RPM question: how to split an existing package in two?

[Tom Lane]

Per a customer suggestion, I recently separated mysql's client libraries
out of the base "mysql" RPM into a new "mysql-libs" RPM.  I thought this
would be a trivial change, but it seems "yum upgrade" fails to cope:
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=234712

Would someone slip me a clue on what I did wrong?  I suppose I'm lacking
some specfile directive, but I dunno what...

			regards, tom lane