The source code for Daizu is itself stored in a Subversion repository. Anonymous read-only access is available for anyone who wants to take a look at the current version of the sources. Be warned that this wont always be in a functioning state.
To get a working copy, run a checkout command like this:
svn co svn://svn.daizucms.org/cms/Daizu/trunk Daizu
Of course you wont be able to commit from that working copy unless I've given you a username and password.
If you want to use the Build.PL script you'll have to create it first by running ./mkbuild.pl.