It's more useful to track changes by including a 
changelog file than adding a single string to the 
command line. 
 
A changelog file should be formatted to included 
without change into an rpm specfile -- and may 
contain one or more entries, constituting the history 
of the package.  This gets dumped into the %changelog 
section of the intermediate spec-file. 
 
For example; a file called ChangeLog could have the 
following contents, which would then be propogated to 
the actual rpm by adding --changelog=ChangeLog to the 
command line. 
 
* Wed 17 Sep 2003 Tony Campbell 
<tcampbell@users.sourceforge.net> 
- ported to ppc 
- another message 
 
* Tue Aug 19 2003 Tony Campbell 
<tcampbell@users.sourceforge.net> 
- Created