first part of Benoît Vaugon's format-gadts patch
    
    After applying this patch, you should run:
    
      make library-cross
      make promote-cross
      make partialclean
      make ocamlc ocamllex ocamltools
    
    and then immediately apply the following patches until the "second
    part of Benoît Vaugon's format+gadts patch"; the bootstrap cycle is
    not finished yet.
    
    git-svn-id: http://caml.inria.fr/svn/ocaml/trunk@14806 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02