Fix Infinite Stack Recursion Regression.

Fix Infinite Stack Recursion Regression.

        * cp-tree.h (can_convert_arg, fn_type_unification): New argument.
        * call.c (add_template_candidate_real): Pass down 'flags' to
        fn_type_unification.
        (can_convert_arg): New 'flags' argument. Pass it to call to
        implicit_conversion instead of LOOKUP_NORMAL.
        (can_convert): Add LOOKUP_NORMAL to call to can_convert_arg.
        * class.c (resolve_address_of_overloaded_function): Ditto.
        (resolve_address_of_overloaded_function): Ditto.
        * decl.c (reshape_init, check_default_argument): Ditto.
        * typeck.c (build_ptrmemfunc): Ditto.
        * pt.c (type_unification_real): Add 'flags' argument.
        (fn_type_unification): Pass 'flags' to type_unification_real.
        (type_unification_real): Pass new 'flags' argument to call to
        can_convert_arg.

	Oked by Geoff Keating.

From-SVN: r103120