From a crankcase source checkout, running "rake build_setup" generates a large yum install command, which appears to be based on requirements in manifest files.
some of these manifest files contain requirements like "php <= 5.3.2".  This results in warnings from yum like:

"No package 5.3.2 available"

Since the command uses "--skip-broken", it doesn't actually cause a fatal error, but it should be fixed nonetheless.