6321: installed rcs and tried to make an archive


git-svn-id: svn+ssh://svn.code.sf.net/p/gramps/code/trunk@21083 4ae1f11a-8b86-4847-b8af-ab372f36d1fd
6318: Mention in the README that RCS is an optional package


git-svn-id: svn+ssh://svn.code.sf.net/p/gramps/code/trunk@21085 4ae1f11a-8b86-4847-b8af-ab372f36d1fd