla. The project does contain folder "tests". I run "make tcpflood" as instructed. But it fails.

~/rsyslog/tests$ make tcpflood
cc     tcpflood.c   -o tcpflood
tcpflood.c:86:20: fatal error: config.h: No such file or directory
compilation terminated.
<builtin>: recipe for target 'tcpflood' failed
make: *** [tcpflood] Error 1

What I am missing? How can I get tcpflood running?