simple question on Ping.cc compilation

[Gang Zhang <8gz@qlink.queensu.ca>]

Hi, NS expert:

I am trying to do the Ping protocol from Marc Greis' tutorial. 
But when I fetch the ping.cc and ping.h to ns directory, try to 
compile it using "gcc -c ping.cc", it give me the following error:

In file included from object.h:40,
                 from connector.h:40,
                 from agent.h:40,
                 from ping.h:12,
                 from ping.cc:9:
scheduler.h:40: tclcl.h: No such file or directory
In file included from packet.h:47,
                 from agent.h:41,
                 from ping.h:12,
                 from ping.cc:9:
packet-stamp.h:20: antenna.h: No such file or directory
In file included from agent.h:43,
                 from ping.h:12,
                 from ping.cc:9:
ns-process.h:36: tclcl.h: No such file or directory
In file included from agent.h:44,
                 from ping.h:12,
                 from ping.cc:9:
app.h:41: tclcl.h: No such file or directory
In file included from ping.cc:9:
ping.h:13: tclcl.h: No such file or directory
In file included from ping.h:15,
                 from ping.cc:9:
address.h:38: tclcl.h: No such file or directory
ping.cc:114: unbalanced `#endif'

could someone give me a hint? I know that tclcl.h is not in the ns
directory, but antenna.h do exist in that dir(ns-2.1b5). it is confusing.

Actually, when I try to compile some old file(like red.cc) -- just want to
test compilation, it has the same problem.

Thanks for your help.

Grant