libunistring provides a library that implements Unicode strings (in
three flavours: UTF-8 strings, UTF-16 strings, UTF-32 strings),
together with functions for Unicode charactets (character names,
classifications, properties) and functions for string processing
(formatted output, width, word breaks, line breaks, normalization,
case folding, regular expressions).

Homepage:
https://www.gnu.org/software/libunistring/
