make tcpflood throws error

I am following this link ( http://ift.tt/2kt2que ) to send messages to rsyslog.

I have cloned the git repository of rsyslog http://ift.tt/2kMEDla

While following the link http://ift.tt/2kt2que , I am getting below error while executing "make tcpflood"

root1@atratus06:~/Debashish/rsyslog/tests$ make tcpflood

cc     tcpflood.c   -o tcpflood
tcpflood.c:86:20: fatal error: config.h: No such file or directory
 #include "config.h"
                ^
compilation terminated.
make: *** [tcpflood] Error 1

Can you please help me with the error, your help will be really appreciated.