GCC undefined behaviors are getting wild

I really like the idea of decompiling ones' own code with Ghidra to see different ways the logic can be represented. Using `-Wextra` adds a warning about the signed\unsigned comparison, but Ghidra's `(ulong)(uint)` casts make that a bit clearer.

This is a great writeup on what's possible with undefined behavior https://devblogs.microsoft.com/oldnewthing/20140627-00/?p=63...

If you want signed integer overflow to be defined, use the "-fwrapv" flag.