Allow overriding of build requirements at the class level.  Still do a build req check even is overrides are set to ensure we at least see everything that's requested.
Allow overriding of build requirements at the class level.  Still do a build
req check even is overrides are set to ensure we at least see everything
that's requested.

sassoftware/conary,sassoftware/conary,sassoftware/conary,sassoftware/conary,sassoftware/conary