cuneicode
last updated: Oct 20, 2023
https://ztdcuneicode.readthedocs.io/en/latest/
https://github.com/soasis/cuneicode
The premiere library for handling text in different encoding forms for C software.
Apparently this person tried to get this to be the unicode interface in the C standard but was unsuccessful
Found via this extremely thorough critique of C unicode handling. news.yc comments