Coqmktop: dynlink is now mandatory due to Maxime's native-compiler

 Some cleanup btw, for instance Dynlink.init is deprecated since at least
 ocaml 3.11

git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@16419 85f007b7-540e-0410-9357-904b9bb8a0f7