Fixing ocamldebug compilation by adding thread linking.

git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@16801 85f007b7-540e-0410-9357-904b9bb8a0f7
Adding evar printing to debugger.

git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@16802 85f007b7-540e-0410-9357-904b9bb8a0f7