Fix build with OCaml 3.12.0
Fix build with OCaml 3.12.0

The quotation <:ctyp< $a$ $b$ >> doesn't work any more with OCaml
3.12.0+beta1; we manually expand it.

Bug-OCaml: http://caml.inria.fr/mantis/view.php?id=5080
Bug-Debian: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=586493
Signed-off-by: Stephane Glondu <bf5cf299ce6ad0978a1465386899de8d6e61819d@glondu.net>

bennn/batteries-included