[CentOS] rpmbuild question

Hi, folks,

   Trying to build a package from a gzipped tarball of a python package.
I'm trying to build it in /root/rpmbuild. Python has a way to build it,
but it creates its own tree, with a clone of the rpmbuild tree under
*that*.

   So, from the specfile, I'm trying to understand, after much googling,
what I need to change the Source and BuildRoot to. My latest try for
the latter is
BuildRoot: %{_builddir}/BUILD/%{name}-%{version}-%{release}
For Source0, I want to use the file in SOURCES.

   Anyone got a better example than what I've been googling?

       mark