All entries in token_info array should be c_ulong, based on definition
of CK_TOKEN_INFO in opencryptoki's pkcs11types.h.

Otherwise we get an overflow:

error: literal out of range for `isize`
  --> src/pkcs11/object_class.rs:18:21
   |
18 |     VendorDefined = 0x80000000,
   |                     ^^^^^^^^^^
   |
   = note: `#[deny(overflowing_literals)]` on by default
   = note: the literal `0x80000000` (decimal `2147483648`) does not fit into the type `isize` and will become `-2147483648isize`

Instead use macros to check size of pointers, and thereby determine if
we are on 32bit or 64bit platform.  On 32bit platforms c_ulong is u32,
and otherwise u64.

This works well for android, but I suppose there might be other exotic
platforms where size of c_ulong and size of pointers do not
necessarily follow each other.