int types
=========

Which numeric types should/shouldn't SLUL have?

Definitely YES:
    byte
    intN/uintN/wintN (for N in {8,16,32,64})
        - but should these be broken down into e.g. uint:32 or something similar?

Yes:
    int   (= min(machine-word-size, 32), to avoid larger memory usage for arrays/structs on 64 bit platforms)
    usize

Maybe:
    ssize
    fileoffs

Maybe but unlikely:
    intN/uintN/wintN  for arbitrary N up to some limit

Optimized types (disallow in interfaces?)
Maybe but unlikely:
    {int,uint,wint}_leastN
    {int,uint,wint}_fastN  (= SIMD compatible?)
    reg_int (but some cpu arch's have different reg sizes, e.g. accumulator vs. X/Y regs. Or general purpose vs. SIMD regs)