* dbusbind.c: Use XFASTINT rather than XUINT, and check for nonneg.

* dbusbind.c: Use XFASTINT rather than XUINT, and check for nonneg.

(Fdbus_call_method, Fdbus_call_method_asynchronously):
Use XFASTINT rather than XUINT when numbers are nonnegative.
(xd_append_arg, Fdbus_method_return_internal):
(Fdbus_method_error_internal): Likewise.  Also, for unsigned
arguments, check that Lisp number is nonnegative, rather than
silently wrapping negative numbers around.