The C library code here mostly comes from The Public Domain C Library (pdclib).

Get it here:         https://rootdirectory.de/doku.php?id=pdclib:start
and here's the repo: https://github.com/DevSolar/pdclib


The original code is licensed under CC0 (Public Domain), and I'm really having a hard time
keeping track which file has been modified and how, etc.