Support for the Ruby 2.4 series has ended. See here for reference.
See also BigDecimal.new
static VALUE BigDecimal_global_new(int argc, VALUE *argv, VALUE self) { ENTER(1); Real *pv; VALUE obj; obj = TypedData_Wrap_Struct(rb_cBigDecimal, &BigDecimal_data_type, 0); GUARD_OBJ(pv, BigDecimal_new(argc, argv)); if (ToValue(pv)) pv = VpCopy(NULL, pv); RTYPEDDATA_DATA(obj) = pv; return pv->obj = obj; }