passing an option to rpmbuild

[Dave]

Hello,
	I'm trying to repackage an rpm, in this case pure-ftpd. I want to
add in mysql support, in the spec file there's a section without_mysql which
stops it from being compiled in. I'm trying to pass with_mysql on the
rpmbuild commandline:

rpmbuild with_mysql pure-ftpd.spec

	and other variations. I've checked out the rpmbuild man page and
googled and have not found this.
	Thanks.
Dave.