autotools: don't require multilib support on 32-bit systems

On 32-bit systems it doesn't make sense to require multilib
support. We can't run the 64-bit compiled code anyway.
libmemhack: fix max_obj calculation

With more than one memory class configured, the maximum number of
objects per class is calculated too high and the trainer will exit.

So also divide by the number of memory classes to correct this.
examples: add warzone2100 32-bit adaption