Building seyon. Where xmkmf?

[plug-discuss@lists.plug.phoenix.az.us]

OK, I want to try the X windows based serial 
port terminal program seyon.  I downloaded the 
source.  The docs say to "run xmkmf" to begin 
the build process.

I don't have this xmkmf on my Red Hat 7.2 or 7.3 
system.  I find references to it all over the 
net but no place where I can download it.

A) Does anyone know where I can download this 
makefile generator utility?

OR

B) Can I build seyon without this utility, 
somehow using the Imakefile to generate a real 
makefile?

Or are there other options to get seyon?

Alan