rpm包的制作

spec文件如下：
Summary: zlib-1.2.3 Installing RPM
Name:zlib
Version:1.2.3
Release: 1
License: Share
Group: Applications/Productivity
Source0: zlib-1.2.3.tar.tar
%description
zlib-1.2.3 Installing RPM
%prep
tar -xzvf $RPM_SOURCE_DIR/zlib-1.2.3.tar.tar
%build
cd $RPM_BUILD_DIR/zlib-1.2.3
./configure
make
%install
cd $RPM_BUILD_DIR/zlib-1.2.3
make install
%clean
rm -rf $RPM_BUILD_DIR/zlib-1.2.3
%files
%changelog
Fri Apr 18 2008 rebuild in the Redhat Enterprise 4

然后小弟用rpmbuild -ba XXX.spec
最后生成的rpm怎么才1.2k,根本不能用

请教高手，我哪里做错了？