Prudently revert the type of "Cconst_symbol" to typ_val instead of typ_int.
There seems to be issues with let-bound variables initialized with symbol
addresses and later updated.


git-svn-id: http://caml.inria.fr/svn/ocaml/branches/cmm-mach-types@15572 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02