tomcat 6 build from source-code

Hi Tomcat Gurus,
   Appreciated if you can help me with the following :

I'm trying to build tomcat server from the source code.  After downloading
the source code, "ant " command was successful in executing the deploy
task. It created a folder "build" under "output" folder . The "build" folder
contains bin,conf,lib,temp,webapps directories.
 i)I was under the impression  that executing ant would build a jar-file or
file-structure similar to bin-download on tomcats website
ii)Even with the current structure,  I cannot see any startup/shutdown
scripts under this build folder.

Please let me know if I'm missing any step!

Thanks,
Chary