Is there any way of casting the CDECL_ type to *int?
No, because CDECL_ is not a type. It’s a calling convention. Calling conventions specify how arguments are passed, who is responsible for restoring the stack, and so on. It has nothing to do with the type of data returned.
If you want to cast the results to an *int, you will need to look at the type of data the function is returning.