Attached is a patch to lower the version requirements of libtool and

Attached is a patch to lower the version requirements of libtool and
automake.  I have tested this on CentOS 4.x with the specified
versions of libtool and automake and was able to build RRDTool fine.
I did *not* test building with PHP, tcl, ruby or Python though.

I also abstracted the version numbers of all the dependencies such
that editing them in the future will be easier.
-- Bernard Li

git-svn-id: svn://svn.oetiker.ch/rrdtool/trunk/program@1537 a5681a0c-68f1-0310-ab6d-d61299d08faa