Where is `memcmp` in std lib? Or `cmp()` for byte sequences?

[cblake]

Well, `equalMem` uses `system/memory.nimCmpMem` and this works: 
    
    
    import system/memory
    var a = "hi"
    var b = "ho"
    echo nimCmpMem(a[0].addr, b[0].addr, 2)
    
    
    Run

No idea if it should "always work going forward", but it's been around since 
early 2019.