Does anyone know of a method that can be used to determine, from software, whether an 11.0592MHz or 22.1184MHz crystal is connected to a processor?

Pretty stupid requirement, I know, but I really need to be able to do this.

I don't want to use an external RC circuit connected to a port pin and I just can't think of an elegant way to do this in software, I don't even know if its possible.

Any ideas?

Thanks.