Don't cast second argument of mem_printf_hook (%b) to size_t.

Don't cast second argument of mem_printf_hook (%b) to size_t.

Also treat the given number as unsigned int.

Due to the printf hook registration the second argument of
mem_printf_hook (if called via printf etc.) is always of type int*.
Casting this to a size_t pointer and then dereferencing that as int does
not work on big endian machines if int is smaller than size_t (e.g. on ppc64).

In order to make this change work if the argument is of a type larger
than int, size_t for instance, the second argument for %b has to be casted
to (u_)int.